How to take blood for pcr dna hiv. PCR tests for HIV: reliability and features of the procedure. How many HIV tests are done

One of the most serious diseases that has not yet been cured is caused by the human immunodeficiency virus.

It is not easy to detect a pathogen in the body: at present, only a few research methods are used for this.

One of these tests is polymerase chain reaction (PCR).

To understand the court of the polymerase chain reaction method, you need to remember the peculiarity of the structure of cells from the school course.

Any living cell contains protein and two types of nucleic acids: DNA and RNA. They are the most important cellular structures because they contain genetic information encoded in a special way.

The DNA code is a strict sequence of microstructures that form a long chain.

Reference! The ability of a nucleic acid to reproduce itself is used as the basis for PCR.

When the virus enters healthy cells, it destroys DNA strands.

In this case, the cell will no longer contain complete chains, but only small fragments - nucleotides. In addition, even the smallest particles of the virus will be visible.

It is on the detection of damaged DNA chains and residual cells that the polymerase chain reaction method is built.

There are two types of PCR diagnostics:

• quality. Suitable for those whose diagnosis is not confirmed: it simply shows whether the virus is present in the cells.
• quantitative. The patient receives the result "DNA of the virus is not detected", which means the absence of HIV, or information about the presence of the pathogen, which means that the person is HIV-infected.

If there is a confirmed diagnosis, a quantitative analysis is assigned. With its help, the number of copies of RNA (DNA) of the virus in the blood (cells) is determined. Quantitative analysis makes it possible to assess the effectiveness of treatment in HIV-infected people, to determine the severity of the disease, its progression.

What diagnostic methods can detect HIV infection is described in the video:

Advantages and disadvantages of this diagnostic method

Like any diagnostic measure, PCR has its pros and cons.

The advantages of the method include:

• High reliability. With PCR, it is possible to detect the smallest remnants of the virus, the probability of detecting the pathogen reaches 80% 4-5 days after infection, 100% - 14 days after infection. Thus, the greatest accuracy is achieved when studying the DNA of a virus in blood cells: a virus can be detected when its number is 1-5 copies per 1 million cells.
• Possibility to use various biomaterials(Saliva, urine, sweat and tears are not suitable for PCR, but blood, semen and genital secretions from women can be used).
• Possibility of carrying out the analysis on different diseases on one sample. Using PCR, you can detect HIV, chlamydia, herpes, cytomegalovirus, ureaplasma, mycoplasma, gonorrhea, trichomoniasis, toxoplasmosis.
• Fast speed of getting results. There is an express PCR examination that allows you to find out the diagnostic results in a few hours.
• High sensitivity: PCR, unlike, for example, ELISA, helps to detect the virus already in the first weeks after infection.
• Possibility of obtaining results within a few days after infection. When infected, the virus can be determined after 5-14 days, while ELISA is advisable to carry out only after 6 weeks.
• No age restrictions. PCR can be performed in both adults and children from the moment of birth.

The main feature of PCR analysis is that it does not detect antibodies to the virus, but the virus itself.

There are only a few disadvantages against the advantages:

• High cost.
• The probability of obtaining false positive results is about 20%. Usually this happens due to the fault of the personnel (errors in the collection or transportation of the biomaterial, in the study of the biomaterial and interpretation of the results).
• The need to use advanced high-tech equipment, which only some clinics are equipped with.

Attention! Obviously, the advantages of the technique are much greater than the disadvantages. It is especially important that with the help of PCR it is possible to detect the disease at the initial stage of development and start treatment on time.

The result of the PCR analysis can be positive already 14-21 days after a possible infection. But if the analysis is negative, this does not guarantee the absence of infection. It is better to conduct a confirmatory test with ELISA honey after 2 weeks.

How the PCR test for HIV is carried out is described in the video:

Who is assigned?

First of all, PCR is prescribed for suspected HIV. The technique can also be indicative for the detection of sexually transmitted diseases, hereditary diseases.

Reference! PCR diagnostics are often initiated by a person who has not shown symptoms of the disease, but there is speculation and concern about possible infection, for example, after unprotected intercourse, a recent blood transfusion, contact with an infected person.

Who else is shown the examination?

• People who have tested positive for ELISA twice. PCR will allow you to establish the final diagnosis.
• Donors planning to donate blood.
• People in whom immunoblotting confirmed the diagnosis. Immune blotting is a method for diagnosing AIDS and is usually performed in conjunction with PCR.
• People who are at the stage of treatment of diseases caused by HIV. PCR allows you to evaluate the effectiveness of therapy.
• Newborns whose mother is HIV-positive (transmission of the virus occurs in about 30% of cases). Already 2-3 weeks after birth, it is possible to determine whether an infection has occurred.

Some people are screened as a preventive measure, but this is rare because the cost of PCR testing is high.

How long does the analysis take and where can I take it?

PCR analysis for HIV is carried out in the laboratory.

The blood sampling itself takes 5-10 minutes, and the results are ready the next day.

When choosing express diagnostics (for example, in the laboratories "Invitro" or "Hemotest"), the interpretation of the results by a specialist takes only 2 hours.

In private clinics, diagnostics, if desired, can be done anonymously. To do this, you need to report this during a personal visit: each patient is assigned a serial number and given access to a personal account. Then a person can find out the results even without a second visit to the laboratory.

The reliability of the results of the PCR study is described in the video:

Research cost

PCR diagnostics are not cheap, since they require certain advanced equipment, as well as special specialist knowledge.

The equipment is available only in some medical laboratories, which allows you to set a high cost of analysis.

The average price of a study is 3000-5000 rubles. In some regions, the cost does not exceed 1500-2000 rubles.

Since there is a possibility of false positive and false negative results, or the person applied too early (the virus has not yet broken the DNA structure, but is already present in the body), a second test may be required.

The high cost is also due to the fact that a number of components are required for diagnostics:

1. DNA segment (matrix) intended for amplification;
2. two primers;
3. Polymerase - a chemically active component that accelerates the increase in the number of viral particles exponentially;
4. Deoxyribonucleoside triphosphates;
5. Charged particles of divalent magnesium;
6. A special solution in which the polymerization process is carried out. This solution is designed to maintain a suitable level of acidity, salt concentration, amount of magnesium in the liquid.

Also, the study requires a small amount of petroleum jelly: it contains fats and boils at a high temperature, which protects the studied sample from overheating.

Conducting an analysis

Blood, semen and vaginal discharge are suitable for analysis. Usually, often use venous blood.

Blood sampling is performed in the morning on an empty stomach.

In addition, you need to prepare for the analysis:

• 2-3 days before the diagnosis, fatty foods should be excluded from the diet.
• Alcohol is excluded 1-2 days before the analysis.
• 2 weeks before the analysis, you need to stop taking immunostimulating drugs.
• The last meal should occur no later than 8 hours before blood donation.

When taking blood from a vein, the inner bend of the elbow is treated with a special solution, after which the specialist pierces the skin, places the needle of the vein syringe and takes the right amount of blood. Then the needle is removed, the place is again treated with alcohol, the patient is given a cotton swab.

The patient must temporarily bend the arm to stop the bleeding. If a person feels well, he can immediately go home. With dizziness, nausea and fainting, he is given first aid.

The laboratory assistant places the obtained biomaterial in a sterile flask and sends it for diagnostics. The specialist mixes the split biological material in a special reactor with enzymes that synthesize various infections.

If there are very few virus particles in the blood, their number increases sharply when interacting with enzymes: the reagents combine with the DNA of the virus and duplicate it.

The analysis is carried out in several stages, since the division of molecules occurs exponentially. From one cell it turns out 2, from 2 - 4 and so on.

Analyzing the opinions and reviews of doctors, we can say with confidence: at present, PCR diagnostics is the most accurate method for testing for HIV infection.

Reference! Using the analysis, it is possible to establish the presence of the virus in the body within a few days after infection, even if the number of viral structures is only 1-5 units per million cells. However, do not forget about the shortcomings of the method, for example, the likelihood of obtaining false positive results.

Nevertheless, PCR remains one of the few tests that allow you to diagnose the disease in time and start treatment.

The PCR diagnostic technique was originally developed 35 years ago by the American scientist Kari Mullis. The inventor of the study received an international Nobel Prize in 1993 for his pioneering work. It has become indispensable for any laboratory activity.

PCR is used in molecular biology to make many copies (amplify) of small sections of DNA. DNA polymerase can only add a nucleotide to a pre-existing 3-OH group. So he needs a primer to which he can add the first nucleotide. This requirement allows you to define a specific section of the pattern sequence that needs to be diagnosed. At the end of the PCR reaction, a particular sequence will accumulate in billions of copies (amplicons).

PCR involves a heating and cooling process called thermal cycling, which is performed by specialized machinery. The polymerase chain reaction (PCR) is a relatively simple technique. It amplifies the DNA template to obtain specific DNA fragments in vitro (in vitro analysis). Traditional methods of cloning a DNA sequence in a vector and replicating it in a living cell often require research from several days to several weeks of work. But you can get the results of amplification of DNA sequences using PCR after a couple of hours.

Most of the biochemical analyzes used in the diagnosis of infectious diseases require a fairly large amount of biological material. For PCR, this condition is not mandatory. Thus, PCR can provide more sensitive pathogen detection. And higher levels of amplification of certain sequences in less time with a fairly limited amount of biomaterial. These features make the technique extremely useful. Not only in fundamental research, but also for personal purposes. Including genetic identity testing, forensics, industrial quality control.

The main value of the analysis lies in the possibility of detecting sexually transmitted pathologies before the first signs develop. PCR analysis is used if early diagnosis of HIV infection is necessary. As well as determining the RNA of the virus in the blood of a donor. Due to the high sensitivity of the assay, a response can be obtained 7-14 days after the alleged infection. The reliability of diagnosis will reach from 85 to 98%. However, the PCR test is not assigned to everyone. Because it is quite expensive research. Most importantly, it requires expensive equipment and certain professional skills from laboratory staff. If the patient has not previously been in situations associated with an increased risk of infection, a polymerase reaction is not advisable.

Qualitative type polymerase reaction for HIV

Conducting high-quality PCR for HIV allows you to determine the presence of a viral disease in the body. The patient can get the result in the form of the following marks: positive, false positive, negative. But the study does not make it possible to determine the number of copies of the retrovirus. Qualitative analysis is not performed in patients who have previously been diagnosed with infection. It is not prescribed as a control over the effectiveness of antiviral therapy.

PCR quantitative type for HIV

It is carried out in order to determine copies of the virus RNA in the biological material of the patient. Quantitative PCR is prescribed only for patients with a previously identified infection, as a monitoring of ongoing treatment.

real time PCR

It is used in laboratory diagnostics for the formation of copies of DNA sections. Also for the simultaneous quantitative study and detection of the DNA sequence in the biomaterial. In fact, the diagnosis is a quantitative PCR.

On a note!

In various laboratories, you can find several diagnostic formulations: “PCR quantitative determination” and “Real-time PCR”.

Both analyzes are identical.

Taking material for HIV diagnosis

The sampling of biological material for the diagnosis of HIV using PCR is carried out according to certain standards. Manipulation is carried out in the treatment room. Disposable sterile instruments are used. The opening of the package with instruments is carried out directly near the patient. The collected material is placed in sterile tubes pre-treated with CrO3 (chromium mixture). The biological material is venous blood, which is donated in the morning and on an empty stomach. A few days before the test, you should exclude the use of alcohol, fatty and spicy foods, stop taking medications.

If it is not possible to withdraw the medicinal products, this should be reported prior to the analysis.

Additionally, a swab from the urethra and vagina can be taken to identify concomitant sexually transmitted diseases. The study is conducted anonymously, the patient receives the results personally. It is recommended to have an ID with you.

How long can I take PCR for HIV

It is possible to detect the presence of the HIV virus later 4-6 days after infection. In this case, the information content of the analysis will reach 85%. After 10-13 days, the analysis can determine the disease with an accuracy of 98%. A negative result will be valid only if it is submitted no earlier than 2 weeks after the alleged infection.

Reasons for a false positive result

It is difficult to get a false positive result.

This is possible in case of non-compliance with the rules for sampling biological material, incorrect labeling of the tube, the use of a low-quality test system, and other similar factors. In other cases, the chance of obtaining such a result is no more than 2%.

How long does it take to get test results?

From a technical point of view, PCR results can be obtained within 4 hours. However, in practice, the patient receives a laboratory conclusion from one to several days. In general, the timing depends on the workload of the laboratory and on how organized its work is.

Carrying out a polymerase reaction in a newborn

PCR is prescribed when a child is born from an HIV-positive mother. Conducting ELISA in this case is not informative. Since the child has antibodies against the retrovirus until about 2 years of age. For this reason, enzyme immunoassay will not give an accurate answer. When conducting PCR in a child aged 4-6 weeks and receiving a positive result, we will talk about infection.

If PCR performed at the age of 8 weeks to six months shows negative results (provided that the child did not feed on mother's breast milk), infection is excluded.

Why is ELISA better for determining HIV?

The polymerase reaction allows you to identify the RNA of the virus, its presence in the body, including quantitative. The task of ELISA is to determine antibodies to HIV infection. Enzyme immunoassay for determining possible infection is not inferior to PCR, its accuracy reaches 99%. However, unlike PCR, it is not able to determine the disease in the early stages of its development.

Benefits of PCR for HIV

• The polymerase reaction directly determines the presence of an infectious agent. For example, ELISA can only detect antibodies and waste products of a microorganism.
• The assay clearly identifies a particular pathogen, even if there are several cross-reacting ones.
• The technique allows to study any kind of biological material, including dried drops of blood.

Among the shortcomings of PCR, one can single out the increased sensitivity of the analysis. This sometimes causes a false positive result. This happens when even a small amount of foreign DNA is present in the test tube or on the instruments.

Diagnosis of HIV using PCR and ELISA: interpretation, reliability of results

ELISA, in which the test results indicate the absence of antibodies to HIV and the p24 antigen in the body, is negative. If these molecules are present, a positive diagnostic conclusion is issued. In some cases, the patient may receive a false positive or false negative result. This is a consequence of early pregnancy, the presence of a herpes infection, incorrect sampling of material, and violations of the transportation of test tubes. In addition, similar results are found in patients with ongoing autoimmune diseases and hepatitis of various types. A Western Blot (immune blotting) can be performed, which combines ELISA and separation of virus proteins.

Then a positive result will be in the presence of the glycoprotein of the viral infection gp160. It is the precursor of the HIV envelope glycoproteins gp41 and gp120. If these molecules are absent, the conclusion of the laboratory test is considered negative. Conducting Western Blot in combination with ELISA allows you to get results whose reliability exceeds 98%. In the case when the ELISA is positive and the Western Blot is negative, the testing is considered doubtful and requires PCR.

For most women and men, this sexually transmitted disease is the most feared. For this reason, after an accidental intimate relationship without barrier contraception, as well as with a frequent change of sexual partners and after surgical operations, a reasonable person experiences a certain alertness. The most reliable way to clarify is to go to the clinic and take a PCR test for HIV.

The blood test can be used to determine the following indicators:

• Denial / confirmation of the presence of HIV in the latent period (in the first weeks after infection, antibodies are not detected in ELISA tests due to their absence or too low concentration).
• Determination of the genotype of HIV-1, HIV-2.
• Identification of the status in children who were born to mothers-carriers (antibodies to HIV are detected for a long time in all children born to HIV-infected women. It is desirable to determine the DNA of the virus in children under the age of 48 hours of life, 1-2 months, 3- 6 months).
• False-negative, false-positive and doubtful results of ELISA tests.
• Diagnosis of the amount of HIV and monitoring of changes in viral load in dynamics (in the case of an already established diagnosis of AIDS, PCR analysis is used for prognosis, dynamic monitoring and monitoring of ongoing therapy).

Price of PCR test for HIV

PCR ANALYSIS FOR HIV - WHEN IT IS DONE, WHY AND IN WHAT TIME

1. HIV DNA. Human Immunodeficiency Virus (HIV) DNA diagnostics can be used to detect early possible infection after a high-risk event (blood tests are taken as early as 10 days after potential infection). However, in order to completely exclude infection, it is necessary to subsequently conduct a second study and ELISA diagnostics at 4 and 12 weeks.
   Analysis results: HIV DNA (qualitative analysis)- "not found" or "found". In the latter case, repeated additional studies are required to confirm HIV infection. If the result is negative, but there is a high risk of infection, a second examination is required - blood donation by PCR or ELISA after a while.
2. HIV RNA. The quantitative determination of HIV RNA by PCR (the so-called "viral load") is one of the indicators for assessing the prognosis of the course of HIV infection and the earliest indicator of the effectiveness of antiviral therapy. The test is indicated for monitoring the course of the disease, deciding whether to start therapy, and evaluating its effectiveness.
   The study of HIV RNA by PCR can be used in adults with early reliable diagnosis of possible infection after a high-risk episode (approximately 7-10 days after probable infection). The presence of a high titer of HIV RNA in the absence of antibodies allows the diagnosis of acute HIV infection. However, to clarify the diagnosis, it is necessary to conduct a repeated study and ELISA diagnostics within 1 and 3 months.
   The delivery of PCR HIV RNA in pregnant women with this infection 3-4 weeks before the expected date of birth is indicated to resolve the issue of the method of delivery (through the natural birth canal or by caesarean section).
   Analysis results: HIV type 1 HIV RNA (quantitative analysis)- "not detected" (this is normal).
3. HIV resistance. An analysis to determine the resistance of HIV to protease and reverse transcriptase inhibitors is indicated for HIV-infected patients with ineffective therapy, as well as during an acute infection before starting antiviral treatment. The study allows you to determine the resistance of HIV to drugs. Based on the results of the analysis, the infectious disease specialist learns about the presence of resistance mutations to protease inhibitors, nucleoside and non-nucleoside reverse transcriptase inhibitors, as well as information on each amino acid position associated with a drug resistance mutation.
4. Multiprime comprehensive diagnostics: qualitative determination of hepatitis C virus RNA / hepatitis B virus DNA / human immunodeficiency virus (HIV) type 1 and 2 RNA (ultrasensitive method). The analysis allows diagnosing HIV infection, viral hepatitis C and B at an early stage. The study is indicated for the early detection of viral hepatitis B and C, HIV type 1/2 in individuals at risk. Detection of DNA or RNA viruses indicates infection.

Terms of readiness of these blood tests - from 3 to 7 calendar days. You can pass a qualitative and quantitative PCR analysis for the diagnosis of HIV infection in Moscow at our medical center. Blood sampling daily, from 10-00, including

PCR for HIV is one of the most informative methods of molecular genetic diagnosis. This method helps to identify the patient's various infectious diseases and diseases that are inherited. The same diagnostic method is applicable in the case of checking the biomaterial for the presence of HIV, a serious disease that develops throughout the patient's life. With medical assistance, PCR has become one of the recommended tests carried out on a fee basis for suspected human immunodeficiency virus. However, the reliability of the study justifies itself only in 80 out of 100 cases.

PCR diagnostics for HIV stands for polymerase chain reaction. Various types of biological materials are used to study this species. Among them, blood, in addition, secretion from the patient's vagina or seminal fluid in men can be used.

Attention! Saliva for PCR is not used in the diagnosis of HIV. Such an approach is recognized as ineffective, since antibodies to HIV are in the minimum concentration in this material. The same applies to urine, sweat and tears.

The indication for the described study is a double positive ELISA (enzymatic immunoassay). Alternative destinations will be discussed later.

More about the essence of the analysis

The basis of the analysis for HIV by PCR is the ability of the nucleic acid to reproduce itself. Living cells consist of protein and these same acids, in other words, of RNA and DNA. Molecules act as the guardians of the genetic code.
At a low concentration of viral particles (HIV) in the biomaterial, the sample does not include whole DNA (deoxyribonucleic acid) chains, but only their components, called nucleotides. The analysis allows to detect even insignificant remnants of virus cells. It is this fact that explains the ability of PCR to demonstrate results in the early stages - a few weeks after HIV infection.

The most qualitative results from the polymerase chain reaction should be expected in the study of venous blood. The sample is digested with the equipment. The fractions are then subjected to enzymatic treatment. Reactive substances, combined with particles of viral DNA, duplicate it. The number of such elements increases according to the chain principle until their presence (not antibodies) in the patient's blood becomes noticeable to laboratory assistants. None of the existing diagnostic methods work on exactly the same principle.

Reaction components

Using the PCR method, you can find out in advance about the development of the virus in the body. Why can't it be called popular in the field of free medicine and done everywhere? The fact is that such an HIV test is very expensive and requires the following components:

• a matrix of deoxyribonucleic acid, including a segment of DNA intended for amplification;
• two primers (for each chain segment);
• chemically active component polymerase to accelerate the polymerization of viral particles;
• deoxyribonucleoside triphosphates;
• particles of divalent magnesium (charged);
• a special solution for creating favorable conditions, providing the proper level of acidity, salt concentration, the number of magnesium particles in the liquid.

Attention! To protect the sample from overheating, a small amount of petroleum jelly is added to the material, which contains fats and, accordingly, a high boiling point.

The relatively high rate of accuracy of the analysis is due to its increased sensitivity, which stimulates the reaction to antibodies to other viruses.

Advantages and disadvantages of the PCR technique for HIV

For an objective assessment of the method in the table below, we present a number of advantages and disadvantages of the study:

Obviously, the advantages of the technique are greater. If we evaluate the type of diagnosis in terms of the productivity of further treatment and the possibility of extending the patient's life, PCR is the surest way to success.

Analysis Features

The main feature of the described analysis is its ability to diagnose HIV early, which other research methods are not capable of. How many days after the alleged infection can I donate blood for PCR? Usually this time period is 10-14 days. Within the next 24 hours, the patient receives the result. Possible deviations in terms are explained by the individual working conditions of diagnostic centers and clinics.

Purpose of the study

PCR is mostly carried out in order to detect HIV (human immunodeficiency syndrome). However, the analysis can also be taken if you suspect the development of diseases that are sexually transmitted. The same method is applicable in the case of the diagnosis of hereditary diseases.

PDR diagnostics: reasons for conducting

When should I donate blood for PCR? In most cases, biological material is donated when the human immunodeficiency virus has adapted to the conditions of the body, stimulated the production of antibodies and caused the first symptoms of HIV. However, this is justified only if a sufficient amount of time has elapsed after infection and involves an ELISA.

The need for PCR arises at the initiative of the patient who wants to promptly diagnose the disease (if any). The reason for this may be: unprotected intercourse, contact with the biological material of an infected person, a recent blood transfusion, etc.

Who is assigned to PCR?

Determination of HIV infection by PCR on the recommendation of a specialist is carried out in the following cases:

• preliminary diagnosis. PCR accurately confirms or refutes the ELISA result;
• Western blotting confirmed the diagnosis. Immunoblotting is an additional way to study AIDS . Both methods are used together, which eliminates the possibility of making an erroneous diagnosis;
• with confirmed HIV status using PCR, the effect of the selected treatment is monitored;
• for donor blood testing for the presence of HIV antibodies;
• to determine the HIV status of a newborn when the mother is positive. PCR in the first days of life allows you to determine intrauterine infection or infection of the infant during passage through the birth canal. The test is carried out at 2 - 3 weeks after birth.

How long does a PCR analysis take, and where can it be taken?

PCR analysis for HIV is carried out in a special laboratory. The test itself and the interpretation of the result does not require much time: a month or even a week. It takes up to 6 minutes to draw blood. In the usual case, a specialist will need no more than a day to make a diagnosis and issue a conclusion. The first 8 hours are the study of blood, the remaining time is spent on registration. The result can be picked up the very next day after taking the sample. The duration of express testing is 2 hours.

Attention! The compulsory medical insurance policy makes it possible to pass the test free of charge at a public health institution.

Almost any commercial laboratory is able to conduct research, and on an anonymous basis. A person is assigned a special number, to which the results are then tied. This information is uploaded to the institution's website in the user's personal account.

How much does it cost to take a PCR test?

This method of conducting research is quite expensive. This is due to the fact that it is necessary to carry out PCR on the latest medical device, manipulation requires sufficient knowledge from specialists.

An urgent question: how much does it cost for a person to take a PCR test for HIV? This will require around 56-60 dollars.

Conducting an analysis

Conducting a PCR test for HIV involves:

• blood sampling for research;
• additional sampling of sperm from a man and genital secretions from a woman.

Attention! As a result, the test allows doctors to determine a high viral load in order to monitor the patient's condition.

Other features of this HIV test to consider:

• a couple of days before the test, the patient should reduce the amount of fatty foods in the diet;
• blood sampling is performed on an empty stomach;
• enzymes synthesizing various infections are added to the split biological materials in a special reactor;
• the analysis is carried out in several stages, since the division of molecules occurs in an arithmetic progression. A special program compares a large number of cell structures for the detection of HIV.

Accurate diagnostic methods, which include PCR, are expensive, but can detect HIV early. In the treatment of such pathologies, the most important thing is a correct and timely diagnosis, which can improve the quality of human life and its duration.

One of the most accurate and reliable methods of molecular genetic diagnostics is considered to be PCR, that is, polymerase chain reaction. This method allows diagnosing various types of diseases of a hereditary and infectious nature in a patient.

PCR - a study allows you to diagnose one of such complex diseases as, which is difficult to treat. The reliability of PCR for HIV justifies itself only in 80 cases out of 100.

The main way to diagnose HIV infection in the human body is considered to be his blood, that is, testing for this disease is carried out. The simplest and most common way to diagnose is to take venous blood and conduct it in a special laboratory. Of course, the positive result obtained may be false, therefore, it is rechecked in a more accurate research way in the reference laboratory.

Polymerase chain reaction is considered to be a rather expensive procedure, and its implementation requires special equipment and highly qualified specialists. It is for this reason that it has not received wide distribution among the population.

The use of PCR analysis for the diagnosis of HIV allows you to get an accurate and reliable result about the presence of the disease, however, this often depends on the preparation of the patient himself.

PCR analysis is carried out in the following cases:

1. Diagnosis of HIV infection in newborn children who were born from an AIDS-infected mother.
2. To control the concentration of HIV in the patient's blood
3. Donor blood testing.

Even if the PCR test shows a positive result, then the diagnosis is not made only by such a test. Most often it is used as an additional method for resolving disputes.

PCR analysis, unfortunately, cannot be called a universal method, which provides accurate results for the presence or absence of infection in the human body. This is due to the fact that this type of study more often than other methods gives false positive results. This diagnostic method is used when diagnosing a disease or when conducting an HIV infection. It is mainly used as an auxiliary method for diagnosing the AIDS virus.

However, despite the possibility of a false positive result, such an HIV test has a number of advantages over other diagnostic methods. PCR analysis can be carried out as early as 11-15 days after the date of the alleged infection, and all other methods make it possible to assess the presence of the AIDS virus in the human body only after a long period of time. This discrepancy is explained by the fact that most screening tests for HIV are based on the determination of the virus, the formation of which occurs within three months.

The main difference between a PCR study and other diagnostic methods is the fact that it does not detect a virus, but the presence of the virus itself in the patient's body.

It is for this reason that the polymer chain reaction method can be called ideal if there is a need for early detection. In addition, it is possible to resort to carrying out such a method in the case when the presence of antibodies cannot be a reliable indicator.

Learn more about HIV research in the video.

If it is necessary to identify the degree or severity of pathology in the human body, they resort to conducting a PCR study in a quantitative way. It is he who allows you to get information about the level of concentration of infection in the patient's body. The progression of the disease is accompanied by a gradual increase in the concentration of the virus and quantitative PCR diagnostics allows you to determine the stage of infection and the effectiveness of the ongoing. Diagnosing the "viral load" before the diagnosis of the disease and after the treatment allows you to make a conclusion about how effective the treatment is.

Other HIV diagnostic methods

To date, the diagnosis of HIV infection is a standard procedure that involves the use of various types of diagnostics:

ELISA test systems

Such a screening test can detect the virus within a few weeks after it enters the human body. Such a study is not aimed at determining the presence of a virus in a patient, but at diagnosing the production of antibodies to it. There are several generations of ELISA tests, each of which has a different sensitivity. Such a test sometimes gives results, which is explained by improper processing and the presence of various types of pathologies in the patient's body.

immune blotting

In the event that immune blotting shows a positive result, then we can talk about making a final diagnosis of HIV. The main method of its implementation is the use of a nirocellulose strip, on which proteins of viral origin are applied.

Express Methods

This is considered a novelty in the field of diagnosing HIV infection and the result can be assessed within a few minutes after they are carried out. The most accurate and reliable results are given by immunochromatographic tests, the use of which is based on the principle of capillary current.

It is possible to talk about the presence of HIV infection in the body only after confirming the ELISA tests with an IB analysis.

Diagnosis of HIV infection in the human body makes significant changes in his habitual lifestyle and relationships with others. It is the responsibility of the medical staff to keep the results of the tests, and only the patient decides to whom to report his illness. PCR is one of the diagnostic methods that can detect the presence of a virus in the human body in just a few weeks.