P24 analysis. Prognostic significance of the detection of HIV P24 antigen when using test systems with increased analytical sensitivity

Antigen to HIV: What does it represent, what role does the diagnosis play?

Immunodeficiency virus diagnosis different ways. However, the highest popularity is recently gaining super-sensitive test suits. With their help, it is possible to identify this ailment in the earliest stages. For this, the HIV antigen is used, the presence of which in the body is guaranteed to indicate an unpleasant and dangerous diagnosis. For its detection, several different studies are applied.

Why is the reaction of HIV 1, 2 antigen antibodies is the most reliable indicator of the presence of an immunodeficiency virus?

Verification for immunodeficiency virus in state medical institutions is free. But it is produced in two stages in the event that it is necessary. Initially, the AG to HIV are not checked. The first analysis for the presence or absence of this disease is aimed at identifying antibodies. This is an IFA testing. An immunoassimensional analysis allows you to identify people who are guaranteed not sick by the immunodeficiency virus (if the test was conducted in all the rules).

As well as conditionally infected. Why conditionally? The fact is that antibodies to HIV 1,2, in contrast to the AG to this virus, are allocated in the body and for other reasons. What exactly is specifically. First of all, this is possible for diseases of the immune system. During problems with this vital system, the body produces antibodies as protection, which are determined by immunoassimize analysis, as well as those that appear with a given dangerous ailment. If the result of the IFA turns out to be positive, the patient is directed to an additional study, which is based on the detection of the AG - AT 1,2 reaction. In the clinics most often used immune blotting. This is the most common type of analysis of the virus detection of the immunodeficiency. With its help, the antigen and antibodies to HIV 1 and 2 are not only detected, but also checked for the strength of the reaction.

What is antigen P24 to HIV?

Before talking about what methods, HIV AG HIV antigen can be detected, it should be explained what it represents. Scientists have long been able to find out that the AH, which is marked in the form of tests and in laboratories to marking P24, is a retrovirus capside. Speaking simple wordsIt is a protein of immunodeficiency virus. The definition of the HIV antigen is impossible without detecting antibodies of the first and second type. After all, AG are firmly connected with antibodies. They are formed in the body as an immune response to the appearance of AT, which, in turn, are a kind of "interventions", aimed at destroying the immune system and producing hazardous biological material.

AT and AG to HIV 1 and 2 types are detected in the reaction with each other. The first is performed in the human body the role of alien molecules. The second serve as peculiar developers of proteins or polysaccharides. In the case of the immunodeficiency virus, the AG cause an immune response. Accordingly, in medicine and science associated with the study of this disease, they are classified as immunogens.

P24 Antigen HIV 1 and 2 types are detected only by means of a comprehensive study of biological material. Most often for analysis use venous blood. In some cases, the sperm or secretory fluid is suitable for this, highlighting the female genitals. Combined analysis by HIV Antigen It is produced in three known methods. What specific studies are we talking about? This is immune blotting, a combo test (HIV Combo HIV) and immunohemial surminescent analysis. Each of them should be spoken separately.

Immune blotting: antibodies and antigens to HIV 1 and 2

As mentioned above, immune blotting is one of the most common tests that detect HIV antigen. How is it produced? Initially, the patient take blood from Vienna. The survey is made on an empty stomach. For thirty - forty minutes before this, the patient is not recommended to smoke. The essence of the study is that if a person in the body has an immunodeficial virus of 1 or 2 of the type, the reaction of the antigen - antibodies is random and inseparable. The biological material of the test first is cleaved in a special reagent, then placed on a strip, as a blister with polystyrene cells. As a result of adding special reagents, a laboratory manner first finds out whether this reaction will occur, and then with repeated blood flushing, makes conclusions about how much it is. This allows you to understand whether the immunodeficiency virus is in the body, which is later the most important factor in diagnosis.

Analysis on HIV AG-AT, produced by immune blotting, is recommended to take no earlier than four to five weeks after the intended infection. Despite the fact that this test is a fourth generation system, it does not apply to supercillable and has an error of a few percent (from two to three).

Super sensitive analysis: HIV DUO HIV (combo) antibodies 1, 2 types

Analysis on HIV (HIV) AG - AB (AG-AT) Combo Unlike immune blotting is super-sensitive. Specialists in the field of medicine argue that its use is advisable in two weeks after the intended infection. It is aimed at studying specific antibodies that are a kind of immune response of the human body on such an intervention as an immunodeficiency virus, as well as AG P24. NIV Duo HIV antibodies 1 and 2 types are also aimed at identifying antibodies to this dangerous fear. With it, it is possible not only to detect them in the blood, but also determine the type of disease.

The test for the HIV COMBO antigen is combined. With it, the antigen antigen reaction is also checked, which indicates the presence of a terrible ailment in the body.

Immunohemiallyuminescent analysis: HIV 1.2 Combo HIV AT-AG MIL

The Illa test on HIV AT-AG is also super-sensitive. This study is based on a peculiar reaction of AG-AT. The specificity of the method is the order of ninety-two percent, while its accuracy is from ninety-eight to ninety nine. From this we can conclude that the error in such an analysis is, but it is relatively small. And if necessary, it is easily overlapped by re-inspection. This analysis is applied after two or three weeks after the alleged infection.

This combo test for HIV is aimed at studying venous blood, in the case of a test for the presence of an immunodeficiency virus in the body. When identifying other diseases and pathologies, urine or secretory fluid is used, which is distinguished from the genitals. AT and AG to immunodeficiency virus during ILYL is also checked for the reaction. This uses special reagents and strippers with cells. The study conducted in several stages allows you to quickly and accurately diagnose or refute it.

All of the above methods for diagnosing the immunodeficiency virus by means of the AT-AG reaction are effective. They differ only at admissible studies of the study. Deciding which specifically the method should be used, should a doctor.

HIV / AIDS analysis - blood antigen

There is no antigen P24 in serum.

Antigen P24 - white nucleotide wall protein. The stage of primary manifestations after the infection of HIV is a consequence of the start of the replicative process. The antigen P24 appears in the blood in 2 weeks after infection and can be detected by the ELISA method from 2 to 8 weeks. After 2 months from the beginning of infection, the antigen P24 disappears from the blood. Later B. clinical flow HIV infections note the second rise in the blood content of protein P24. It falls for the period of AIDS formation.

Existing IFA test systems for detection of antigen P24 are used for early detection of HIV in blood and children's donors, determining the forecast of the course of the disease and control over the therapy. The IFA method has a high analytical sensitivity, which allows to detect the antigen P24 HIV-1 in serum in concentrations of 5-10 Pkg / ml and less than 0.5 ng / ml of HIV-2, and specificity. At the same time, it should be noted that the content of the antigen P24 in the blood is subject to individual variations, which means that only 20-30% of patients can be identified with this study in early period After infection.

Antibodies to antigen R24 classes IGM and IgG in blood appear, starting from the 2nd week, reach a peak for 2-4 weeks and are held at such a level of different times - IGM class antibodies for several months, disappearing within a year after infection, And IgG antibodies can be maintained for years.

Medical Expert Editor

Portnov Alexey Alexandrovich

Education: Kiev National Medical University. A.A. Bogomolets, specialty - "Therapeutic business"

HIV diagnostics methods

Currently, new diagnostic technologies make it possible to identify the etiological and pathogenetic causes of many diseases and radically affect the results of treatment. Perhaps the most impressive results of the introduction of these technologies in clinical practice are achieved in the field of immunology and diagnostics. infectious diseases.

The test systems based on immuno-enamant and immunohemyluminescent analysis make it possible to identify antibodies of various classes, which significantly increases the information content of the methods of clinical, analytical sensitivity and specificity for the diagnosis of infectious diseases. It should be noted that the most significant successes in the diagnosis of infections are related to the implementation of the method of polymerase chain reaction to the laboratory practice, which is considered to be the "gold standard" in the diagnosis and evaluation of the effectiveness of the treatment of a number of infectious diseases.

To study, various biological material can be used: serum, blood plasma, scraping, bioptat, pleural or spinal fluid (SMG). First of all, methods laboratory diagnostics infections are aimed at identifying diseases such as viral hepatitis In, s, d, cytomegalovirus infection, sexually transmitted infections (gonorrheal, chlamydial, mycoplasma, ureaplasmen), tuberculosis, HIV infection, etc.

HIV infection - a disease caused by a human immunodeficiency virus (HIV), for a long time persistent in lymphocytes, macrophages, nervous tissue cells, resulting in slowly progressive damage to immune and nervous systems The body, manifested by secondary infections, tumors, subacute encephalitis and other pathological changes.

Infection pathogens are viruses of the immunodeficiency of the person of the 1st and 2nd types (HIV-1, HIV-2) - refer to the family of retroviruses, the submissions of slow viruses. Virions are spherical particles with a diameter of 100-140 nm. The viral particle has an outer phospholipid shell, including glycoproteins (structural proteins) with a certain molecular weight measured in kilodaltones. HIV-1 is GPL60, GPL20, GP41. The inner sheath of the virus covering the kernel is also represented by proteins with a known molecular weight - P17, P24, P55 (HIV-2 contains GPL40, GPL05, GP36, P16, P25, P55).

The HIV genome includes RNA and reverse transcriptase enzyme (reverse). In order for the retrovirus gene to connect with the genome of the host cell, first with the help of reversal, DNA synthesis on the matrix of viral RNA occurs. Then the DNA of the Provirus is embedded in the host cell genome. HIV has a pronounced antigenic variability, significantly exceeding such an influenza virus.

In the human body, the main target of HIV are T-lymphocytes that carry the largest amount of CD4 receptors on the surface. After penetrating HIV into a cage using a revertase according to its RNA, the virus synthesizes the DNA, which is embedded in the host cell's genetic apparatus (CD4 lymphocytes) and remains there for life in a state of the provirus. In addition to T-lymphocytehelpers, macrophages are affected, in-lymphocytes, cells of neuroglia, intestinal mucosa and some other cells. The reason for reducing the amount of T-lymphocytes (CD4 cells) is not only a direct cytopathic effect of the virus, but also their merging with non-infected cells. Along with the lesion of T-lymphocytes in patients with HIV infection, there is a polyclonal activation of B-lymphocytes with an increase in the synthesis of immunoglobulins of all classes, especially IgG and IgA, and the subsequent depletion of this department of the immune system. The violation of the regulation of immune processes is also manifested by an increase in the level of α-interferon, β2-microglobulin, a decrease in IL-2 level. As a result of the impairment of the function of the immune system, especially with a decrease in the number of t-lymphocytes (CD4) to 400 cells in 1 μl of blood and less, conditions arise for uncontrolled HIV replication with a significant increase in the number of virions in various environments. As a result of the defeat of many links of the immune system, a person infected with HIV becomes defenseless before causative agents of various infections.

Against the background of increasing immunosuppression, severe progressive diseases are developing, which are not found in a person with a normal functioning immune system. These are diseases that the World Health Organization (WHO) identified as AIDS marker or AIDS-indicator diseases.

The first group - diseases inherent only by heavy immunodeficiency (CD4 level<200). Клинический диагноз ставится при отсутствии анти-ВИЧ-антител или ВИЧ-антигенов.

The second group is diseases that can develop both against the background of severe immunodeficiency and in some cases without it.

Therefore, in these cases, laboratory confirmation of the diagnosis is necessary.

• candidiasis of the esophagus, trachea, bronchi;
• extrapole cryptococcosis;
• cryptosporidia with diarrhea more than 1 month;
• cytomegalovirus lesions of various organs besides the liver, spleen or lymph nodes in a patient under the age of 1 month;
• the infection caused by a veil of a simple herpes, manifested with ulcers on the skin and mucous membrane, which personify more than 1 month, as well as bronchitis, pneumonia or esophagitis of any duration, affecting a patient over the age of 1 month;
• generalized sarcoma capos in patients under the age of 60;
• brain lymphoma (primary) in patients under the age of 60;
• lymphocytic interstitial pneumonia and / or pulmonary lymphoid dysplasia in children under the age of 12;
• disseminated infection caused by atypical mycobacteriums (mycobacteria of M. Aviumintracellulare complex) with extrapilence localization or localization (additionally to light) in the skin, cervical lymph nodes, lymph nodes of the lungs;
• pneumatic pneumonia;
• progressive multi-grade leukoentephalopathy;
• toxoplasmosis of the brain in patients over the age of 1 month.

• bacterial infections, combined or recurrent, in children under the age of 13 years (more than two cases for 2 years of observation): sepsis, pneumonia, meningitis, bone or joints, abscesses due to gemophilic sticks, streptococci;
• coccidioidomycosis Disseminated (extrapilence localization);
• HIV-encephalopathy (HIV dementia, AIDS dementia);
• histoplasmosis with diarrhea persistent more than 1 month;
• isosport with diarrhea persistent more than 1 month;
• sarcoma Caposhi at any age;
• brain lymphoma (primary) in persons of any age;
• other B-cell lymphomas (with the exception of Hodgkin's disease) or lymphoma of an unknown immunophenotype: fine-cell lymphoma (such as Lymphoma of Berkitta, etc.); immunoblastic sarcoma (immunoblastic lymphoma, large cell, diffuse histiocyte, diffuse undifferentiated);
• mycobacteriosis is disseminated (not tuberculosis) with a lesion in addition to light skin, cervical or roasting lymph nodes;
• tuberculosis extrapulic (with damage internal organs, in addition to the lungs);
• salmonellic septicemia recurrent;
• HIV-dystrophy (exhaustion, sharp weight loss).

There are many AIDS classifications.

According to the new classification proposed by the Disease Control Center (Table 2 - see the source reference above), the diagnosis of AIDS is established by persons having a CD4-lymphocyte level of less than 200 / μl even in the absence of AIDS indicator diseases.

Category B includes various syndromes, the most important of which are bacillage angiomatosis, orofaring towed candidiasis, recurrent candidial vulvivaginitis, difficult to be therapy, cervical dysplasia, cervical carcinoma, idiopathic thrombocytopenic purple, lesteriosis, peripheral neuropathy.

Antibodies to HIV-1 and HIV-2 in the blood

Antibodies to HIV-1 and HIV-2 in the serum is absent.

The definition of HIV antibodies is the main method of the laboratory diagnosis of HIV infection. The method is based on an enzyme immunoassay analysis (IFA) - sensitivity of more than 99.5%, specificity - more than 99.8%. HIV antibodies appear in 90-95% infected within 1 month after infection, 5-9% after 6 months, in 0.5-1% in later. In the AIDS stage, the number of antibodies may decline until complete disappearance.

The result of the study is expressed qualitatively: positive or negative.

The negative result of the study indicates the absence of antibodies to HIV-1 and HIV-2 in serum. The negative result of the laboratory issues immediately by its readiness. Upon receipt of a positive result - detecting antibodies to HIV - to avoid false-positive results in the laboratory, the analysis is repeated 2 more times.

Immunoblotting for antibodies to virus proteins HIV in serum

Antibodies for viral proteins HIV in serum is absent.

The IFA method to determine the antibodies to HIV is screening. When obtaining a positive result, the immunoblotting method is used to confirm its specificity - counter precipitation in the gel of antibodies in the serum of the patient with various viral proteins, subjected to the molecular weight separation using electrophoresis and nitrocellulose applied. Antibodies for viral proteins GP41, GPL20, GPL60, P24, PI8, P17, etc. are determined.

According to the recommendations of the Russian Center for the Prevention and Control of AIDS, the detection of antibodies to one of glycoproteins GP41, GPL20, GPL60 should be considered a positive result. In case of detection of antibodies to other virus proteins, the result is considered doubtful, such a patient should be examined twice - after 3 and 6 months.

The absence of antibodies to specific HIV proteins means that the immuno-immunimen method gave a false positive result. At the same time, in practical work, in assessing the results of the Immunoblotting method, it is necessary to be guided by the instruction attached by the company to the "set of immunoblotting" used.

Immunoblotting method is used for the laboratory diagnosis of HIV infection.

Antigen P24 in serum

Antigen P24 in the serum is absent.

The antigen P24 is a protein of the HIV nucleotide wall. The stage of primary manifestations after the HIV infection is a consequence of the beginning of the replicative process. Antigen P24 appears in the blood after 2 weeks after infection and can be detected by the ELISA method from 2 to 8 weeks. After 2 months from the moment of infection, the antigen P24 disappears from the blood. In the future, in the clinical course of HIV infection, the second increase in the blood content of protein P24 is noted. It comes from the formation of AIDS. Existing IFA test systems for detection of antigen P24 are used for early detection of HIV in blood donors and children, determining the forecasting of the flow of AIDS and control the therapy in patients with AIDS. ELISA has high analytical sensitivity, which allows to detect HIV-1 antigen R24 in serum in a concentration of 5-10 Pkg / ml and HIV-2 - less than 0.5 ng / ml, and specificity. However, it should be noted that the level of antigen P24 in the blood is subject to individual variations, which means that only 20-30% of patients can be detected using this study in the early period after infection (Rose N.R. et al., 1997).

Antibodies to Antigen R24 Classes IGM and IGG in the blood appear from the 2nd week, reach a peak for 2-4 weeks and held at such a level of different times: IGM class antibodies - for several months, disappearing within one year after infection, And IgG antibodies can be maintained for years.

The algorithm for the diagnosis of HIV infection depends on the phase of the disease and is characterized by a change in the dynamics of detection antibodies of various classes (Fig. 1, 2 - see the source reference above).

The result of the study is expressed qualitatively - positive or negative. The negative result of the study indicates the absence of antibodies to HIV-1 and HIV-2 and the antigen P24 in serum.

The negative result of the laboratory issues immediately by its readiness. Upon receipt of a positive result - detecting antibodies to HIV-1 and HIV-2 and / or antigen P24 - to avoid false positive results in the laboratory, the analysis is repeated 2 more times.

Regardless of the results of the study of the patient's blood sample and the results of 3 studies are sent to the Laboratory to the AIDS Regional Center to confirm a positive result or verification of an indefinite result. In such cases, the final response to this study issues the Regional Center for AIDS.

HIV detection by polymerase chain reaction (qualitatively)

The detection of HIV method of polymerase chain reaction - PCR (qualitatively) is carried out in order to:

• permission of dubious results of immunoblotting research;
• for early diagnosis of HIV infection;
• control of the effectiveness of antiviral treatment;
• definitions of the stage of the AIDS disease (transition infection in the disease).

When primary infection, HIV, the PCR method allows you to identify HIV RNA in the blood after 10-14 days after infection.

The result of the study is expressed qualitatively: positive or negative. The negative result of the study indicates the lack of HIV RNA.

A positive result is the identification of HIV RNA - testifies to the infection of the patient.

HIV detection by polymerase chain reaction (quantitatively)

HIV in the blood is absent.

A direct quantitative determination of HIV RNA with PCR allows more precisely than determining the CD4 cell content, predict the speed of AIDS development in people infected with HIV, therefore, more accurately assess their survival. The high content of viral particles usually correlates with a pronounced impaired immune status and low CD4 cells. The low content of viral particles usually correlates with a more prosperous immune status and a higher content of CD4 cells. The content of viral RNA in the blood allows to predict the transition of the disease into the clinical stage. When maintaining RNA-1 HIV\u003e copies / ml, almost all patients develop clinical picture AIDS (Senior D., Holden E., 1996).

The likelihood of AIDS development is 10.8 times higher in persons with HIV-1 in the blood\u003e copies / ml than those with HIV-1 in the blood<копий/мл. При ВИЧ-инфекции прогноз непосредственно определяется уровнем виремии. Снижение уровня виремии при лечении улучшает прогноз заболевания.

The US expert team has developed indications for therapy of patients with HIV. Treatment is shown to patients with CD4 cells in the blood<300/мкл или уровнем РНК ВИЧ в сыворотке >copies / ml (PCR). Assessment of the results of antiretroviral therapy in individuals infected with HIV are carried out to reduce the level of HIV serum RNA.

With effective treatment, the level of Virhia must decrease 10 times during the first 8 weeks and be below the sensitivity limit (PCR) (<500 копий/мл) через 4–6 месяцев после начала терапии.

Thus, today, many research methods are introduced into clinical practice to diagnose HIV infection, as well as for all other viral infections. Among them, the leading role is assigned to serological studies. The main methods of diagnosing HIV infections are presented in Table 3 (see reference to the source above), where they are divided depending on the importance of each method to detect viruses to four levels:

• A - test is usually used to confirm the diagnosis;
• B - the test is useful in certain circumstances for the diagnosis of individual forms of infection;
• C - Test is rarely used for diagnostic purposes, but is of great importance for epidemiological surveys;
• D - Test is usually not used by laboratories for diagnostic purposes.

Since to diagnose viral infections, in addition to choosing the optimal analysis method, it is equally important to the correct definition and taking of biomaterial for the study, in Table 4 (see reference to the source above) provide recommendations for the choice of optimal biomaterial for HIV study.

To monitor HIV-infected, it is necessary to use the possibilities of a comprehensive study of the immune status - the quantitative and functional definition of all its links: humoral, cellular immunity and nonspecific resistance in general.

In modern laboratory conditions, the multi-stage principle of evaluating immunological status includes the determination of the subpopulation of lymphocytes, blood immunoglobulins. When evaluating indicators, it should be borne in mind that for HIV infection is characterized by a decrease in the ratio of CD4 / CD8 T cells less than 1. The CD4 / CD8 index 1.5-2.5 shows the normergic state, more than 2.5 - indicates hyperactivity, less 1.0 - indicates immunodeficiency. Also, the CD4 / CD8 ratio may be less than 1 with a severe flow of the inflammatory process.

Of principled significance, this ratio has in assessing the immune system in patients with AIDS, because HIV selectively affects and destroys CD4 lymphocytes, as a result of which the CD4 / CD8 ratio is reduced to values, significantly less than 1.

Evaluation of immunological status is also based on the detection of common or "coarse" defects in the system of cellular and humoral immunity: hypergammaglobulinemia (increase in concentration of IGA, IgM, IgG) or hypogammaglobulinemia in the terminal stage; an increase in the concentration of circulating immune complexes; reduced cytokine products; Weakening of the response of lymphocytes on antigens and mitogen.

The violation of the ratio of populations in the general bullet in lymphocytes is characteristic of the insufficiency of humoral immunity. However, these changes are nonspecified for HIV infection and may occur with other diseases. In a comprehensive assessment of a number of other laboratory indicators, it should be borne in mind that for HIV infection is also characteristic of: anemia, lymph and leukopenia, thrombocytopenia, increasing the level of β2-microglobulin and C-reactive protein, increasing the activity of transaminase in serum.

Antigen P24 in serum

Ag p24 in serum is absent.

AG P24 - white nucleotide wall protein. The stage of primary manifestations after the infection of HIV is a consequence of the start of the replicative process. AG P24 appears in the blood in 2 weeks after infection and can be detected by the ELISA method from 2 to 8 weeks. After 2 months from the beginning of infection, AG P24 disappears from the blood. In the future, in the clinical course of HIV infection, the second rise in the blood content of protein P24 is noted. It falls for the period of AIDS formation. Existing IFA test systems for detection AG P24 is used for early detection of HIV in blood donors and children, determining the forecast of the course of the disease and control over the therapy. The IFA method has a high analytical sensitivity, which allows to detect HIV-1 HIV-1 in serum in concentrations of 5-10 Pkg / ml and less than 0.5 ng / ml of HIV-2, and specificity. At the same time, it should be noted that the content of AG P24 in the blood is subject to individual variations, which means that only 20-30% of patients can be identified with this study in the early period after infection.

AT to AG P24 classes IGM and IgG in the blood appear, starting from the 2nd week, reach a peak for 2-4 weeks and are held at such a level of different times - at class IGM for several months, disappearing within a year after infection, A at IgG can be maintained for years.

The appearance of CL classes at various stages of HIV infection are represented in Fig.

Fig. The appearance of CL classes at various stages of HIV infection

Antibodies to HIV 1 and 2 and HIV antigen 1 and 2 (HIV AG / AB Combo)

Antibodies to HIV 1 and 2 and HIV 1 and 2 antigen (HIV AG / AB Combo) - a complete description of the diagnostics, reading to execution, decoding the results.

Antibodies to HIV 1 and 2 and HIV 1 and 2 antigen (HIV AG / AB Combo) - antibodies formed in the body when infected with the human immunodeficiency virus.

Human immunodeficiency virus (HIV) representative of a family of retroviruses, it damages the cells of the immune system. The virus is two types, HIV-1 occurs more often, HIV-2 is mainly in African countries.

HIV is embedded in human cells, virus particles multiply, as a result, the virus antigens appear on the cell surfaces to which the corresponding antibodies are produced. Their blood detection allows you to diagnose HIV infection.

It is possible to identify the antibodies to the human immunodeficiency virus after three to six weeks after the penetration of the virus into the blood. A sharp increase in blood virus is characteristic of the stage of primary manifestations, this period falls on the third sixth week from the moment of infection and is called "seroconverteys". At this time, the infection can be identified laboratory, and it clinically, it is either not manifested in general, or proceeds as a cold illness with an increase in lymph nodes.

After 12 weeks from the moment of infection of the antibodies, almost all sicks are found. At the last stage of the disease, called AIDS, the amount of antibodies decreases.

At what time from the moment of infection, HIV infection will be detected, depends on the test system used in a particular laboratory. Combined test systems of the fourth-generation detect HIV infection in two weeks from the moment the virus falls into the blood. And the test-system of the first generation was detected by HIV only after 6-12 weeks.

When performing a combined analysis, it is possible to identify an antigen P24 HIV, which is a virus capside. It is determined in the blood after 1-4 weeks after infection, even before the increase in the concentration of antibodies in the blood (to the "seroconversion"). Also, with a combined study, antibodies to HIV-1, HIV-2, available for diagnostics in two to eight weeks after infection are found.

P24, and HIV-1 antibodies to HIV-2 are found before seroconversion in the blood. After the seroconversion of the antibodies bind antigen P24, therefore P24 is not detected, and the antibodies to HIV-1 and HIV-2 are detected. Then in the blood again detected P24, and antibodies to HIV-1, to HIV-2. When the HIV-infected AIDS develops, the production of antibodies is broken, therefore antibodies to HIV-1 and HIV-2 may be absent.

The diagnosis of HIV infection is carried out at the pregnancy planning stage and at the current observation of a pregnant woman, since HIV infection can be transmitted from a woman to the fetus during pregnancy, in childbirth and in breastfeeding.

Indications for HIV diagnostics

Random sex contacts.

Fever without objective reasons.

An increase in lymph nodes in several anatomical areas.

Preparation for research

HIV study is carried out in 3-4 weeks from the time of the alleged infection. If the result is negative, the analysis is repeated after three and six months.

From the last eating before taking the blood of the time interval should be more than eight hours.

On the eve of excluding fatty foods from the diet, do not take alcoholic beverages.

For 1 hour before taking blood, it is impossible to smoke.

Blood for research is passed in the morning on an empty stomach, even tea or coffee is eliminated.

It is permissible to drink ordinary water.

Material for research

Decoding HIV Results Diagnostics

Analysis is high quality. If the antibodies to HIV are not detected, the answer is indicated "negatively".

If the antibodies to HIV are detected, the analysis is repeated on another series of tests. Re-positive result requires a study by the Immunoblot method, the "Gold Standard" of HIV diagnostics.

1. Man is not infected with HIV.
2. The terminal stage of HIV infection (AIDS).
3. Seronegative version of HIV infection (later the formation of antibodies to HIV).

1. Man infected HIV.
2. The test is not informative in children up to one and a half years born from HIV-infected mothers.
3. Flame positive result If there is antibodies in the blood of Epstein-Barr virus, the main complex of histocompatibility, rheumatoid factor.

Select the symptoms who are worrying you, answer questions. Find out how serious your problem is and whether to see the doctor.

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