The breadth of distribution of the erythrocyte population is reduced. What does RDW mean in a blood test. Increased red blood cell distribution width

The erythrocyte distribution width (RDW, from red cells distribution width) is an erythrocyte index that allows you to determine the heterogeneity of cell volume in peripheral blood.

The appearance in the blood of erythrocytes differing in volume is called anisocytosis, the degree of which makes it possible to determine the RDW index.

Red blood cells, their functions in the body, the main indicators

Erythrocytes, or red blood cells (RBC, red blood cells), are red blood cells, blood cells of a biconcave disc-shaped form, devoid of a nucleus. The shape of the erythrocyte allows the cell to deform as it moves through blood vessels small caliber. The main function of erythrocytes is the transport of oxygen from the lungs to tissues and organs, and from them - carbon dioxide to the lungs. RBCs are produced in the bone marrow and destroyed in the spleen average term cell life is 120 days. Newborns have larger red blood cells than adults.

A physiological increase in the number of erythrocytes is observed in children of the first days of life, with frequent stress, intense physical activity, malnutrition or starvation, with prolonged clamping of the limb with a tourniquet during blood sampling for a blood test. The physiological decrease in the number of red blood cells occurs immediately after eating, between 17:00 and 07:00 and in the case of taking blood from a patient in the supine position.

In the blood, in addition to normal red blood cells, there may be cells that differ in size - larger (macrocytes) or small (microcytes) red blood cells. A condition in which there are more than 50% of macrocytes in the blood is called macrocytosis. In the presence of 30–50% of microcytes, microcytosis is diagnosed. The appearance in the blood of erythrocytes differing in volume is called anisocytosis, the degree of which makes it possible to determine the RDW index.

The erythrocyte indices in the general blood test, in addition to RDW, include MCV (mean erythrocyte volume), MCH (mean hemoglobin content in erythrocyte), MCHC (mean hemoglobin concentration in erythrocyte mass).

Erythrocyte indices are determined during a general (clinical) blood test. Calculation is carried out using automatic hematological analysis torus, according to the appropriate formulas and / or in a stained blood smear under a microscope when calculating the leukocyte formula. The erythrocyte indices in the general blood test, in addition to RDW, include MCV (mean erythrocyte volume), MCH (mean hemoglobin content in erythrocyte), MCHC (mean hemoglobin concentration in erythrocyte mass).

How to prepare and take a general blood test

A general blood test is a basic study, which is carried out according to the following indications:

  • prevention, with the aim of early detection of probable pathologies;
  • diagnosis of diseases;
  • control of the therapy;
  • before surgical interventions;
  • monitoring the course of pregnancy.

A general blood test includes counting the number of blood cells (erythrocytes, leukocytes, platelets), determining the concentration of hemoglobin, hematocrit, erythrocyte and platelet indices, erythrocyte sedimentation rate. A detailed blood test includes counting the leukocyte formula.

For preventive purposes, a general blood test should be taken annually. Persons from risk groups (with aggravated heredity, the presence of chronic diseases, occupational hazards, during pregnancy, etc.) may need more frequent of this study - 2 times a year, 1 time in 3 months, and sometimes more often.

Blood for the deployed general analysis, which includes the determination of erythrocyte indices, including RDW usually taken from a vein. In some cases, capillary blood can be taken from a finger. Blood is taken in the morning on an empty stomach, at least eight hours after the last meal. Before donating blood, you should avoid mental and physical overload, stop smoking. It is advisable not to carry out medical procedures the day before.

If the RDW index is lowered, this often means the need to retake a complete blood count.

Deciphering RDW in a blood test: the norm in women and men

The RDW-CV indicator (CV - coefficient of variation) displays the relative width of the distribution of erythrocytes by volume, i.e. how much the volume of erythrocytes differs from the average, and is measured as a percentage. The index is influenced by the MCV indicator, fluctuations of which lead to an increase in RDW-CV. The norm of this indicator for adult men and women is 11-15%. In infants up to 6 months old, the RDW-CV rate is 15-19%. In children older than 6 months, the norm corresponds to that for adults.

When deciphering RDW-SD in a blood test (SD - standard deviation), it is taken into account that this indicator does not depend on the MCV index. This index shows how red blood cells are dissimilar in volume and size, that is, what is the difference between small and large cells. The norm of the RDW-SD indicator is 42 ± 5 fl.

The RDW-SD score is more accurate in the case of a small population of micro- or macrocytes, while the DW-CV index more accurately reflects the overall changes in erythrocyte volume.

Causes of abnormal RDW in a blood test

Elevated RDW means that there is heterogeneity, i.e., dissimilarity in the volume of the erythrocyte population, and may also indicate the presence of several populations of red blood cells in the blood (for example, after a blood transfusion).

If in the blood test RDW-CV is increased by 15% or more, this indicates the presence of red blood cells of different volume in the blood, the higher this index, the greater the difference in the volume of red blood cells. A falsely high RDW-CV result may be due to the presence of cold agglutinins in the patient's blood sample - antibodies that cause aggregation, i.e., aggregation of red blood cells in case of exposure to low temperatures.

Blood for a detailed general analysis, which includes the determination of erythrocyte indices, including the RDW index, is usually taken from a vein.

An increase in RDW is observed in the following pathologies:

  • microcytic anemia;
  • lack of iron, vitamin B 12 and / or folic acid in the body;
  • When deciphering the general blood test in general and the RDW indicator in particular, the values ​​​​of the erythrocyte index MCV are taken into account:

    • normal RDW + reduced MCV- after blood transfusion, post-traumatic splenectomy, chemotherapy, with hemorrhages, thalassemia, oncological diseases;
    • decreased MCV + increased RDW in a blood test- iron deficiency, fragmentation of red blood cells, beta thalassemia;
    • elevated MCV + normal RDW- with liver diseases;
    • increased MCV + increased RDW- with hemolytic anemia, vitamin B 12 deficiency, the presence of cold agglutinins in the blood sample, as well as during chemotherapy.
    Elevated RDW values ​​in a blood test can also be obtained immediately after surgery or a blood transfusion.

    If an RDW result is obtained that is outside the reference values, additional studies are needed.

    Video from YouTube on the topic of the article:

So what does such an erythrocyte index as RDW mean, what information does it carry to specialists and why is it used?

Distribution of erythrocytes by volume

If we examine under a microscope the red blood cells present in the blood of a patient suffering from a certain hematological pathology, we can find that the erythrocytes (Er) are not all the same in volume. Among all non-nuclear biconcave forms, there may be cells that differ significantly in size from normal erythrocytes:

  • Large cells - macrocytes;
  • Just giants - megalocytes;
  • Lilliputian cells, which are called microcytes.

And here it is not necessary to be a specialist in this field in order to understand that the red blood elements that have changed their volume will not be able to fully perform their physiological functions (transfer of oxygen and nutrients, regulation of water-salt metabolism and acid-base balance, participation in blood coagulation, etc.), which, of course, will affect the overall health of the body.

Meanwhile, one should not attach too much importance if ugly forms are present in single copies, it is another matter if they claim an equal position with normal erythrocytes. In order to find out how many in the general population of erythrocytes there are bizarre shapes characteristic of a particular type of anemia, and calculate the width of the distribution of erythrocytes (erythrocyte index RDW).

Many laboratory diagnostic physicians and hematologists take RDW as a coefficient of variation, indicating how much the average red blood cell volume (MCV) deviates from the generally accepted norm, and calculate it using the formula:

where SD denotes the standard deviation of the mean volume of red blood cells, and the MCV index corresponds to their mean volume.

Is it always possible to believe the norm?

The range of normal values ​​of the distribution of erythrocytes by volume varies within 11.5 - 14.5% (in children under six months, the norm, in general, differs markedly and ranges from 14% to 18.7%, although from 6 months the values ​​​​of the indicator are already begin to aspire to the norm of adults).

An elevated RDW in a blood test indicates the degree of heterogeneity (heterogeneity) of red blood cell populations or indicates the presence of several blood cell populations in the sample, which occurs, for example, after a recent blood transfusion.

It is hardly possible to use the term “reduced RDW value” when calculating the width of the distribution of erythrocytes, since this option reflects, as it were, the norm, and therefore cannot be taken as laboratory indicator characterizing some phenomenon unusual for these blood elements. The less unnatural forms (due to an increase or decrease in volume) of erythrocytes in the blood, the more representatives of the population for this trait are within the normal digital values. And yet, if this happens (RDW - lowered), then, most likely, the analyzer made a mistake, and in order to correct this oversight, the patient will have to provide a finger for a puncture again, and the laboratory staff will have to calibrate the device.

In addition, it should be taken into account that RDW, which is within the norm, is not always evidence full health, because in some cases, the distribution of erythrocytes by volume is not increased, and clinical manifestations and laboratory tests confirm the presence of the disease (anemia).

Increased RDW

An elevated index is quite a suitable indicator even for differential diagnosis some types of anemia, it allows you to distinguish between their forms:

  1. Megaloblastic and macrocytic, a typical representative is B12 / folic / -deficiency anemia. In the blood test: hyperchromia, the average volume of Er is above 160 fl, the cell diameter is more than 12 microns, RDW is increased (anisocytosis), different shape erythrocytes (poikilocytosis);
  2. Normocytic: aplastic anemia, as well as anemia caused by chronic pathology (tuberculosis, pyelonephritis, collagenoses, liver disease), a malignant process, or caused by dysfunction of the endocrine system;
  3. Microcytic ( Iron-deficiency anemia, in the blood test: hypochromia, anisocytosis towards microcytosis).

True, in such cases, in addition to RDW, the diagnosis also relies on another erythrocyte index - MCV, which characterizes a red blood cell as a normocyte (at 80 x / l - 100 x / l or 80 - 100 femtoliters), microcyte (at - below 80 fl), macrocyte (if the average volume is more than 100 fl).

In addition, when testing blood samples in order to calculate the values ​​of erythrocyte indices (including RDW), it is very important to compare the results obtained with the histogram of erythrocytes, which, after completing their work, is usually issued by modern hematological systems with software.

In this way, increased rate RDW with values ​​of the mean volume of erythrocytes (MCV) above 100 fl may indicate the following pathological conditions:

  • IDA (iron deficiency anemia) - the most common anemic condition (IDA accounts for up to 80% in the entire group of diseases of this kind)
  • Sideroblastic anemia (a heterogeneous group of hypochromic microcytic anemias);
  • Macrocytic and megaloblastic anemia;
  • Myelodysplastic syndromes, which are a hematological pathology that unites a group of heterogeneous diseases with characteristic signs of a decrease in the number of individual populations cellular elements blood (cytopenia) and clonal disorders of hematopoiesis in the bone marrow (dysplasia). Myelodysplastic syndrome is different high risk transformation into a malignant process;
  • Bone marrow metaplasia;
  • Metastases malignant tumors into the bone marrow.

Obviously, for a certain range of pathological conditions, the calculation of the width of the distribution of erythrocytes has a very important diagnostic value.

Why is RDW a new indicator for patients?

Before, while everyday life The laboratory service did not include automated hematological systems, the degree of anisocytosis was determined visually, when viewing a smear using optical equipment. And the distribution width of erythrocytes was not called RDW and was not calculated by a device designed for automatic hematological analysis. The calculation was carried out by a different method - using the Price-Jones curve, which, as it turned out later, did not coincide with the erythrocytometric curves performed by the “smart” machine with maximum accuracy, but it took a lot of effort and time for doctors and laboratory assistants to conduct the study. Now, having placed the sample in the "smart" apparatus, no one asks him one question - to work only on a separate test. The analyzer will simply calculate everything that is provided for by the program and is embedded in it, so patients began to see new indicators, which, when processing samples manually and was not in sight.

And such studies were previously of interest mainly to hematologists to clarify the nature of anemia, who, if necessary, applied to the laboratory with a note in the direction: morphological study erythrocytes, calculate and present graphically (Price-Jones erythrocytometric curve) the ratio of the number of red cells with different diameters. Of course, not all blood samples were subjected to such testing, but only samples taken from specific patients. Now, in principle, nothing has changed, this indicator is likely to be of interest to a separate circle of specialists. Well, if RDW is present in the blood test, then patients have the right to ask questions.

Currently, an automatic hematology analyzer successfully copes with the calculation of RDW in a blood test, which quietly, quickly and efficiently solves the problem. And makes RDW everyone.

Reasons for increasing and decreasing the width of the distribution of erythrocytes by volume

As you know, blood is formed not only by liquid (plasma), but also by various cellular elements, such as erythrocytes, leukocytes and platelets. All of them must have a certain size, volume (cv) and shape for normal functioning.

Any change in these parameters affects the usefulness and functional activity of cells, which can lead to various disorders of homeostasis. It was in order to be able to evaluate these cells that a special index was created - the distribution width of erythrocytes (RDW).

What does indicator mean?

This term is understood as an index that allows you to get an idea of ​​the distribution of cells of various sizes or shapes in the blood. Simply put, the width of the distribution of erythrocytes provides information about what percentage of erythrocytes in the blood, the size or volume of which is reduced or, conversely, more than necessary. Usually, it is used to evaluate the form, however, there is also its version for evaluation by volume - RDW-CV.

As you know, in order to supply oxygen to every cell of the body, an erythrocyte must pass even into the smallest vessels. That is why, physiologically, in size and size, the cells must correspond to the lumen of the vessels. If too large or vice versa, too small cells appear in the blood, this leads to the development various violations at the cellular and subcellular levels. As a result, it becomes necessary to determine the cellular composition of the blood using the RDW-CV indicator.

The distribution index of erythrocytes by volume in an adult is from 11 to 14.5%.

It is with this ratio of “atypical” cells that adequate blood supply to internal organs and tissues is still achieved. Reducing it below normal negatively affects the condition of the cells. In children, the norm of this indicator is slightly higher and can be up to 20%.

In addition to determining their volume, the calculation of the standard deviation (SD) is also shown. It quantifies the difference between the largest and smallest cell in an assay (usually referred to as RDW SD in assays).

Given all the variability and possible subsequent violations, it is necessary to understand in which cases an increase in RDW occurs, and when this index is lower than necessary.

Reasons for increasing the width of the distribution

The distribution width of erythrocytes is increased when the percentage ratio between small and large erythrocytes increases towards larger cells. Due to the redistribution of hemoglobin, which is the main molecule of the erythrocyte, a smaller amount of them is synthesized in the body, which leads to the development of anemia, as well as anisocytosis, a condition in which most of red blood cells is different from each other.

A characteristic feature of such cells, as mentioned above, are excessively large sizes, as well as a lifespan below the physiologically programmed. As a result, when they mass death(apoptosis in the spleen), a large amount of bilirubin is released, which negatively affects the condition of the liver and other internal organs.

The distribution of red blood cells by volume may be higher than normal as a result of:

  • lack of iron, folic acid and some B vitamins. It is a fairly common cause of anisocytosis, which leads to an increase in the width of the red blood cell distribution.
  • oncological diseases. The most common cause of the formation of red blood cells in the blood, differing in size and volume. Usually affects other hematopoietic sprouts.
  • heavy metal poisoning. Most often, the width of the distribution of erythrocytes changes with lead intoxication of the body.

All of these causes require competent and qualified treatment. Otherwise, all of them can cause significant harm to the body, even death.

Reasons for the decline

If a patient's RDW-CV is below normal, then all blood cells are the same size (i.e., there is no significant difference in cell volume).

If the distribution width of erythrocytes by volume is reduced, the most likely diagnosis is microcytosis, in which all formed erythrocytes are small and cannot adequately supply tissues with oxygen.

Thalassemia is one of the most common diseases accompanied by the synthesis of small erythrocytes and, accordingly, a decrease in the RDW norm. This disease is hereditary, and manifests itself as a violation of the synthesis of normal hemoglobin chains, the activity of which in relation to oxygen is lower. At the same time, the blood loses its ability to normal and adequate exchange of gases (the index of the ratio of oxygen and carbon dioxide is lowered), which as a result leads to a violation of the functions of internal organs.

Characteristic of this disease is a change in the morphological properties of erythrocytes with a decrease in their size, as well as the appearance of "target" erythrocytes, the activity of which is reduced. Clinically, the disease is characterized by a deformity of the skull, an increase in internal organs (especially the liver and spleen), as well as the appearance of icteric skin color.

Another, no less common disease, in which RDW becomes below normal, is the development of microspherocytosis. This disease is hereditary, and its relative frequency of occurrence does not exceed a tenth of a percent.

With its development, an increase in the number of small and spherical erythrocytes in the patient's blood is observed, and the RDW index is lower due to their short lifespan. At the same time, due to the inferiority of their membrane, the current of sodium ions inside the cell increases, which leads to intravascular death of erythrocytes and the development of hemolysis. Clinically, this is manifested by the development of a feeling of weakness, anemia, jaundice and disruption of the internal organs.

If the patient has any of these symptoms, then it is necessary to conduct a comprehensive examination of the whole organism as soon as possible.

The distribution index of erythrocytes is lowered: what does it mean and what to do? Decrease in RDW: pathology and norm

The erythrocyte distribution index (RDW) is very an important factor during a complete blood count. This indicator shows the size and shape of red blood cells.

Red blood cells realize the function of transportation, thereby assisting in the penetration of oxygen into all tissues and organs, while taking away toxins and carbon dioxide accumulated in cells. In the normal state, red blood cells are approximately the same size, which allows them to quickly stick together, forming blood clots.

The indicator of red blood cells in the blood can reflect the presence of pathological processes in the body, especially if the sizes of these cells vary significantly. Next, we will talk about the situations in which the red blood cell distribution index decreases, how it manifests itself and what it indicates.

Reduced RDW: norm and pathology

A person in good health has red blood cells of the same shape, density and color. In the event of a deviation, especially in the presence of autoimmune diseases or oncology, a failure occurs at the level of microcells, when young cells do not receive a certain number of components, which, in fact, slows down their performance. Thus, anemia occurs - a pathology during which the body does not receive the right amount oxygen, in other words, the metabolic function in erythrocytes is disturbed.

What does RDW mean in a blood test?

During a general blood test, the distribution index of erythrocytes is determined. If a specific disease is suspected, a blood test is prescribed to determine only this indicator.

Most often, the width of the distribution of erythrocytes by volume is determined in conjunction with the MCV index. This is the average volume of erythrocytes. This happens because these indexes (by number and volume) are closely related and help in determining the type of anemia.

It happens that the distribution index of erythrocytes is lowered. What does it mean? The thing is that for a qualitative judgment about the state of erythrocytes, not only their concentration in the blood is important, but also their shape. An increased distribution of erythrocytes is observed in 1 of the cases, but if the RDW index is lowered, which is much less common, we are talking about availability serious problems in the human body.

A blood test to determine the distribution index of erythrocytes can be carried out both during medical examinations (scheduled) and as prescribed, if there are suspicions of any deviations in the hematopoietic function. The analysis is carried out necessarily before surgery, during pregnancy and in childhood.

Why is it necessary to do an analysis on RDW?

It has already been said above that the distribution index of erythrocytes in the blood makes it possible to conduct a qualitative assessment of the composition of red blood cells, given their size.

But why is this necessary? The thing is that these cells are very similar to each other, which gives them the opportunity to replace each other or form blastulae. An increase in cell size entails an increased need for nutrition and, in addition, this means that their lifespan is reduced. All this directly affects total score red blood cells in the blood and human condition.

When a large number of red blood cells die, iron is released and there is more bilirubin, which affects the liver increased load, and as a result, it cannot process these substances.

The RDW index is directly related to and pathological process, during which the dimensions of red blood cells change (anisocytosis). This state is a complex chemical process that causes all blood cells to suffer.

How is it calculated?

The RDW indicator is calculated as a percentage, the norm of which is the limit from 11.5 to 14.8. The distribution index of erythrocytes is determined using a mathematical equation, which is the ratio of modified red blood cells and their total mass.

At present, laboratories use computer technology that allows you to calculate the percentage of deviation from the established norm. The results of the calculation are presented in the form of a histogram depicting a curve that indicates the likely changes in the size of red blood cells.

Normal performance

The norms of the erythrocyte distribution index depend on gender, age and the presence of certain conditions that occur in the human body. For children up to a year normal rate is 11.5-18.7%. AT one year old and older values ​​rush to the generally accepted norm of 11.5-14.5%.

For the female half of humanity, the upper limit shifts to 15.5%, because their hormonal levels change too often: during pregnancy, lactation, taking oral contraceptives, menopause.

For analysis, blood is taken on an empty stomach in the morning (until 9 am). It is very important that before this procedure a person does not take any medications, and also stays in a balanced internal state.

Raise RDW

The level of RDW in some situations is elevated. The most common cause of this pathology is iron deficiency anemia. The indicator can change at different stages of the development of pathology, which clearly reflects the histogram of erythrocytes:

  • The initial stage of the development of anemia is characterized by normal indices, but hemoglobin will be greatly reduced. This is the result of healthy functioning of the spinal cord.
  • The next stage of development in the histogram will show an increase in RDW. When there are problems with hemoglobin, indicators such as the average concentration and content of hemoglobin in the blood cell, the average volume of red cells decrease.

In the treatment of IDA, it is necessary to normalize the level of iron-containing protein concentration and its characteristics in human blood.

What do low scores mean?

Patients often ask what it means: "erythrocyte distribution index is lowered." Since the erythrocyte distribution index cannot be estimated without a volume indicator, it is necessary to familiarize yourself with all options for underestimated indicators with their relationship:

  1. RDW is low, and MCV is below average - indicates the presence of problems with the spleen and liver.
  2. RDW is lowered, and MCV is higher than the normal level - indicates the presence of oncological pathologies, mainly the development of bone marrow metastases.

The fact that the distribution index of erythrocytes RDW sd is lowered, with biological point vision, cannot, in principle, be observed. For this reason, most often the patient is offered to donate blood again, observing the following conditions:

  • stop smoking and drinking alcohol within 24 hours before blood sampling;
  • before the analysis, do not take any medications;
  • refuse to eat smoked and salty foods the day before.

In the case when the distribution index of erythrocytes RDW sd is really lowered, which is necessarily confirmed by deviations from the norm of the MCV indicator, this indicates the occurrence of certain pathologies. These include:

  • Hypochromic microcytic anemia - sometimes also called anemia. A condition in which irregularly shaped red blood cells die because they have no biological value in the body.
  • Malignant tumors - usually in this case we are talking about mastopathy, cancer bone marrow and lungs.
  • Hemolysis of red blood cells is the process during which red blood cells die before reaching their target. As a result, active hemoglobin is released.

The reasons

So, the distribution index of erythrocytes is lowered - what does this mean? There are several reasons that can lower the RDW:

  • Acute blood loss in trauma and pathological bleeding.
  • Frequent operations.
  • A metabolic disorder in which the food consumed is not completely digested.
  • Hormonal failure, which is most common in women.
  • Deficiency in the body of B vitamins and iron.
  • Blood diseases characterized by rapid destructive processes.

What measures to take?

A highly qualified doctor at the consultation will most likely ask the patient to take the test again, because the RDW indicator is almost never underestimated. Since this suggests that all cells are ideal in their parameters, and this, in principle, cannot be. If the indicator is confirmed upon re-analysis, then a complete study of the state of the body is carried out, paying attention to Special attention oncological examinations.

Preventive measures

prevent reduced rate RDW is possible subject to the following simple rules:

  • The diet should be balanced, which includes a lot of fresh fruits, lean meat and vegetables.
  • It is recommended to breathe fresh air as often as possible.
  • An active lifestyle will help prevent the RDW index from dropping.
  • It is very important not to miss scheduled medical examinations, during which serious deviations from the norm are most often detected that do not have external symptoms.

As a result, we learned that the distribution index of erythrocytes reflects their dimensions relative to each other and makes it possible to learn about their biological value. A decrease in the RDW is very rare, but if the distribution index of erythrocytes is low, this means that various pathologies are possible.

The index is calculated based on the results of a general blood test, but it can only be fully valid in conjunction with the MCV indicator, since they are closely interconnected.

The distribution width of erythrocytes is increased

Each of us in our lives has experienced laboratory research blood.

Blood consists of plasma, the percentage of which is 50-60, and individual cells - red blood cells, platelets (do you know what to do if platelets are low during pregnancy?), white blood cells, and others, whose share is a percentage. In the process of research, various components of the blood are determined, or rather, their number.

Erythrocytes are blood cells whose task is to:

  • maintaining an acid-base balance;
  • withdrawal from plasma of various amino acids;
  • isotonic support;
  • oxygen saturation;
  • removal of carbon dioxide from the cells and tissues of the body.

It's pretty clear that various etiologies violations of the quantitative content of erythrocytes in the blood lead to various diseases the human body as a whole. Main component erythrocyte - hemoglobin.

Blood analysis

When examining blood in laboratory conditions, regardless of its purpose, first of all, studies of the level of leukocytes are carried out, as well as hemoglobin saturation:

  • at elevated content leukocytes, blockage of small vessels can be observed,
  • with an insufficient number of red blood cells, oxygen starvation can occur.

In the analysis, there are such concepts as: the average volume of erythrocytes, the content of hemoglobin in one erythrocyte, the concentration of hemoglobin. Also important indicator is the width of the distribution of erythrocytes, whether it is increased.

Increased red blood cell distribution width

The width of distribution in a healthy person is a value equal to 11.5 to 14.5 percent. With an increase in this indicator, that is, with an increase in the width of the distribution, erythrocytes differ greatly from each other in size. The increased size of erythrocytes shortens their lifespan, which by itself negatively affects the total number of erythrocytes in the blood.

As you know, with a fairly large destruction of red blood cells, as a result of which a large amount of iron, the yellow pigment of bilirubin, is formed in the blood, which enters the liver for further processing. The liver, under this load, cannot fully cope with the processing of iron, which also adversely affects human health. Also, the width of the distribution of erythrocytes with an increase affects the work of the spleen, leading it to increase in size, due to the fact that the spleen removes “non-working” erythrocytes from the body and releases new ones into the blood.

Such increased functionality of the spleen can affect nearby organs. Due to a significant increase, the latter can crush the stomach and intestines. With pressure on the lung, the development of various kinds of diseases of the upper respiratory tract is also possible.

With an increased width of the distribution of erythrocytes, one can, first of all, judge a disease called "iron deficiency anemia". This disease is the most common among anemia. At different stages, the indicator of the width of the distribution of erythrocytes is not increased equally. In the initial stages of the disease, the density index may be normal, but the hemoglobin content index may be lowered.

With the development of the disease, the width of the distribution of erythrocytes increases, that is, individual erythrocytes increase in size. The content of hemoglobin in erythrocytes, on the contrary, decreases, sometimes to a critical level. Treatment of this type of anemia primarily consists in normalizing the level of hemoglobin and its characteristics. Treatment is mainly medical, with the use of drugs with great content gland.

With an increase in the width of the distribution of erythrocytes, the heterogeneity of erythrocytes is often noticed, that is, erythrocytes are observed in the blood that differ greatly in size. Also, the reasons for the increase in the width of the distribution of erythrocytes can be of various kinds. chronic diseases liver, lack of vitamin B12, various neoplasms, cancer diseases and other boards.

Symptoms of an increase in the width of the distribution of red blood cells

With the development of an increased width of the distribution of erythrocytes, various manifestations can be observed.

For example, since in this case there is a considerable effect on the liver and spleen, yellowness of the skin, an increase in body temperature may appear. As with any disease, sweating, loss of strength, drowsiness and fast fatiguability. On the part of the human nervous system, both excitations and, vice versa, more renounced states are possible. In any case, the symptoms cannot be specifically described, as changes in red blood cells affect many organs.

Consequently, a violation of the width of the distribution of erythrocytes can lead to diseases of a different nature and severity of the course, since the human body is a rather complex system, with a number of interconnected organs and systems. The abnormal functioning of one of them can lead to a malfunction of the body as a whole.

The distribution width of erythrocytes in a blood test

Many of us, donating blood for tests, only know in general terms what this study shows. Hemoglobin, sugar level, leukocytes, erythrocytes. But in laboratory conditions, not only the amount of various blood components is determined, but also their quality, saturation, volume and even shape. Few people know what the width of the distribution of red blood cells means. It's time to improve your horizons in the field medical examinations and expand knowledge in the analysis of clinical analyses.

One of the indicators to assess the state of erythrocytes is the width of the distribution of erythrocytes RDW. With the help of this erythrocyte index, the presence of red blood cells of different volumes in the blood, the area of ​​\u200b\u200btheir distribution and the range of difference between the largest and smallest erythrocytes are determined. Usually, blood cells are homogeneous and equal in volume, but over the years or the appearance of certain pathologies, a discrepancy is obtained between the cells. There are some diseases that can be found on early stage using the analysis of the width of the distribution of red blood cells RDW CV.

What is the RBC Distribution Width RDW?

Of course, the basis of blood is erythrocytes or red blood cells. That is why our blood is red. Red blood cells have very important responsibilities in the body: saturate it with oxygen, maintain acid and alkaline balance and isotonia, remove CO 2 (carbon dioxide) from organs and tissues, and much more. Similar functions are performed by hemoglobin, which is a significant part of the erythrocyte. Therefore, upon delivery clinical analysis blood, some erythrocyte indices are checked, one of them is the erythrocyte distribution width (RDW). This parameter represents the level of heterogeneity of red cells, as well as how different red blood cells differ from each other. RDW is measured with a special hematological device, the result is recorded as a percentage.

Normal RDW for an adult is considered to be 11.5-14.5%, and for children under 6 months old, the norm is set in the range of 14.9-18.7%, and after 6 months - 11.6-14.8%.

For example, if the distribution width of erythrocytes is increased, this means that the cells greatly outnumber each other in size, their life span is significantly reduced, and the total number of cells is disturbed. When the width of the distribution of erythrocytes is below normal, this indicates a slow blood formation and may indicate the presence of anemia (anemia) in any degree.

Any deviation from the norm can lead to various problems and diseases, by nature and severity, and are the basis for additional examination and identification of the cause. But, in any case, only a qualified, experienced specialist can make the only correct conclusion.

When lowered

If a reduced RDW is detected in a blood test, then most likely you will be sent for a retake of the analysis, since the analytical device can only record normal and high levels. This situation is extremely rare, and basically the doctor states the development of anemia. However, sometimes the RDW CV can be lowered due to:

  • oncology;
  • the occurrence of myeloma or leukemia;
  • destruction or damage of red blood cells with the release of hemoglobin (hemolysis).

The main reasons when the width of the distribution of erythrocytes by volume is below normal:

  • lack of iron in the body;
  • lack of certain vitamins;
  • large (prolonged) blood loss;
  • pathological erythrocyte decay.

At the first manifestations of anemia, a person begins to feel unwell, prone to fainting and shortness of breath, the skin becomes too pale. In this case, you need to consult a doctor for advice, especially if the width of the distribution of red blood cells is below the norm in a child.

The width of the distribution of erythrocytes by volume is increased

The condition when the RDW is significantly higher than normal is called anisocytosis. As already mentioned, this is not an independent disease, but only a factor of some specific cause.

When the distribution width of erythrocytes by volume is increased, this means that red blood cells are different in their diameter, there are normocytes with a diameter of 7-9 microns, microcytes - up to 6.9 microns, macrocytes - from 8 microns, and megacytes - from 12 microns.

Erythrocyte anisocytosis can be of 3 degrees of severity:

  • I degree - when 30-50% of all blood cells have a different size;
  • II degree - in % of erythrocytes the diameter is changed;
  • III degree - more than 70% of all blood cells are transformed.

When the relative width of the distribution of erythrocytes by volume is increased, red blood cells live very long. short life, and with a large number of destroyed erythrocytes, a lot of iron and bilirubin accumulate. These substances subsequently enter the liver for modification and processing. Thus, the organ is heavily overloaded, so it does not perform its other functions well.

In addition, the spleen increases in size, which is engaged in getting rid of destroyed blood cells and replenishing new ones. In such a situation, the load on the spleen is simply enormous, so much so that the nearest adjacent organs, such as the stomach or intestines, may suffer.

The main reasons for the increased width of distribution of erythrocytes by volume:

  • acute liver diseases;
  • Deficiency of vit. A and B12 ;
  • iron deficiency and folic acid deficiency anemia;
  • oncological formations;
  • alcoholism;
  • leukocytosis;
  • hemolytic crisis.

Also, the width of the distribution of erythrocytes by volume above the norm is found in lead poisoning, diseases of the heart and blood vessels, and bone marrow metaplasia.

Symptoms of anisocytosis

because of negative impact on the liver and spleen, a patient with a similar phenomenon may experience yellowish color skin.

Another obvious sign is excessive sweating, fatigue and drowsiness, weakness and loss of strength, inability to perform long-term work.

The nervous system can also be shaken, a person can be too excited in places, or, on the contrary, seem indifferent and aloof.

In addition, often the patient has a rapid heartbeat, even in a state of calm, shortness of breath.

Eyeballs, skin and nails become unhealthy pale.

Treatment of such a condition usually comes down to eliminating the factors and causes of the appearance of cells of different sizes. Sometimes, it is enough to make a little lifestyle change, stick to the recommended diet and stop taking medications that contribute to the fall of vit. B 12 in the body so that the red blood cells return to normal.

Why is the distribution width of erythrocytes increased and treatment

Deviation of indicators from the norm indicates pathological processes occurring in the body. During the analysis, it can be revealed that the width of the distribution of red blood cells is increased. What does it say?

The components of blood are:

red bodies

Red blood cells are blood cells that stain it in a characteristic color. In healthy people, they are the same in volume and shape. Red cells perform the following tasks:

  • ensuring a normal acid-base environment;
  • oxygen saturation;
  • isotonic support;
  • removal of carbon dioxide from tissues.

The proper functioning of red cells depends on their volume in the blood.

Violation of the level of red blood cells is caused by the development of any pathology in the body.

The main constituent of red cells is hemoglobin.

Blood test

In a laboratory blood test, first of all, the number of leukocytes and the level of hemoglobin are established:

  • with an increased leukocyte count, there may be a blockage of small vessels;
  • with insufficient volume of red cells, oxygen deficiency is observed.

An important indicator of a blood test is the width of the distribution of erythrocytes. In healthy people, it is in percentage terms from 11.5 to 14.5. With an increase in this level, erythrocytes globally differ in size from each other. Increased parameters of red cells reduce their vital activity, which in itself negatively affects the total number of red blood cells.

With a sufficiently large-scale destruction of red cells, a large amount of iron, the yellow pigment of bilirubin, is concentrated in the blood, which enters the liver for further processing. Under the influence of such a load, she cannot fully cope with this, which negatively affects the well-being of a person, his health. Also, with an increase in the distribution width of red cells, negative impact on the functioning of the spleen. It increases in parameters due to the fact that it cleanses the body of "broken" red blood cells, and throws new cells into the blood.

Such activity of the spleen can adversely affect neighboring organs. With its increase, there is pressure on the intestines, stomach, lungs.

When an increase in the width of the distribution of red cells is determined, then first of all, experts judge a pathology called "iron deficiency anemia". This disease is the most common. At different stages, the level of width is increased in different ways. On the initial stage pathological course the density coefficient may correspond to the norm, and the hemoglobin content may be reduced.

With the development of the disease, there is an increase in the width of the distribution of bodies, that is, some red blood cells become larger in parameters. The hemoglobin index in cells, on the contrary, falls, sometimes even to a critical level. Treatment of this type of pathology is associated with the normalization of its level. Basically, therapy involves the use of medications containing a large amount of iron.

An increase in RDW in adults, children, during pregnancy can occur when anemia develops, the body lacks vitamins, and there are liver pathologies.

If there is an increase in the width of the distribution of cells, heterogeneity of erythrocytes is often observed. In the blood there are bodies that differ significantly in size. Also, the factors of this pathological course can be various chronic diseases liver, vitamin B12 deficiency, any neoplasms, cancerous tumors And so on.

In an adult, a blood sample is taken from a vein in morning time on empty stomach. In a child, analysis is usually taken from a finger.

Symptoms

When the relative width of the distribution of erythrocytes increases, various symptoms may appear.

So, for example, yellowing of the skin is observed, since in this case a serious effect on the functioning of the liver and spleen, an increase in temperature is carried out. As with many other diseases, the patient's sweating increases, the person becomes drowsy, easily fatigued, and weak. Due to the effect on the nervous system, the patient experiences a frequent change of mood: arousal is abruptly replaced by renunciate behavior. In each situation, the symptoms cannot be accurately described, since changes in red blood cells affect many organs of a person.

From this it follows that a change in the width of the distribution of bodies sometimes causes pathologies of a diverse nature and severity of development, since the body is a rather complex system with a line of interconnected organs. The malfunctioning of any of them can cause a malfunction of the whole organism.

RBC Distribution Width (RDW)

A blood test can determine not only quantitative, but also qualitative composition blood. The size, shape, color and volume of cells are additional criterion for diagnosing diseases. Sometimes in the general analysis, in addition to red, white, flat cells RDW is indicated, which means the distribution of red blood cells in width.

What is RDW in a blood test?

The color of our blood is given by red cells - erythrocytes. They are disc-shaped, concave in the middle on both sides. They are produced by the red bone marrow. The composition of cells contains hemoglobin - a protein that takes part in metabolism. It binds oxygen in the lungs, then delivers it to the tissues.

Normally, all red blood cells have the same size, shape, color, so that if necessary, one cell can replace another and perform the same functions. In various diseases, some of the red blood cells increase in size. Large cells cannot pass into the narrow lumen of the capillaries, blood circulation is disturbed, so the body utilizes unnecessary elements.

RDW is an index that shows the ratio of healthy and enlarged red blood cells in diameter. 2 RDW indicators are determined:

  • RDW CV is the distribution of erythrocytes by size in percent;
  • RDW SD - determines the difference between the smallest and largest red blood cells.

Analysis on RDW

Analysis for RDW shows erythrocyte anisocytosis, that is, the presence of red cells of a non-standard size. In addition to normocytes in anisocytosis, there are:

  • Microcytes - their diameter is less than 7 microns;
  • Macrocytes - diameter from 8 to 12 microns;
  • Megalocytes - more than 12 microns.

When RBCs are very different in size from normocytes, anisocytosis is diagnosed. Depending on which cells predominate, microcytosis, macrocytosis, and a mixed state occur.

RDW is determined in the overall clinical analysis, which is carried out in planned during diagnosis or before surgery.

The value of the indicator needs to be known if anemia is suspected, differential diagnosis various kinds diseases, as well as to control the quality of treatment.

Blood is taken from a finger in the morning on an empty stomach. In the laboratory, the degree of decrease or increase in RDW is calculated. The laboratory assistant can do this manually or on a modern hematological analyzer. On the device, the study shows more accurate values, the result is determined faster.

When the level of anisocytosis is elevated, a retake for analysis with a histogram is required, since the width of the distribution of erythrocytes changes frequently and quickly.

Norm RDW in a blood test

The normal RDW value does not depend on age and sex differences in adults. In newborns and older children, this figure may normally be slightly higher than in adults.

RDW rate table in percent:

There are several degrees of anisocytosis:

  • I degree - a slight increase, large and small red blood cells are in the range of 30-50%;
  • II degree - moderate increase: from 50% to 70%;
  • III degree - a pronounced increase in anisocytosis: more than 70%;
  • IV degree - almost all erythrocytes are changed.

Analyzers count the number of red cells different size per 1 µl of blood, as well as a deviation in size by degrees. In addition to RDW - the width of the spread of erythrocytes in diameter, - a study is used on MCV - the distribution of red cells by volume. Knowledge of the second indicator is necessary for a more accurate diagnosis.

Increased RDW

An increase in the RDW index from the normal value indicates that diseases are present in the body. If the distribution width of erythrocytes is increased, this means that most of the red cells have deformed and changed. The life span of such cells is reduced, which affects the total number of red blood cells in the body: the indicator goes down.

RDW is elevated in a blood test for the following diseases:

  • Anemia with iron deficiency;
  • Anemia with a deficiency of vitamin B12 and folic acid;
  • Hemolytic anemia - a decrease in hemoglobin occurs due to the premature destruction of red blood cells;
  • Chronic liver diseases;
  • Oncology with liver metastases;
  • Leukemia;
  • blood transfusion;
  • Alcoholism;
  • lead intoxication;
  • Alzheimer's disease - neurodegenerative changes with loss of short-term and long-term memory.

A change in the distribution of red cells along the diameter may also indicate cardiovascular pathology and the development of IS of the heart.

RDW in the blood test is lowered

A decrease in the width of the distribution of erythrocytes below the norm practically does not occur. With some types of anemia, it can remain within normal values:

  • Aplastic anemia - stem cells of the bone marrow are affected, because of this, blood cells do not mature and grow;
  • Posthemorrhagic anemia - after bleeding;
  • Anemia in chronic diseases;
  • Spherocytosis - red cells take the form of a ball and quickly collapse (a type of hemolytic anemia);
  • Thalassemia is a hereditary disease in which red blood cells are deformed, it is dangerous to develop a hemolytic crisis;
  • Sickle cell anemia - genetic disease blood, a defect in cells does not allow binding hemoglobin in full, cells are elongated in shape and resemble a sickle, which is fraught with blockage of blood vessels throughout the body.

Since there are a great many different types of anemia, in medicine, the RDW index plays a crucial role in diagnosing diseases. The indicator is also determined to monitor the effectiveness of treatment in order to make changes to treatment measures, if necessary, while preventing complications and serious consequences.

Distribution width of erythrocytes by volume

The most accessible and highly effective diagnostic method in modern medicine considered a clinical blood test. Such a study is prescribed in almost all cases of a person applying for medical care at various ailments. Any changes in the blood composition allow the specialist to suspect the development of various diseases at an early stage of their development. In addition, with the help of the analysis, it is possible to identify the causes of the appearance of a particular symptomatology. During a blood test, the laboratory evaluates the parameters of absolutely all blood elements, of which there are more than 20 today. Among them is an important indicator of RDW in a blood test - the erythrocyte index. The abbreviation stands for "the width of the distribution of erythrocytes by volume."

RDW in a blood test

Erythrocytes are red blood cells that give blood its red color. These cells provide the organs and tissues of the body with oxygen. In people in good health, these cells do not differ in shape, color, or volume. It is important to know that the proper functioning of blood cells does not depend on their size, but on volume. With age, however, red blood cells decrease slightly in volume, which causes a difference to form between cells. Differences may also appear in some pathological processes or in anemia. If different red blood cells are found in the human body, then experts call this condition “erythrocyte anisocytosis”.

Anisocytosis of erythrocytes and its degree is investigated by RDW analysis, which shows the degree of heterogeneity of erythrocytes in size.

So, if the width of the distribution of erythrocytes exceeds normal values, then this condition indicates that the size of erythrocytes is greatly increased, and their life cycle decreases. In such a condition, the normal content of red blood cells in human blood is disturbed. If the RDW-cv is lowered, then there is a reason to suspect a condition in the patient in which blood formation occurs more slowly than expected, namely any degree of anemia (anemia).

The RDW-сv index shows the difference in erythrocyte volume from the average.

The RDW-sd index indicates how strongly the cells differ in volume (relative distribution width).

Analysis

An analysis for RDW-cv is carried out during a clinical (general) blood test. As a rule, such an analysis is prescribed upon admission to hospital for treatment, during a visit to a general practitioner, as well as in the diagnosis of various diseases.

Such a study plays the most important role in preparing the patient for any kind of surgical intervention.

Preparation for analysis

In order for the analysis to show truly true results, before donating blood, you need to follow some rules:

  • blood is given only in the morning;
  • before donating blood, the patient is forbidden to consume any food and liquids (except for mineral non-carbonated water);
  • 24 hours before the analysis, it is necessary to limit physical and emotional stress;
  • when taking any medications, notify the specialist in advance.

What can affect the result?

AT recent times blood is examined using special medical equipment, which has proven itself from a very good side. However, this kind of "machines" rarely, but malfunctions occur. Therefore, there is always a risk of error in the correctness of the study. The best and most reliable way of analysis is to count blood elements and decipher the indicators manually. But, in view of the fact that this method is laborious, it has long been abandoned in most laboratories.

If the result of the RDW-cv analysis does not correspond to the norm, as a rule, a re-examination is prescribed.

The distortion of the results of the analysis on the width of the distribution of erythrocytes by volume may be affected by non-compliance with the rules for preparing for blood sampling.

So, for example, if a patient, especially a child, was nervous before donating blood or spent time physically actively, then there is a possibility of inaccuracy in the indicators.

How is it carried out

To study RDW in a blood test (cv and sd), a biomaterial is taken from a vein. Patients childhood, if it is impossible to take blood from a vein, they take capillary blood - from a finger. The blood sampling procedure is relatively painless, however, after the manipulation, some people notice the formation of a small hematoma at the site of a skin puncture with a needle. Such a manifestation may indicate an increase in the level of hemoglobin or sugar.

Norm

The norm of indicators, both for men and women, varies between 11-15%.

If the distribution width of erythrocytes deviates in any direction by at least 1%, then such a deviation is considered pathological.

Patients younger age the norm of the indicator "the width of the distribution of erythrocytes by volume" varies depending on age:

The interpretation of the analysis data is carried out only by an experienced specialist.

Increased values

Enlarged cells have a lower life cycle, which negatively affects the total number of these blood cells.

With significant destruction of red blood cells in the body, the formation of a large amount of iron and bilirubin begins. The latter enters the liver for processing, and its large volume leads to a significant load on the hematopoietic system.

In addition, an increase in RDW-cv / sd sometimes leads to an increase in the size of the spleen, as well as to a load on adjacent internal organs(an enlarged spleen puts pressure on the organs of the digestive system).

The RDW-cv norm is exceeded, as a rule, for several reasons, among which:

  • chronic pathologies of the liver;
  • vitamin B12 deficiency;
  • oncological diseases, malignant neoplasms.

Non-pathological causes include:

Reduced values

Lowering the rate of RDW-cv/sd is very rare.

If the interpretation of the blood test showed that the width of the distribution of red blood cells is lower than the established norm, the patient must definitely donate blood again. If the second test also indicated a decrease in RDW, then the attending physician must determine for which of the reasons this condition arose:

  • extensive blood loss;
  • iron deficiency in the patient's body;
  • avitaminosis;
  • destruction of red blood cells;
  • leukemia, myeloma;
  • malignant neoplasms;
  • hemolysis.

In order to maintain normal health, each person must lead healthy lifestyle life and listen to your body. If you have any signs of feeling unwell, you should consult a doctor.

It is important to remember that the timely detection of any disease increases the chances of a speedy recovery.

What to do when the erythrocyte distribution index is lowered?

One of the important factors in conducting a complete blood count is the distribution index of erythrocytes (RDW). It…

Quite an important indicator, according to the values ​​of which one can judge the presence of a number of diseases. This analysis allows you to find out the state of red blood cells in the blood by their volume. The best option would be to have red blood cells of the same volume, since the volume (and not the size) of red blood cells depends on the efficiency of oxygen supply to tissues and organs.

However, due to various circumstances, erythrocytes can differ in volume from each other. So, in the results of a blood test, numbers are interesting that determine the presence of erythrocytes of various sizes and the difference between them.

Note that anisocytosis is pathological change sizes (volume) of erythrocytes. If 7 - 7.5 micrometers is considered to be the norm, then macrocytes (large cells) with sizes from 8 to 12 micrometers are considered deviations. Small deviations from the norm are not critical. The ratio between normal and altered erythrocytes is considered to be the norm as 5:1.

Attention. Clinically, anisocytosis can manifest as anemia, heart failure, and shortness of breath.

And just RDW in the analysis shows the order of violation of the distribution of erythrocytes in size.

It should be emphasized that the percentage width of the distribution of erythrocytes includes two markers:

  • RDW-CV is an indicator of the number of cells of different volumes, i.e. the severity of such a manifestation as anisocytosis.
  • RDW-SD - using this indicator, the difference between the sizes of red blood cells is assessed - from the smallest to the most pronounced.

In what cases is the analysis carried out

Under ideal conditions, even in normal outpatient conditions, when taking blood for a general clinical analysis, such an indicator as RDW and MCV must be indicated. Unfortunately, this often does not happen, and these indicators can significantly help in the diagnosis and early detection many diseases.

This study provides assistance in case of suspicion of:

  • Lack of iron, cyanocobalamin, folic acid in the body.
  • For the differential diagnosis of thalassemia from iron deficiency anemia.
  • Assessment of the state of the body oncological processes and pathology of the cardiovascular system.

The main symptoms to look out for and the doctor should order a blood test for RDW are:

  • Hyperthermic syndrome, especially prolonged. Without pronounced external signs of any disease.
  • Malaise.
  • Fatigue even after a good sleep.
  • Sweating day and night.
  • Drowsiness.
  • Unstable mood.
  • In some cases, the skin acquires a yellow tint.

How is the study going

For research in an adult, blood is taken from a vein on any arm. The analysis is carried out on an empty stomach. In young children, material can also be taken from a finger.

The result of the analysis is transformed into a histogram, according to which the results are evaluated. In the case of indicators within the normal range, the data are considered negative. If the manipulations revealed an increase in RDW, then the analysis is considered positive.

In some cases, the results of the study may be false positive, since the blood of a healthy person may contain red blood cells that have changed in shape and size. For this reason, it is recommended to use the Price-Jones curve in the process of interpreting the results.

Deciphering and meaning of the RDW indicator in the general blood test

For the correct interpretation of the obtained data, it is necessary to take into account the MCV indicators. The main goal in this case is the difference between the types of microcytic anemias.

RDW indicators in a blood test are the most important characteristic of the state of red blood cells. The ratio between red blood cells of different sizes in the blood can indicate a large number of diseases up to the development of malignant neoplasms.

To adequately characterize the indicators, it must be remembered that the RDW index can change rapidly, since it is not a constant value.

In general, in any study of a general blood test, the RDW index is to be calculated, since it is he who will fully characterize the state of the whole organism as a whole.

When determining the overestimated indices of the index, it is necessary to prescribe additional examinations, based on the main pathology of the patient.

In the case of increased indicators, it is necessary to look for more serious reasons to determine the development of formidable diseases at the very beginning of their development.

Relationship with MCV


With a change in the RDW-CV in the blood, an increase in the MCV will be observed.

Unlike CV, RDW-SD is independent of MCV levels.

An analysis of such indicators as RDW and MCV allows for a qualitative analysis of the state of the blood, as well as the nature of the pathological process, but which the blood gave a reaction.

Norm RDW

The indicators of a healthy person are as follows:

  1. Adults - from 11.5 to 14.5%.
  2. Children under 6 months - from 14.9 to 18.7%.
  3. Children older than 6 months - from 11.6 to 14.8%.

Reduced and elevated levels

The situation in which the RDW is elevated, that is, we have more red blood cells than we need, is quite dangerous. The fact is that one of the main disadvantages of macrocytes is their shortened lifetime. In itself, this is bad, because you need to somehow maintain the total number of red blood cells in the norm.

But more importantly, the number of simultaneously decaying red cells increases and, as a result, the flow of released iron and bilirubin increases. This increased flow begins to load the liver, which is now overworked.

In addition, some of the macrocytes in their diameter are not able to squeeze through the diameter of the capillaries, and the spleen is connected to their utilization. The load on it leads to its increase in size, and the spleen begins to put pressure on the intestines and stomach. Surrounding tissues and organs may be affected.

An increase in RDW values ​​of more than 15% indicates the development of pathological conditions in the body. Most often, RDW is elevated when:

  1. Combination with high rates MCV with increased RDW - liver damage with alcoholism, hemolytic anemia, megaloblastic anemia, vitamin A hypovitaminosis.
  2. Combination with low MCV with elevated RDW - low level hemoglobin, iron deficiency states, the most initial manifestations thalassemia.
  3. Combination with normal MCV with elevated RDW - manifestation of iron deficiency anemia, a decrease in vitamin B12 and / or folic acid, which leads to macrocytic anemia.

A decrease in RDW below 10.2% occurs in the presence of the following pathological processes in the body:

With normal RDW, accompanied by a decrease in MCV, they talk about:

  • Frequent blood transfusions, in which there is a dissociation in the formation and presence shaped elements blood.
  • Severe thalassemia.
  • Hemorrhagic processes due to chronic blood loss, to which the human body does not react at the onset of the disease with any external manifestations.
  • Removal of the spleen due to traumatic injuries- in this case, there is a sharp redistribution of blood cells, as well as a delay in the formation of blood elements due to the absence of one of the important organs of hematopoiesis.
  • Malignant neoplasms in which inhibition of cell growth of the blood system occurs.
  • Conducted chemotherapy, where, as in the course of chemotherapeutic treatment, suppression of the cellular elements of the blood system is observed.
  • development of myelodysplasia.

Important! Very often, the debut of various diseases is missed due to insufficient diagnosis.

A timely, complete, and most importantly competent study, first of all, of blood parameters will tell the doctor about many changes in the human body. This will not allow you to miss the onset of many diseases, even such as malignant neoplasms of various localization.

The distribution width of erythrocytes or RDW, as this indicator is usually indicated in analyzes, allows you to evaluate not only the number of erythrocytes in the blood, but also the range of their distribution, as well as sizes. From the largest to the smallest and how they differ from each other. As a rule, identical blood cells are approximately equal in volume. And red blood cells are no exception. However, some pathologies violate this balance, and a discrepancy may appear between them, sometimes quite significant. With the RBC Distribution Width Index or RDW, some diseases can be detected at a very early stage when there are no other signs.

Erythrocytes are red blood cells that are the basis of blood. They contain hemoglobin, which is an oxygen transporter throughout the body, acid-base balance blood, remove carbon dioxide from cells and perform other important features. That is why special attention is paid to red blood cells when analyzing blood - they are studied and compared using several different indices. In particular, the distribution width of erythrocytes is measured using a special hematological device that captures the impulses that transmit erythrocytes. The stronger these impulses, the larger the erythrocytes and vice versa. The measurement result is recorded as a percentage or in femtoliters - fl.

RBC Distribution Width (RDW). Result interpretation (table)

The erythrocyte distribution width test is a mandatory component of a clinical blood test. This index is necessary in order to correctly interpret the results of the study and be able to diagnose anemia in time, while at the same time differentiating between them. The distribution width of erythrocytes - RDW - is necessarily compared with their average volume - MCV, since it can often be within the established norm, while the erythrocytes themselves turn out to be too large or, conversely, too small, which in itself indicates the presence of a pathology .

Blood is taken from a vein in adults and from a finger in children. In some cases, a hematological smear is used, but such an analysis often produces incorrect results.

The norm of the width of the distribution of erythrocytes in ordinary people and pregnant women:


If the red blood cell distribution width (RDW) is increased, what does this mean?

If the distribution width of erythrocytes exceeds 14.5%, this indicates that the sizes of red blood cells differ significantly from each other. There may be several options here. First of all, as already mentioned, it is also necessary to estimate the value of the average volume erythrocyte MCV, that is, the size of the average space that each individual erythrocyte occupies. If this indicator is also overestimated, then this may indicate the following pathologies:

  • liver diseases - this organ is responsible for removing harmful toxins from the body, at the same time it synthesizes important chemical compounds and performs various other functions,
  • hemolytic anemia - pathological condition, in which red blood cells are destroyed much earlier than their normal lifespan,
  • deficiency of vitamin B12 or folic acid.

If the RDW index is increased, and the MCV index is decreased, then the reasons for this phenomenon may be as follows:

  • iron deficiency anemia - due to iron deficiency, an insufficient amount of hemoglobin is produced in the body,
  • thalassemia is a blood disease in which the synthesis of elements necessary for the production of hemoglobin is disrupted. At the same time, erythrocytes are fragmented (break up into smaller parts), which leads to a decrease in their average size, while the width of the distribution of erythrocytes remains high.

If the RDW index is elevated, and the MCV remains within the normal range, then this may indicate a deficiency of folic acid or vitamin B12. Or - about the initial stage of iron deficiency anemia.

An increased level of the width of the distribution of erythrocytes indicates that the life span of erythrocytes is shortened, they are destroyed, excess bilirubin and iron are released into the blood. This overloads the liver and prevents it from performing its main functions, and also leads to an increase in the spleen, which has to work in emergency mode in order to utilize the remnants of destroyed red blood cells. This often leads to damage to the organs closest to it - the intestines and stomach. Due to problems with the liver and spleen, patients with elevated red cell distribution width often have an unhealthy yellowish skin tone.

If the distribution width of red blood cells (RDW) is reduced, what does this mean?

If the distribution width of erythrocytes (RDW) is below 10.2%, this indicates that the red blood cells differ slightly from each other in size. There are two main reasons for this phenomenon:

  • macrocytic anemia is a blood disorder in which there is a shortage of red blood cells. They are synthesized, but their sizes are too large,
  • microcetic anemia is a blood disorder in which only abnormally small red blood cells are synthesized.

In both cases, red blood cells are almost the same size, which leads to low rates RDW.

Other reasons why the norm of the width of the distribution of red blood cells decreases:

  • oncological diseases,
  • myelosis or lymphoma
  • destruction of red blood cells or their damage and the release of hemoglobin,
  • deficiency of certain vitamins in the body,
  • iron deficiency,
  • massive blood loss.

However, it must be said that similar situation is quite rare and is usually the result of a laboratory error.

In the process of research, various components of the blood are determined, or rather, their number.

Erythrocytes are blood cells whose task is to:

  • maintaining an acid-base balance;
  • withdrawal from plasma of various amino acids;
  • isotonic support;
  • oxygen saturation;
  • removal of carbon dioxide from the cells and tissues of the body.

It is quite clear that, of various etiologies, disturbances in the quantitative content of red blood cells in the blood lead to various diseases of the human body as a whole. The main component of the erythrocyte is hemoglobin.

Blood analysis

When examining blood in the laboratory, regardless of its purpose, first of all, studies of the level of leukocytes are carried out, as well as hemoglobin saturation:

  • with an increased content of leukocytes, blockage of small vessels can be observed,
  • with an insufficient number of red blood cells, oxygen starvation can occur.

In the analysis, there are such concepts as: the average volume of erythrocytes, the content of hemoglobin in one erythrocyte, the concentration of hemoglobin. Also an important indicator is the width of the distribution of erythrocytes, whether it is increased.

Increased red blood cell distribution width

The width of distribution in a healthy person is a value equal to 11.5 to 14.5 percent. With an increase in this indicator, that is, with an increase in the width of the distribution, erythrocytes differ greatly from each other in size. The increased size of erythrocytes shortens their lifespan, which by itself negatively affects the total number of erythrocytes in the blood.

As you know, with a fairly large destruction of red blood cells, as a result of which a large amount of iron, the yellow pigment of bilirubin, is formed in the blood, which enters the liver for further processing. The liver, under this load, cannot fully cope with the processing of iron, which also adversely affects human health. Also, the width of the distribution of erythrocytes with an increase affects the work of the spleen, leading it to increase in size, due to the fact that the spleen removes “non-working” erythrocytes from the body and releases new ones into the blood.

Such increased functionality of the spleen can affect nearby organs. Due to a significant increase, the latter can crush the stomach and intestines. With pressure on the lung, the development of various kinds of diseases of the upper respiratory tract is also possible.

With an increased width of the distribution of erythrocytes, one can, first of all, judge a disease called "iron deficiency anemia". This disease is the most common among anemia. At different stages, the indicator of the width of the distribution of erythrocytes is not increased equally. In the initial stages of the disease, the density index may be normal, but the hemoglobin content index may be lowered.

With the development of the disease, the width of the distribution of erythrocytes increases, that is, individual erythrocytes increase in size. The content of hemoglobin in erythrocytes, on the contrary, decreases, sometimes to a critical level. Treatment of this type of anemia primarily consists in normalizing the level of hemoglobin and its characteristics. Treatment is mainly through medication with the use of drugs with a high iron content.

With an increase in the width of the distribution of erythrocytes, the heterogeneity of erythrocytes is often noticed, that is, erythrocytes are observed in the blood that differ greatly in size. Also, the reasons for increasing the width of the distribution of erythrocytes can be various kinds of chronic liver diseases, lack of vitamin B12, various neoplasms, cancers and other conditions.

Symptoms of an increase in the width of the distribution of red blood cells

With the development of an increased width of the distribution of erythrocytes, various manifestations can be observed.

For example, since in this case there is a considerable effect on the liver and spleen, yellowness of the skin and an increase in body temperature may appear. As with any disease, sweating, loss of strength, drowsiness and fatigue are manifested. On the part of the human nervous system, both excitations and, vice versa, more renounced states are possible. In any case, the symptoms cannot be specifically described, as changes in red blood cells affect many organs.

Consequently, a violation of the width of the distribution of erythrocytes can lead to diseases of a different nature and severity of the course, since the human body is a rather complex system, with a number of interconnected organs and systems. The abnormal functioning of one of them can lead to a malfunction of the body as a whole.

The distribution width of erythrocytes (RDW index): what is it, the norm, increased and decreased

To determine different populations of red blood cells, an indicator (erythrocyte index) is used - the width of the distribution of erythrocytes - RDW or the degree of erythrocyte anisocytosis, which is included in the list of all components of the general blood test (CBC), that is, this parameter is usually not assigned on its own and not tested in the laboratory.

So what does such an erythrocyte index as RDW mean, what information does it carry to specialists and why is it used?

Distribution of erythrocytes by volume

If we examine under a microscope the red blood cells present in the blood of a patient suffering from a certain hematological pathology, we can find that the erythrocytes (Er) are not all the same in volume. Among all non-nuclear biconcave forms, there may be cells that differ significantly in size from normal erythrocytes:

  • Large cells - macrocytes;
  • Just giants - megalocytes;
  • Lilliputian cells, which are called microcytes.

And here it is not necessary to be a specialist in this field in order to understand that red blood elements that have changed their volume will not be able to fully perform their physiological functions (transfer of oxygen and nutrients, regulation of water-salt metabolism and acid-base balance, participation in blood coagulation, etc. .), which, of course, will affect the overall health of the body.

Meanwhile, one should not attach too much importance if ugly forms are present in single copies, it is another matter if they claim an equal position with normal erythrocytes. In order to find out how many in the general population of erythrocytes there are bizarre shapes characteristic of a particular type of anemia, and calculate the width of the distribution of erythrocytes (erythrocyte index RDW).

Many laboratory diagnostic physicians and hematologists take RDW as a coefficient of variation, indicating how much the average red blood cell volume (MCV) deviates from the generally accepted norm, and calculate it using the formula:

where SD denotes the standard deviation of the mean volume of red blood cells, and the MCV index corresponds to their mean volume.

Is it always possible to believe the norm?

The range of normal values ​​of the distribution of erythrocytes by volume varies within 11.5 - 14.5% (in children under six months, the norm, in general, differs markedly and ranges from 14% to 18.7%, although from 6 months the values ​​​​of the indicator are already begin to aspire to the norm of adults).

An elevated RDW in a blood test indicates the degree of heterogeneity (heterogeneity) of red blood cell populations or indicates the presence of several blood cell populations in the sample, which occurs, for example, after a recent blood transfusion.

It is hardly possible to use the term “reduced RDW value” when calculating the width of the distribution of erythrocytes, since this option reflects, as it were, the norm, and therefore cannot be taken as a laboratory indicator characterizing some phenomenon unusual for these blood elements. The less unnatural forms (due to an increase or decrease in volume) of erythrocytes in the blood, the more representatives of the population for this trait are within the normal digital values. And yet, if this happens (RDW - lowered), then, most likely, the analyzer made a mistake, and in order to correct this oversight, the patient will have to provide a finger for a puncture again, and the laboratory staff will have to calibrate the device.

In addition, it should be taken into account that RDW, which is within the normal range, is not always proof of complete health, because in some cases, the distribution of red blood cells by volume is not increased, and clinical manifestations and laboratory tests confirm the presence of the disease (anemia).

Increased RDW

An increased index is quite a suitable indicator even for the differential diagnosis of certain types of anemia, it allows you to distinguish between their forms:

  1. Megaloblastic and macrocytic, a typical representative is B12 / folic / -deficiency anemia. In the blood test: hyperchromia, the average volume of Er is above 160 fl, the cell diameter is more than 12 μm, RDW is increased (anisocytosis), different forms of erythrocytes (poikilocytosis);
  2. Normocytic: aplastic anemia, as well as anemia caused by chronic pathology (tuberculosis, pyelonephritis, collagenoses, liver disease), a malignant process, or caused by dysfunction of the endocrine system;
  3. Microcytic (iron deficiency anemia, in the blood test: hypochromia, anisocytosis towards microcytosis).

True, in such cases, in addition to RDW, the diagnosis also relies on another erythrocyte index - MCV, which characterizes a red blood cell as a normocyte (at 80 x / l - 100 x / l or 80 - 100 femtoliters), microcyte (at - below 80 fl), macrocyte (if the average volume is more than 100 fl).

In addition, when testing blood samples in order to calculate the values ​​of erythrocyte indices (including RDW), it is very important to compare the results obtained with the histogram of erythrocytes, which, after completing their work, is usually issued by modern hematological systems with software.

Thus, an increased RDW with values ​​of the mean erythrocyte volume (MCV) above 100 fl may indicate the following pathological conditions:

  • IDA (iron deficiency anemia) - the most common anemic condition (IDA accounts for up to 80% in the entire group of diseases of this kind)
  • Sideroblastic anemia (a heterogeneous group of hypochromic microcytic anemias);
  • Macrocytic and megaloblastic anemia;
  • Myelodysplastic syndromes, which are a hematological pathology that combines a group of heterogeneous diseases with characteristic signs of a decrease in the number of individual populations of blood cell elements (cytopenia) and a clonal disorder of hematopoiesis in the bone marrow (dysplasia). Myelodysplastic syndrome is characterized by a high risk of transformation into a malignant process;
  • Bone marrow metaplasia;
  • Metastases of malignant tumors in the bone marrow.

Obviously, for a certain range of pathological conditions, the calculation of the width of the distribution of erythrocytes has a very important diagnostic value.

Why is RDW a new indicator for patients?

Previously, until automated hematological systems entered the daily life of the laboratory service, the degree of anisocytosis was determined visually, when viewing a smear using optical equipment. And the distribution width of erythrocytes was not called RDW and was not calculated by a device designed for automatic hematological analysis. The calculation was carried out by a different method - using the Price-Jones curve, which, as it turned out later, did not coincide with the erythrocytometric curves performed by the “smart” machine with maximum accuracy, but it took a lot of effort and time for doctors and laboratory assistants to conduct the study. Now, having placed the sample in the "smart" apparatus, no one asks him one question - to work only on a separate test. The analyzer simply calculates everything that is provided for by the program and is embedded in it, so patients began to see new indicators, which were not even mentioned when processing samples manually.

And such studies were previously of interest mainly to hematologists to clarify the nature of anemia, who, if necessary, turned to the laboratory with a note in the direction: to conduct a morphological study of erythrocytes, calculate and present graphically (Price-Jones erythrocytometric curve) the ratio of the number of red cells with different diameters. Of course, not all blood samples were subjected to such testing, but only samples taken from specific patients. Now, in principle, nothing has changed, this indicator is likely to be of interest to a separate circle of specialists. Well, if RDW is present in the blood test, then patients have the right to ask questions.

Currently, an automatic hematology analyzer successfully copes with the calculation of RDW in a blood test, which quietly, quickly and efficiently solves the problem. And makes RDW everyone.

The relative width of the distribution of erythrocytes by volume is increased or decreased

As a result of blood sampling in order to exclude a particular disease in a person, doctors in the laboratory carry out necessary research to identify pathologies in the collected plasma and its constituent cellular elements in the form of erythrocytes, leukocytes and platelets. The described elements for the performance of their normal function are determined by typical sizes, volumes (CV) and shapes. Therefore, any change in these indicators can affect the vital activity and active functioning of cells and, as a result, lead to various changes in homeostasis. Therefore, in order to be able correct assessment described cells and an indicator was developed in the form of a certain index indicating the width of the distribution of erythrocytes (rdw).

Using such an erythrocyte index, it is possible to determine in the hematopoietic system the presence of red blood cells of different volumes, their distribution and the scale of differences between the largest and smallest described elements. Often, the so-called blood cells have a homogeneous structure, and a single volume is indicated, but over time or as a result of the emergence of certain pathologies in humans, some discrepancies may be observed between cells.

Moreover, in nature there are such diseases that can be determined at an early stage of their manifestation only thanks to a blood test for the width of the distribution of erythrocytes - RDW CV.

What determines the width of the distribution of erythrocytes

And so the term described is due to a certain index, the use of which makes it possible for physicians to obtain information about the actual distribution of blood cells of various sizes and shapes. That is, when deciphering this index, you can get information about the percentage of erythrocytes in the hematopoietic system - the size and volume of these cells, which can be increased or decreased.

In order to fill the existing blood cells with oxygen, blood particles need to have a secured passage even into the smallest vessels of the human body. That is why, both in physiological terms and in size, the described bodies must fit the so-called openings of the vessels.

If excessively large or very small described elements are formed in the hematopoietic system, this leads to all kinds of changes in the described structural units of the human body. As a result, a person has a need to designate the cellular component of plasma by using an indicator in the form of RDW CV.

How the study is carried out and what is the norm for the width of the distribution of erythrocytes

Blood for the calculated distribution of the described cells is taken for research in view of:

  • Planned analysis;
  • Necessary diagnostics of certain pathological phenomena;
  • Operable intervention in the human body;
  • The origin of the diverse etiology of anemia.

Just the same, the last described pathological conditions are a common indicator indicating the need for certain blood tests. Especially since state-of-the-art methods blood sampling from a person makes it possible to carry out any examination of the hematopoietic system quite quickly and with high quality, giving a correct assessment of the state of the erythrocytes themselves.

The results of the tests performed will be negative if the described indicators are normal, and positive if high level RDW. And only with a second examination, the physician will be able to explain to the patient the pattern and reasons for this increase, since it is impossible to establish a reliable diagnosis based on a single blood sampling. So, for example, after any operation, the described index is usually due to an increased level of RDW.

Blood for research can be taken from an adult patient from a vein, and from a child from a finger. When passing the analysis itself, the recommended last meal should be taken 7-8 hours before the study itself.

To determine the norm of the indicator, the following are taken into account: age, gender and certain physiological processes occurring in human body. For infants aged 0 to one year, an indicator ranging from 11.5 to 18.7% can be considered the defining value of the norm.

After the first year of life, the digital value of the index begins to approach the norm from 11.5 to 14.5%. For the representatives of the weaker sex, the upper indicator can shift and reach a digital value of 15.5%, as a result hormonal changes body:

  • During pregnancy;
  • During lactation;
  • When using contraceptive means;
  • In view of the beginning of the menopause.

Important! Blood sampling should be carried out on an empty stomach. Before the study, you can not use any drugs inside.

In the process of in-depth study of the features of the distribution index of the described cells, it is customary to consider the following two values ​​in the form:

  • RDW (SD) - an indicator that determines the standard type of deviation from the norm, is determined by femtoliters and indications of the quantitative difference between large and small cells;
  • RDW (SV) - indicates the existing differences in the volumetric value of the described elements and the established average indicators. It is revealed by the percentage correlation of cells that have succumbed to deformation to the mass of all erythrocytes.

Reasons for the increase

The described coefficient of blood cells is higher than normal with an increase in the percentage correlation between small and enlarged cells, in relation to the described elements having sufficient volume. Due to the so-called redistribution of iron-containing protein, which is the basis of blood cells, their smallest number begins to be synthesized in the body, which subsequently leads to the manifestation of various anemias, to anisocytosis - when the main part of the cells has characteristic differences from each other.

According to the foregoing, the main feature of such bodies is their sufficient size, as well as the period of life. As a result of their death, a decent amount of bilirubin is released, which has a very bad effect on all organs of the human body.

The coefficient that distributes blood cells by volume can be high, since there are:

  • Lack in the body of such components as iron, folic acid, vitamins belonging to group "B". Such a condition may, not without reason, give a chance for the development of such a disease as anisocytosis, in which there is an increase in this index of elements of the hematopoietic system;
  • Oncological diseases leading to the formation of red blood cells of various sizes and volumes in the hematopoietic system;
  • Intoxication with chemical elements in the form of the heaviest metals (which is, for example, lead).

All of the above signs of illness should be stopped when using professional therapy. Otherwise, they will seriously harm the body and lead a person to death.

Reasons for the decrease in the indicator

With RDW - CV below normal, the existing elements of the hematopoietic system are indicated by the same size without any differences in cell volume. With a reduced volume indicator under consideration, most often physicians diagnose a condition in the form of microcytosis, in which the elements present in the blood, indicated by small sizes, cannot fully saturate the tissues of the human body with oxygen.

Also, with a decrease in the indicator, a disease is often encountered, accompanied by the unity of the main elements of blood of small sizes, along with a reduced rate of RDW in the form of thalassemia. Which refers to diseases of a hereditary nature, and manifests itself as a violation of the processes of synthesis of iron-containing protein chains, with reduced activation in relation to oxygen. In light of this, plasma is no longer able to participate in the process of gas exchange in a normal and adequate way, which ultimately leads to a change in the functioning of existing organs in humans.

This disease is also characterized by ongoing changes in the morphological properties of blood cells, with inhibition of their growth and a decrease in activity. The clinic of this disease is due to the deformation of the human cranium, the growth of organs, such as the liver and spleen, as well as the icteric color of the skin.

Also, with a reduced ratio of similar blood cells, a disease called microspherocytosis, which is a hereditary ailment, can develop. When such a disease appears in the hematopoietic system, there is more than a nominal small size, a certain form of erythrocytes, along with a decrease in the RDW coefficient, due to their insufficient vital activity. As a result, intravascular cell death occurs and so-called hemolysis develops.

In such a state, a person feels weakness, anemia, a manifestation of jaundice, characteristic of this state, along with changes in the activity of all organs of the human body.

If any of the above symptoms occur, you should immediately seek medical help and, for your own safety, carry out complete examination the whole organism. Only in this way can one protect oneself, thereby preventing one or another disease that may already have arisen.

RBC distribution width (RDW) is normal (table). Red blood cell distribution width (RDW) increased or decreased - what does it mean

The distribution width of erythrocytes or RDW, as this indicator is usually indicated in analyzes, allows you to evaluate not only the number of erythrocytes in the blood, but also the range of their distribution, as well as sizes. From the largest to the smallest and how they differ from each other. As a rule, identical blood cells are approximately equal in volume. And red blood cells are no exception. However, some pathologies violate this balance, and a discrepancy may appear between them, sometimes quite significant. With the RBC Distribution Width Index or RDW, some diseases can be detected at a very early stage when there are no other signs.

Erythrocytes are red blood cells that are the basis of blood. They contain hemoglobin, which is an oxygen transporter throughout the body, maintain the acid-base balance of the blood, remove carbon dioxide from cells and perform other important functions. That is why special attention is paid to red blood cells when analyzing blood - they are studied and compared using several different indices. In particular, the distribution width of erythrocytes is measured using a special hematological device that captures the impulses that transmit erythrocytes. The stronger these impulses, the larger the erythrocytes and vice versa. The measurement result is recorded as a percentage or in femtoliters - fl.

RBC distribution width (RDW) is normal. Result interpretation (table)

The erythrocyte distribution width test is a mandatory component of a clinical blood test. This index is necessary in order to correctly interpret the results of the study and be able to diagnose anemia in time, while at the same time differentiating between them. The distribution width of erythrocytes - RDW - is necessarily compared with their average volume - MCV, since it can often be within the established norm, while the erythrocytes themselves turn out to be too large or, conversely, too small, which in itself indicates the presence of a pathology .

Blood is taken from a vein in adults and from a finger in children. In some cases, a hematological smear is used, but such an analysis often produces incorrect results.

Red blood cell distribution width (RDW) - the norm in ordinary people and pregnant women:

If the distribution width of red blood cells (RDW) is increased - what does it mean

If the distribution width of erythrocytes exceeds 14.5%, this indicates that the sizes of red blood cells differ significantly from each other. There may be several options here. First of all, as already mentioned, it is also necessary to estimate the value of the average volume of erythrocytes MCV, that is, the size of the average space occupied by each individual erythrocyte. If this indicator is also overestimated, then this may indicate the following pathologies:

  • liver diseases - this organ is responsible for removing harmful toxins from the body, at the same time it synthesizes important chemical compounds and performs various other functions,
  • hemolytic anemia - a pathological condition in which red blood cells are destroyed much earlier than their normal lifespan,
  • deficiency of vitamin B12 or folic acid.

If the RDW index is increased, and the MCV index is decreased, then the reasons for this phenomenon may be as follows:

  • iron deficiency anemia - due to iron deficiency, an insufficient amount of hemoglobin is produced in the body,
  • thalassemia is a blood disease in which the synthesis of elements necessary for the production of hemoglobin is disrupted. At the same time, erythrocytes are fragmented (break up into smaller parts), which leads to a decrease in their average size, while the width of the distribution of erythrocytes remains high.

If the RDW index is elevated, and the MCV remains within the normal range, then this may indicate a deficiency of folic acid or vitamin B12. Or - about the initial stage of iron deficiency anemia.

An increased level of the width of the distribution of erythrocytes indicates that the life span of erythrocytes is shortened, they are destroyed, excess bilirubin and iron are released into the blood. This overloads the liver and prevents it from performing its main functions, and also leads to an increase in the spleen, which has to work in emergency mode in order to utilize the remnants of destroyed red blood cells. This often leads to damage to the organs closest to it - the intestines and stomach. Due to problems with the liver and spleen, patients with elevated red cell distribution width often have an unhealthy yellowish skin tone.

If the distribution width of red blood cells (RDW) is reduced - what does it mean

If the distribution width of erythrocytes (RDW) is below 10.2%, this indicates that the red blood cells differ slightly from each other in size. There are two main reasons for this phenomenon:

  • macrocytic anemia is a blood disorder in which there is a shortage of red blood cells. They are synthesized, but their sizes are too large,
  • microcetic anemia is a blood disorder in which only abnormally small red blood cells are synthesized.

In both cases, red blood cells are almost the same size, which leads to low RDW.

Other reasons why the width of the distribution of red blood cells decreases:

  • oncological diseases,
  • myelosis or lymphoma
  • destruction of red blood cells or their damage and the release of hemoglobin,
  • deficiency of certain vitamins in the body,
  • iron deficiency,
  • massive blood loss.

However, it must be said that such a situation is quite rare and, as a rule, is the result of a laboratory error.

The distribution index of erythrocytes is lowered: what does it mean and what to do? Decrease in RDW: pathology and norm

The Red Blood Cell Distribution Index (RDW) is a very important factor during a complete blood count. This indicator shows the size and shape of red blood cells.

Red blood cells realize the function of transportation, thereby assisting in the penetration of oxygen into all tissues and organs, while taking away toxins and carbon dioxide accumulated in cells. In the normal state, red blood cells are approximately the same size, which allows them to quickly stick together, forming blood clots.

The indicator of red blood cells in the blood can reflect the presence of pathological processes in the body, especially if the sizes of these cells vary significantly. Next, we will talk about the situations in which the red blood cell distribution index decreases, how it manifests itself and what it indicates.

Reduced RDW: norm and pathology

A person in good health has red blood cells of the same shape, density and color. In the event of a deviation, especially in the presence of autoimmune diseases or oncology, a failure occurs at the level of microcells, when young cells do not receive a certain number of components, which, in fact, slows down their performance. Thus, anemia occurs - a pathology during which the body does not receive the right amount of oxygen, in other words, the metabolic function in red blood cells is impaired.

What does RDW mean in a blood test?

During a general blood test, the distribution index of erythrocytes is determined. If a specific disease is suspected, a blood test is prescribed to determine only this indicator.

Most often, the width of the distribution of erythrocytes by volume is determined in conjunction with the MCV index. This is the average volume of erythrocytes. This happens because these indexes (by number and volume) are closely related and help in determining the type of anemia.

It happens that the distribution index of erythrocytes is lowered. What does it mean? The thing is that for a qualitative judgment about the state of erythrocytes, not only their concentration in the blood is important, but also their shape. An increased distribution of erythrocytes is observed in 1 of the cases, but if the RDW index is lowered, which is much less common, we are talking about the presence of serious problems in the human body.

A blood test to determine the distribution index of erythrocytes can be carried out both during medical examinations (scheduled) and as prescribed, if there are suspicions of any deviations in the hematopoietic function. The analysis is carried out necessarily before surgery, during pregnancy and in childhood.

Why is it necessary to do an analysis on RDW?

It has already been said above that the distribution index of erythrocytes in the blood makes it possible to conduct a qualitative assessment of the composition of red blood cells, given their size.

But why is this necessary? The thing is that these cells are very similar to each other, which gives them the opportunity to replace each other or form blastulae. An increase in cell size entails an increased need for nutrition and, in addition, this means that their lifespan is reduced. All this directly affects the overall rate of red blood cells in the blood and the human condition.

When a large number of red blood cells die, iron is released and there is more bilirubin, which puts an increased burden on the liver, and as a result, it cannot process these substances.

The RDW index is directly related to the pathological process during which the dimensions of red blood cells change (anisocytosis). This condition is a complex chemical process that causes all blood cells to suffer.

How is it calculated?

The RDW indicator is calculated as a percentage, the norm of which is the limit from 11.5 to 14.8. The distribution index of erythrocytes is determined using a mathematical equation, which is the ratio of modified red blood cells and their total mass.

At present, laboratories use computer technology that allows you to calculate the percentage of deviation from the established norm. The results of the calculation are presented in the form of a histogram depicting a curve that indicates the likely changes in the size of red blood cells.

Normal performance

The norms of the erythrocyte distribution index depend on gender, age and the presence of certain conditions that occur in the human body. For children under one year old, the normal rate is 11.5-18.7%. At the age of one and older, the values ​​tend to the generally accepted norm, which is 11.5-14.5%.

For the female half of humanity, the upper limit shifts to 15.5%, because their hormonal levels change too often: during pregnancy, lactation, oral contraceptives, menopause.

For analysis, blood is taken on an empty stomach in the morning (until 9 am). It is very important that before this procedure a person does not take any medications, and also stays in a balanced internal state.

Raise RDW

The level of RDW in some situations is elevated. The most common cause of this pathology is iron deficiency anemia. The indicator can change at different stages of the development of pathology, which clearly reflects the histogram of erythrocytes:

  • The initial stage of the development of anemia is characterized by normal indices, but hemoglobin will be greatly reduced. This is the result of healthy functioning of the spinal cord.
  • The next stage of development in the histogram will show an increase in RDW. When there are problems with hemoglobin, indicators such as the average concentration and content of hemoglobin in the blood cell, the average volume of red cells decrease.

In the treatment of IDA, it is necessary to normalize the level of iron-containing protein concentration and its characteristics in human blood.

What do low scores mean?

Patients often ask what it means: "erythrocyte distribution index is lowered." Since the erythrocyte distribution index cannot be estimated without a volume indicator, it is necessary to familiarize yourself with all options for underestimated indicators with their relationship:

  1. RDW is low, and MCV is below average - indicates the presence of problems with the spleen and liver.
  2. RDW is lowered, and MCV is higher than the normal level - indicates the presence of oncological pathologies, mainly the development of bone marrow metastases.

The fact that the distribution index of erythrocytes RDW sd is reduced, from a biological point of view, cannot, in principle, be observed. For this reason, most often the patient is offered to donate blood again, observing the following conditions:

  • stop smoking and drinking alcohol within 24 hours before blood sampling;
  • before the analysis, do not take any medications;
  • refuse to eat smoked and salty foods the day before.

In the case when the distribution index of erythrocytes RDW sd is really lowered, which is necessarily confirmed by deviations from the norm of the MCV indicator, this indicates the occurrence of certain pathologies. These include:

  • Hypochromic microcytic anemia - sometimes also called anemia. A condition in which irregularly shaped red blood cells die because they have no biological value in the body.
  • Malignant tumors - usually in this case we are talking about mastopathy, bone marrow and lung cancer.
  • Hemolysis of red blood cells is the process during which red blood cells die before reaching their target. As a result, active hemoglobin is released.

The reasons

So, the distribution index of erythrocytes is lowered - what does this mean? There are several reasons that can lower the RDW:

  • Acute blood loss in trauma and pathological bleeding.
  • Frequent operations.
  • A metabolic disorder in which the food consumed is not completely digested.
  • Hormonal failure, which is most common in women.
  • Deficiency in the body of B vitamins and iron.
  • Blood diseases characterized by rapid destructive processes.

What measures to take?

What to do when the erythrocyte distribution index is lowered?

A highly qualified doctor at the consultation will most likely ask the patient to take the test again, because the RDW indicator is almost never underestimated. Since this suggests that all cells are ideal in their parameters, and this, in principle, cannot be. If the indicator is confirmed upon re-analysis, then a complete study of the state of the body is carried out, paying special attention to oncological examinations.

Preventive measures

You can prevent a low RDW by following these simple rules:

  • The diet should be balanced, which includes a lot of fresh fruits, lean meats and vegetables.
  • It is recommended to breathe fresh air as often as possible.
  • An active lifestyle will help prevent the RDW index from dropping.
  • It is very important not to miss scheduled medical examinations, during which serious deviations from the norm are most often detected that do not have external symptoms.

As a result, we learned that the distribution index of erythrocytes reflects their dimensions relative to each other and makes it possible to learn about their biological value. A decrease in the RDW is very rare, but if the distribution index of erythrocytes is low, this means that various pathologies are possible.

The index is calculated based on the results of a general blood test, but it can only be fully valid in conjunction with the MCV indicator, since they are closely interconnected.

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