Diagnosis of HIV infection. Antigen R24 What is P24 Analysis
Relevance of detection HIV-infected persons In the early stages of infection, it is determined by the need to conduct a more efficient epidemiological examination, timely organization of the necessary preventive events Among contact persons as well possible application The short cycle of antiretroviral therapy in order to reduce the viral load to improve the forecast of the disease. Timely informing a patient about infections contributes to a decrease in risk in the transfer of the disease and its possible participation in donation.
The diagnosis of HIV infection to the appearance of a positive result of the immune blot (IB) is confirmed when the patient's antigen P24 or (and nucleic acid nucleic acid is detected in the serum.
Determination of the antigen P24 with an enzyme immunoassay (ELISA) is a simple and economical way to demonstrate the presence of a viral protein in the patient's blood due to the intensive replication of the virus in the first weeks after infection. The test for antigen P24 is available to laboratories with customary features for ELISA. Compared to the determination of the viral load by the polymerase chain reaction, it is less costly and time consuming. Despite the fact that the strategy for defining infection in the seronegative period is known, so far this test is not included in the HIV diagnosis algorithm. It is known that the greatest percentage of identification of P24 is observed in serums with a dubious result of IB. However, it was shown that test systems with a standard analytical threshold of sensitivity (10 pg / ml) have insufficient diagnostic sensitivity and prognostic significance of the revealed P24 to include into the routine diagnostic process. In this regard, the development and implementation of the test system to antigen P24 with increased analytical sensitivity is of great interest.
The goal of the work is to assess the prognostic significance of the detection of the antigen P24 HIV when using test systems with a different threshold of analytical sensitivity in individuals with a dubious result of IB.
With a retrospective examination of serums with an indefinite result on HIV antibodies in IB, the use of a test system on antigen P24 with a threshold of an analytic sensitivity of 0.5 pg / ml revealed 50% of infected patients, and the use of a test system that detects 8 pg / ml - 22.9%. The use of an additional set of reagents for the destruction of the immune complex allows you to increase the detection of the antigen R24 to 55.3%. The prognostic significance of the presence of HIV infection with additional testing on the antigen P24 was 91.7-96%. Introduction to the diagnostic HIV algorithm for an additional test for antigen P24 HIV with an analytic sensitivity of 0.5 pg / ml allows you to confirm the diagnosis of HIV on early stage Diseases of at least 13% of cases in persons with an uncertain IB result. (See Article: Nehumumaev D.A. et al. "Prognostic significance of the detection of HIV P24 antigen when using test systems with increased analytical sensitivity").
"Wedge. Lab. Diagnosis", 2009, № 2, p. 40 - 42.
Clinical and laboratory diagnosis of HIV infection It has three directions:
- Establishing the fact infected with HIV, diagnosis of HIV infection.
- Definition of the stage clinical flow Diseases and detection of secondary diseases.
- Forecast of the progression of clinical course of the disease, laboratory control of the effectiveness of the treatment and side effects of antiretroviral drugs.
1. Establishment of the infection of HIV, diagnosis of HIV infection
The following specific indicators are used to determine the HIV infection: antibodies to HIV, HIV antigens, HIV RNA and DNA providers. The antibodies to HIV are determined by the method of immunoassay analysis (ELISA) or immunoblotting, which is essentially a type of ELISA. Antigens (proteins) HIV are determined by the IFA method. With the help of molecular genetic methods of the polymerase chain reaction (PNRR) and BDNA, the RNA of HIV and DNA of the Provirus can be determined. The use of additional methods for hybridization of nucleic acids with specific DNA probes allows to test the specificity of DNA sequences obtained during PCR. The sensitivity of PCR is the detection of viral genes in one of five thousand cells.
In the primary infection, the following dynamics of HIV markers in the blood infected are observed. In the first month, as a result of the activation of the replicative process, a sharp increase in the viral load occurs (HIV RNA content in plasma), then due to the dissemination of the virus and mass infection of target cells in the blood and lymphatic nodes, it becomes possible to determine the proviral DNA. A primary diagnostic value is the fact of detecting a provisional DNA integrated into the target cell genome.
The viral load reflects the intensity of the replicative process in infected cells. During the period of primary infection, the level of viral load is different when infected with different subtypes of HIV, however, the dynamics of its changes are approximately the same. So, when infection with the subtype in, for example, if in the first month after infection, the value of the viral load is 700 copies / ml, then in the 2nd month there is a decrease to 600, in the 3rd - to 100, in the 4th - to 50 copies / ml. Such dynamics is observed against the background of the increase in the blood content of specific antibodies to HIV. The content of surrigated DNA in the blood mononuclears HIV-infected is characterized by relative constancy during the first 6 months with minor fluctuations in some subtypes. Thus, RNA and DNA loads are not identical.
In the incubation stage for some time, specific antibodies for HIV in an amount sufficient to determine existing laboratory methods. Before registration of the antibodies, a very short time is observed in the blood of the NE protein, which represses the replicative process, and the structural protein P24. Antigen P24 can be detected in the blood by immospamental analysis already after 1-2 pedal after infection and determined until the 8th week, then its content decreases sharply. Further, in the clinical course of HIV infection, the second lifting of the blood content of protein P24 is noted. It falls for the period of AIDS formation. The disappearance in the blood of free (not bound by antibodies) core proteins P24 and the appearance of specific antibodies to HIV proteins marked the occurrence of seroconversion (Fig. 9.6).
Viryia and antigenemia cause the formation of specific IGM-class antibodies (anti-P24, anti-GR41, anti-GR120, anti-GR160). Free IGM and IgG IGG antibodies to the P24 protein may appear, starting from the 2nd week, their content rises within 2-4 weeks, reaching a certain level on which it is stored for months (IGM) and years (IgG) (Fig. 9.7).
The appearance of complete seroconversion, when in peripheral blood is recorded a high level of Spex IGG class antibodies to the structural proteins of HIV P24, GP41, GP120, GR160, significantly facilitates the diagnosis of HIV infection. HIV antibodies appear in 90-95% infected for 3 months after infection, in 5-9% - in the period from 3 to 6 months from the moment of infection and in 0.5-1% in the later deadlines.
Despite the fact that the antibodies to HIV appear last, the main laboratory diagnostic indicator to the present is the detection of specific antibodies by the ELISA and immunoblotting method.
The data presented in Table 9.2 [show] and 9.3. [show] This clearly demonstrate the high sensitivity of modern immunoopherapy test systems when determining the antibodies to HIV, superior to the sensitivity of immunoblotting. In some cases, when receiving a primary positive result in ELISA, it is possible to confirm it in immunoblotting only after 2-3 weeks.
| Table 9.3. Example of monitoring seroconversion (N.Fleury, 2000) | |||||
| Moment of determination | Antigen P24, PG / ml | Antibodies for HIV proteins | |||
| ELISA, OP OP / OP KR ** | Immunoblotting | ||||
| Hiv. Duo. | Gen-Screen. | Uniform | |||
| Patient 1. | |||||
| Primary | 17 | 1,24 | less than 1. | less than 1. | * |
| After 4 days | 67 | 1,36 | 1,85 | less than 1. | - |
| In 7 days | * | 2,33 | 6,84 | less than 1. | - |
| After 2 days | * | 6,77 | 15,0 | 4,8 | gP160 |
| Patient 2. | |||||
| Primary | 400 | 13 | less than 1. | less than 1. | - |
| In 5 days | 450 | 18 | 2,11 | less than 1. | - |
| After 10 days | * | 33 | 12,19 | 2,9 | gP160 |
| Note: * - Definition was not carried out ** - the ratio of the optical density of the test sample of serum to critical (threshold) optical density value |
|||||
When examining patients with HIV infection (HIV-infected) using test systems of immunoblonting leading firms in all cases, antibodies are detected to GP160 and P24 / 25, to other proteins of antibodies, in 38.8-93.3% of cases (Table. 9.4. [show] ).
Difficulties with the detection of antibodies in patients with HIV infection may occur during periods of massive viremia and antigenemia, when the available specific antibodies in the blood are associated with viral particles, and the replicative process is ahead of the production of new antiviral antibodies. Such a situation may occur and disappear during the infectious process.
In patients with a breast-weakened immune system, virems and antigenemia appear earlier and persist on high level Before the outcome of the disease. In such patients, there is a low content of free antibodies to HIV, due to two reasons - insufficient products of antibody in lymphocytes and antibody binding by virions and soluble HIV proteins, therefore test systems are required to determine infection increased sensitivity or modifying methods of analysis, providing for the release stage of antibodies from immune complexes.
The most often reduction in the content of antibodies to HIV at the specified reasons occurs in the terminal stage, when the antibodies to the HIV in serum Croweim may not be captured using the methods of immununimal analysis, nor the IMUMUMOBLET method (Western blot). In addition to the appearance of specific antibodies to HIV, the immune response in the first 4 months is characterized by a decrease in the blood content of an infected CD4 + - and an increase in CD8 +-cells. Next, the content of CD4 and CD8 receptors carrying cells is stabilized and remains unchanged for some time. An increase in the content of CD8 lymphocytes is a protective reaction, because The cell-dependent tpotoxicity is implemented with CD8 + -Limphocytes, which are aimed at the destruction of HPV-infected cells. Initially, cytotoxic lymphocytes (CTLs) react to the regulatory protein of the NEF virus, which plays an important role in reducing viral (RNA) load in the plasma of HIV-infected in the first months. Then the CTL response is formed and to others, incl. Structural, HIV proteins, resulting in 12 months after infection, the zpotoxic effect increases significantly.
Schemes laboratory diagnostics HIV infections
Taking into account the dynamics of specific HIV infection markers in practice, it is advisable to adhere to the following laboratory diagnostic schemes in adults (Fig. 9.8-9.10).
The schemes reflect the three main phases of the primary laboratory diagnosis of HIV infection:
- Screening.
- Reference.
- Expert.
The need for several stages of laboratory diagnostics is due primarily to economic considerations. For example, the cost of the immunoblotting method with the help of domestic test systems of one expert study is up to $ 40, the screening (IFA method) is about 0.2, that is, the ratio is 1: 200.
At the first stage (Fig. 9.8), the surveyed is determined by the definition of HIV antibodies with a single immunoassay test system designed to detect antibodies to both types of Virus - HIV-1 and HIV-2.
Manufacturers in the proposed test systems, viral lysate, recombinant proteins, synthetic peptides are used as an antigen base. Each of the listed carriers of antigenic determinants HIV has its own advantages and disadvantages. Therefore, when choosing test systems of approximately equal cost, you should prefer sets with the greatest sensitivity (preferably 100%). Among the test systems of the same cost and sensitivity, it is advisable to dwell on having maximum specificity.
Based on the virus lysate, the first test systems were created for the laboratory diagnosis of HIV infection. In the 1980s, such test systems were characterized by a sensitivity of less than 100% and low specificity manifested by a large amount (up to 60%) of false positive results.
In the formation of the virion in the culture of lymphocytes, its shell is created from the outer membrane and therefore contains antigens of the main histocompatibility complex I and II classes. This circumstance determines the false-positive reactions if antibodies to allohygenic histocompatibility are present in the blood of patients.
Later to obtain a virus, it was proposed to use the culture of macrophages, in which viral particles are formed mainly intracellularly by kinding not from the outer membrane of the cell, but from the membranes of the endoplasmic reticulum. Such technology has reduced the number of false positive results.
Some of the best in the most important characteristics - sensitivity and specificity - enzymes are recognized as a combination of purified viral lysate with synthetic peptides, which represent the most antigenous segments of the virus proteins, or recombinant proteins.
The sensitivity of the test system also depends on the characteristics of other components of the sets. Thus, test systems that use conjugates that recognize antibodies not only class IgG, but also IgM, and Iga, allow you to identify an earlier phase of seroconversion. The use of test systems is promising, with which you can simultaneously determine the antiviral antibodies, and antigen P24, which makes even earlier laboratory diagnostics of HIV infection.
The primary positive result must be rechecked by re-examining the sample in the same test system, but preferably another series and another laboratory assistant. If a negative result was obtained during re-examination, the study is carried out for the third time.
After confirming the positive result, it is desirable to reinstall blood and explore it on HIV antibodies as primary. Repeated blood allows you to prevent the error due to the inaccuracy of the labeling of the tubes and filling out the forms of directions.
Seropositive blood seropogenic stage is sent to reference studies performed using two or three highly-specific IFA test systems. In the case of two positive results, an expert study is carried out by immunoblotting.
Application in the reference diagnostics of immunoopimen test systems, with which you can differentiate specific antibodies to HIV-1 and HIV-2, facilitates further work and allows you to investigate a positive sample at the expert stage immediately using the appropriate immunobloting (HIV-1 or HIV-2) .
The laboratory expert opinion on HIV infection is made only on the basis of the positive result of immunobloting (Western blot). When conducting expert diagnostics, it is necessary to use the Nomenclature of Gene and HIV genes proposed in 1990 (Table 9.5 [show] ).
The specificity of the immunoblot bands should be assessed very carefully and carefully using the results of testing serum (positive and negative), which are carried out in parallel with the study of the experimental samples, and the sample of immunoblot with the designation of HIV proteins (attached by the manufacturer to the test system). The interpretation of the results obtained should be carried out according to the instructions attached to the test system. As a rule, the criterion of positivity is the mandatory presence of antibodies to two proteins (predecessor, outer or transmembrane), encoded by the Env gene, and the possible presence of antibodies to the products of two other structural HIV genes - GAG and POL (Table 9.6 [show] ).
| Table 9.6. Criteria for the interpretation of immunobloting results for HIV-1 and HIV-2 (WHO, 1990) | |||
| Result | HIV-1 | HIV-2. | |
| Positive | +/- strip POL. +/- band Gag. | 2 ENV strips (predecessor, external GP or transmembrane GP) +/- strip POL. +/- band Gag. |
|
| Negative | No HIV-1 Specific Strins | Missing HIV-2 specific strips | |
| Uncertain | Other profiles not considered as positive or negative | ||
In case of a dubious result, it is necessary to enjoy the list of recommendations for the final clarification of the results of immunoblotting (Table 9.7 [show] ).
| Table 9.7. Recommendations for the final clarification of uncertain IMMUNOBLET results (WHO, 1990) | |
| The presence of bands corresponding to HIV proteins | Interpretation of the result, further actions |
| HIV-1 | |
| Only p17 | |
| Only P24 and GP160 | So an unusual picture may occur at the beginning of the seroconversion. Immediate re-examination of the sample should be carried out. If the same profile is obtained, it is necessary after 2 weeks after taking the 1st sample to take a second sample for testing in immunoblotting |
| Other profiles | These profiles (GAG and / or ROL without ENV) may indicate seroconversion or non-comer reactions |
| HIV-2. | |
| Only p16 | Can be classified as negative, additional definitions do not require |
| I env strip in the presence or absence of GAG / ROL | It should be re-testing the same sample, but using another series of reagents |
| Only P24 or GP140 | This unusual profile may occur at the beginning of the seroconversion. Immediate re-examination of the sample should be carried out. If the same profile is obtained, 2 weeks after taking the 1st sample, it is necessary to take a second sample for testing in immunoblotting |
| Other profiles | These profiles (GAG and / or ROL without ENV) may indicate seroconversion or non-specific reactions. |
On the recommendations of the Russian Scientific and Methodological Center for the Prevention and Control of AIDS, the result is positive in the presence of antibodies at least one of the GP41, GP120 proteins in combination with antibodies to other specific proteins of HIV-1 or without antibodies. These Recommendations are made to the basis of the experience of working with sera of children from the in-hospital foci, which often defined antibodies only to one of the virus shell proteins.
The main part of the primary surveyed seropositive patients relates to the phase of persistent generalized lymphadenopathy (PGL) or to the asymptomatic phase. Therefore, on immunoblot (nitrocellulosic strip, on which HIV proteins immobilized) is determined, as a rule, the following combination of antibodies to HIV-1: antibodies to the shell proteins GP160, GP120 and GP41, encoded by the Env genome, in combination with antibodies to the core proteins P24 (protein The nucleocapsid, encoded by the GAG \u200b\u200bgenome) and P31 / 34 (endonuclease, encoded by the POL genome).
Positive reactions only with GAG and / or RL proteins may occur in the case of an early phase of seroconversion, as well as indicate an infection caused by HIV-2, or a non-specific reaction.
In case of obtaining a dubious result, the use of various methodological techniques can be clarified by the fact of HIV infection.
Depending on the technical capabilities (the presence of diagnostic sets and reagents, the equipment of special equipment and training of personnel), an expert laboratory conducts additional diagnostic studies (Fig. 9.10).
In some cases, it is advisable to use molecular genetic methods, allowing to determine the genetic sequences of HIV in serum, in blood lymphocytes or lemph nodes. Verification of the specificity of DNA sequences obtained as a result of PCR can be carried out by hybridization of nucleic acids with specific DNA probes.
Methods of radioimmunoprecipitation (RIP) and indirect immunofluorescence (IFL) can also be used to final verification of serums with dubious results in immunoblotting.
The detection of HIV RNA in the blood plasma is not a high-quality or quantitative method is not significant for the diagnosis of HIV infection. This result must be confirmed standard methods, such as immunoblotting, 2-4 months after receiving the primary dubious or negative response.
The release of HIV in cell culture is the truth in the last instance. However, the method is complicated, roads and is performed only in specially equipped research laboratories.
The content of CD4 + - blood cells is a non-specific indicator, but in controversial cases (IFA + ", immunoblot" - ", clinical signs HIV infection / AIDS) It can be used as a reference point for the adoption of an expert decision. If the laboratory has the ability to perform only immunobloting, then the recommendations set forth in Table should be followed. 9.7 and in Fig. 9.9.
Persons, with an expert test of serum whose dubious (uncertain) results, except in cases of detection of antibodies only to P17 (HIV-1) or P16 (HIV-2), should be re-testing for 6 months (after 3 months). In the case of true HIV infection after 3-6 months, the "positive" speaker is observed in the spectrum of antibodies - additional formation of antibodies to other virus proteins. The false reaction is characterized by preserving for a long time of a dubious pattern of immune blotting or the disappearance of suspicious stripes. If after the expiration of the specified period, the results of repeated immunoblotting will be negative or remain dubious, then in the absence of risk factors, clinical symptoms or other factors associated with HIV infection, a person can be considered seronegative with respect to antibodies to HIV-1 and HIV-2.
False-positive results due to the blood content of antibodies to alloantigenic histocompatibility, which is part of the HIV shell, manifest themselves on the immunoblot in the form of a band at the GP41 and GP31 level. The causes of other nonspecific reactions (for example, to P24, often found in people with autoimmune processes) are not yet clarified.
Improving the production technology of immunodermen test systems made it possible to achieve high sensitivity - up to 99.99%, while the sensitivity of the immunobloting method is 97%. Therefore, negative respete in immunoblotting under positive results in IFA may indicate the initial period of seroconversion, characterized by a low level of specific antibodies. Therefore, it is necessary to repeat the study after 1.5-2 months., That is, the period of time required to complete the seroconversion, achieve the concentration of specific antibodies in the blood sufficient to detect the immunoblotting method.
Positive result (results) of research on the reference or only screening stage of laboratory diagnostics of HIV infection, that is, a positive result in any immunooperment test systemAs a result, not confirmed by expert methods, is interpreted as the presence of cross-response antibodies in the blood. Under the cross-reaction implies the binding of non-specific areas in proteins or HIV peptides used as an antigenic basis in the test system in which a positive result was obtained.
In the absence of immunodeficiency and clinical signs of HIV infection, such persons are considered seronegative with respect to HIV antibodies and should be discontinued.
The final diagnosis of HIV infectious is established only on the basis of all clinical, epidemiological and laboratory data. Inform the patient's diagnosis of HIV infection is right only attending physician.
The main method of confirming (expert) laboratory diagnostics of HIV infection is immunoblotting. However, given its lower sensitivity compared to IFA, a number of researchers have been proposed to use a combination of several test systems for the final determination of the presence of specific antibodies to HIV. For example, G. van der Groen et al. Offered an alternative immunoblotting. A method for checking the positive results of the screening stage of the laboratory diagnosis of HIV infection. It involves the study of the material in parallel in three test systems, which are based on various methods of detection of specific antibodies to HIV (several EIFA variants, agglutination reaction) using antigen of various nature. The authors managed to choose such combinations of test systems, the use of which provides 100% sensitivity of N specificity when compared with the results obtained in immunoblotting.
The cheapness of this method of expert diagnosis is an undoubted advantage, but the lack of information, which specifically the virus proteins have antibodies in the patient's blood, does not allow to evaluate the specificity of the reaction in each individual case, as well as track changes in the spectrum of antibodies at an early stage of seroconversion.
Laboratory diagnosis of HIV infection in children born from HIV-infected mothers has its own characteristics. From the moment of birth for a long time (up to 15 months) in the blood of such children can circulate maternal antibodies to HIV. Only immunoglobulins of the IgG class are penetrated through the placental barrier, so the IGM and IGA-specific NMMMPoglobulins of the IGM and IGA classes make it possible to confirm the infection, but the negative result cannot indicate the absence of HIV.
In children under the age of 1 months, the replication of HPV is not yet, and the only method of verification is PCR. Determination of antigen P24 in children older than 1 month is also a confirmation method.
The absence of antibodies to HIV in newborns does not mean that the virus is not penetrated through the placental barrier. In any case, the children of HIV-infected mothers are subject to laboratory and diagnostic surveys and observation within 36 months from birth.
results laboratory studies on HIV infection markers require cautious interpretation and should only be considered together with the data of epidemiological and clinical examinations. On the other hand, it should be noted that despite the high sensitivity of modern methods, negative research results cannot completely eliminate the presence of HIV infection. Therefore, the negative result of the study, for example, by immunoblotting, can only be formulated as the absence of specific antibodies to HIV-1 and HIV-2.
Diagnosis of HIV infection in seronegative patients
The quality of test systems used in the laboratory diagnosis of HIV infection is improved every year, their sensitivity increases. However, high variability of HIV can lead to new types, antibodies to which may not be recognized by existing test systems. In addition, there are cases of an atypical humoral response of the immune system of the host organism to the virus. So, L.Montagnier in 1996 reported two Patients with AIDS, which during the previously several years have not been identified in the blood of specific antibodies, the diagnosis is made on the basis of clinical data and is confirmed by laboratory only to release HPV-1 in cell culture. In such cases, it is necessary to use WHO recommendations according to which clinical diagnostics HIV infections in adults and children are possible in the presence of one of 12 AIDS-indicator diseases:
- candidiasis of the esophagus, trachea, bronchi, lungs;
- extravalic cryptococcosis;
- cryptosporidia with diarrhea more than one month;
- cytomegalovirus defeat of any organ (except and besides the liver, spleen and lymph nodes In the patient older than 1 month):
- the infection caused by a virus of a simple herpes is persistent more than 1 month in a patient older than 1 month;
- brain lymphoma in patient under 60 years old;
- lymphocytic interstitial pneumonia in a child under 13;
- dissimal infection caused by the bacteria of the MicoBacterium Avium Intracellulare or M.Kansassii group;
- pneumatic pneumonia;
- progressive multi-grade leuko-encephalopathy;
- toksoplasmosis central nervous systemss patients older than 1 month.
The presence of one of these diseases allows you to diagnose HIV infection in the absence of a laboratory testing of blood for the presence of antibodies to HIV or even upon receipt of a seronegative result.
A source: Medical laboratory diagnostics, programs and algorithms. Ed. prof. Karpischenko A.I., St. Petersburg, InterMedica, 2001
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.
For the study, various biological material can be used: serum, blood plasma, scraping, bioptat, pleural or spinal fluid (SMG). First of all, the methods of laboratory diagnosis of 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, cells of nervous tissue, resulting in slowly progressive damage to immune and nervous systems of the body, manifested by secondary infections, tumors, subacted 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 humans with a normally functioning immune system. These are diseases that the World Health Organization (WHO) identified as AIDS marker or AIDS-indicator diseases.
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.
First Group:
- 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.
Second group:
- 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).
Table 1 (see reference to the source above) AIDS-indicator diseases and their etiological agents are given.
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 74 100 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 the content of HIV-1 in the blood\u003e 10,000 copies / ml than those with HIV-1 in the blood<10 000 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 >20,000 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.
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The readiness of the results of the analysis
Normal *: Delivered to 12:00 (11.00 in Podolsk) - 1 working day, surrendered after 12:00 (11.00 in Podolsk) - 2 working days
Deadline for analyzes in express mode (CITO)
| Time for delivery | Readiness | |
|---|---|---|
| Weekdays | Weekend | |
| Clinic with a CIR Laboratory on Dubrovka | ||
| 08:00-12:00 | - | 1 day |
| 12:00-20:30 | - | |
| Marino, Novokuznetskaya, Voikovskaya | ||
| 08:00-12:00 | 09:00-12:00 | 1 day |
| 12:00-20:30 | 12:00-17:00 | The next day, as listed at 8:00 |
| Butovo | ||
| 08:00-12:00 | 09:00-12:00 | 1 day |
| Podolsk | ||
| 08:00-11:00 | 09:00-10:00 | 1 day |
Value of analyzes
Analysis on HIV antibodies (human immunodeficiency virus, HIV, Human ImmunodeFiciency Virus) allows you to identify antibodies that are formed in the body in response to a virus infection.
HIV - human immunodeficiency virus - AIDS microorganism (AIDS (Acquired Immunodeficiency Syndrome)).
Ways to transfer the human immunodeficiency virus
- sexual - with unprotected sex contact with HIV-infected partner. The highest risk of infection with anal sexual contact, the smallest - with oral one.
- contact with infected blood - When using needles, non-sterile tools, when transfusion of donor blood.
- vertical transmission path- from a HIV-infected mother to the fetus during pregnancy, during childbirth, when breastfeeding.
Testimony for survey
- Planned hospitalization
- Preparation for the operation
- Pregnancy and pregnancy planning (included in the survey standard)
- Unprotected random sex contacts, frequent change of sexual partners
- Availability of infection risk factors (for example, medical workers)
- Complaints: an increase in lymph nodes in several areas, night sweats, long fever (temperature), weight loss, long diarrhea,
- Identification of the following diseases or their combinations: tuberculosis, candidiasis, toxoplasmosis, frequent recurrences of herpesvirus infection, pneumonia caused by mycoplasmas, legionells, pneumatic pneumonia, sarcoma capsis.
When to take an analysis on HIV antibodies
- Planned hospitalization, preparation for the operation: check in the medical institution.
- Pregnancy planning: in a pregnancy preparation program.
- Pregnancy: at least three times during pregnancy according to the obstetric calendar.
- In the presence of infection risk factors - at least 1 time per year.
- Estimated infection: the average time of the appearance of antibodies in the blood - 2 weeks from the moment of infection, the maximum is 6 months. Typically analyzes pass through 1, 3 and 6 months.
- If there are complaints and identification of the diseases listed above: immediately.
How to pass tests in CIR laboratories?
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Materials on the topic
When the results are needed quickly, come to any CIR clinic. In the evening, get the results of the tests.
Prenatal screening is not only an assessment of the risk of developing fetal defects, but also assessing the risks of pregnancy complications - in the shortest possible time!
Attention!With positive and dubious reactions, the deadline for issuing the result can be increased to 10 working days.
Antibodies to HIV 1, 2 types, antigen P 24 - study of specific antibodies arising in the body in response to infection with the human immunodeficiency virus (HIV) 1, 2 types and antigen P 24 human immunodeficiency virus.
HIV(Human immunodeficiency virus) - a virus of a family of retroviruses (virus with slow replication), which affects the cells of the human immune system (CD4, T-helpers) and causes an enzyme-acquired syndrome.
The duration of the incubation period is usually 3-6 weeks. In rare cases, antibodies to HIV begin to be found only in a few months or more after infection. The level of their concentration may noticeably decrease in the terminal period of the disease. In rare cases, antibodies to HIV infection can disappear for a long time.
Antigen R 24 HIV 1.2 Type, detected in serum, testifies to the early phase of the disease. During the first few weeks after infection, the amount of virus and antigen R 24 in the blood rapidly increases. As soon as antibodies to HIV 1, 2 begin to produce, the level of antigen P 24 begins to decline.
The definition of antigen R 24 allows you to diagnose HIV infection in the early stages of infection, until the production of antibodies.
The simultaneous detection of antibodies to the HIV-1,2 virus and the antigen of the virus P 24 increases the diagnostic value of the study.
This analysis allows you to detect antibodies to HIV-1.2, as well as antigen p 24 HIV-1.2. The analysis allows you to diagnose HIV infection in the early stages.
Path transmission infection:
- sexual;
- when blood transfusion;
- from the infected mother to the newborn.
HIV infection - a long and heavy disease, which is accompanied by the defeat of the cells of the human immune system; The effective methods of treatment and means of specific prophylaxis (vaccines) have not yet been developed against it.
The source of the immunodeficiency virus is a person. The virus in humans can be isolated from the seed liquid, secrets of the cervix, lymphocytes, blood plasma, spinal fluid, tears, saliva, urine and maternal milk, but the concentration of the virus is different in them. The greatest concentration of the virus is contained in the following biological environments: in sperm, blood, the sevent of the cervix.
The paths that the virus can be transmitted from an infected person to an unrelated, limited.
Ways transfer HIV infection
There are 3 ways to transfer immunodeficiency virus:
- Sex path - is most frequent. Infection occurs when unprotected sexual contact, while the virus penetrates the body through the mucous membranes. Ranks on the mucous membrane, ulcers, inflammation are a probability of infection. In persons suffering from sexually transmitted infections, the risk of infection during contact with an infected person is 2-5 times higher. Not only the degree of intimacy of contact is important to transmit the virus, but also the amount of pathogen. With unprotected sex, the likelihood of infection of a woman from a man is about three times higher, since its body gets more virus, and a woman has a much larger surface area through which the virus can penetrate the body (mucous vagina). The risk of infection is highest with anal sexual contact and least - with oral.
- Contact with blood infected person: a) when using common needles, syringes, dishes for the preparation of drugs, non-sterile medical instruments; b) the introduction of drugs, in the preparation of blood used; c) use, transfusion of infected donor blood and made of it preparations (the risk is extremely low, since all donors, and blood is thoroughly checked).
- From the HIV-infected mother (vertical path) to the fetus during pregnancy, when passing through the generic paths, during breastfeeding.
AIDS - Terminal Stage HIV Infection
AIDS is not developing immediately. In most people with antibodies to immunodeficiency virus, clinical signs of AIDS may not appear from 2 to 10 years and more, and in successful treatment, this term increases significantly. This is due to the fact that there is a sufficiently long time to reduce the amount of CD4 T cells to the level at which the immune system is weakened.
The virus affects other types of cells, including the cells of the central nervous system and the cells of red and white blood, in which the virus, apparently, is in the "dormant" state for a long time before it starts to actively multiply. Factors affecting the progression of the disease are diverse: genetic features, virus strain, psychological condition of the patient, living conditions and others.
The course of the disease and the duration of the stages also depend on whether a person receives treatment, and if "yes", then what drugs.
4 stages HIV infection
- The incubation period ("window period") is the time from the moment of infection before the human antibody (protective proteins of the immune system) to the virus. During this period, the infection does not appear in any way, all analyzes are negative, but the person is already infected. The incubation period can last up to 3 months (on average 25 days).
- The stage of primary manifestations. It continues on average for 2-3 weeks and is characterized by a sharp increase in the number of virus in the blood. This condition is called "seroconversion disease", since at this time the antibody to the virus appear in the blood in quantities sufficient to detect during analyzes. This period in most persons does not appear in any way, however, 20-30% can be celebrated flu-like phenomena: an increase in body temperature, an increase in lymph nodes, headache, throat pain, ailment, fatigue and muscle pain. This state passes after 2-4 weeks without any treatment.
- Asymptomatic period. It comes after the end of the primary manifestations of infection and lasts in the absence of treatment, an average of up to 10 years. During this period in the human body there is a struggle of the immune system with a virus: gradually increases the number of viral particles and decreases immunity. By the end of this stage, infected persons there are an increase in lymph nodes, night sweats, general malaise and the first manifestations of opportunistic infections occurring in humans, with a strong weakening of the immune system. These infections are caused by microorganisms surrounding us and non-infectious people in healthy people. The weakening of the immune system may also lead to the development of other diseases, such as cancer.
- AIDS is the last stage of this disease and is characterized by the emergence of a number of diseases due to the weakening of the body's immune system. As a rule, patients have a very low number of CD4 T; one or more heavy opportunistic infections (pneumatic pneumonia, heavy fungal infection, tuberculosis, etc.), which are caused by death in the absence of treatment; oncological diseases; Encephalopathy (brain defeat, accompanied by dementia development).
The diagnosis of HIV infection is a comprehensive process based on the data of laboratory, clinical and epidemiological examination, and the main role in the formulation of the diagnosis plays a laboratory study of blood.
The main method of laboratory diagnostics is the detection of antibodies to the virus using an enzyme immunoassay analysis.
The procedure for conducting a laboratory study for the presence of human immunodeficiency virus and antibodies to this virus is strictly regulated by the orders of the Ministry of Health of the Russian Federation and includes:
- stage of screening (qualifying) study by immunoferment (IFA) methods allowed for use;
- the stage of the verification (confirming) study by the Immunoblot method in the Laboratory of the City Center for AIDS.
Laboratory diagnostics of immunodeficiency virus in children born from their mothers infected with this virus has its own characteristics. In the blood of children up to 15 months from the moment of birth, maternal antibodies to the virus can circulate (class Ig G). The absence of antibodies to the virus in newborns does not mean that it is not penetrated through the placental barrier. Children of mothers infected with immunodeficiency virus are subject to laboratory and diagnostic surveys within 36 months after birth.
Prior to obtaining a positive result in immunoblot and, under the negative result of the study, a person is considered healthy and anti-epidemic events are not conducted with it.
The material for the study on antibodies to the immunodeficiency virus is venous blood, which is desirable for an empty stomach.
Of course, the test for the presence of a virus is the voluntary case of every person. Analyzes on the carrier of the immunodeficiency virus cannot be applied forced, without the consent of the patient. But you need to understand that the larger the correct diagnosis will be made, the more likely to live a long and full life, even being its carrier.
Indications:
- an increase in lymph nodes of more than two regions;
- leukopenia with lymphopenia;
- night sweating;
- sharp weight loss of an unclear cause;
- diarrhea for more than three weeks of unclear reasons;
- fever unclear causes;
- pregnancy planning;
- preoperative preparation, hospitalization;
- identification of the following infections or their combinations: tuberculosis, manifestic toxoplasmosis, often recurring herpes-viral infection, internal organs candidiasis, re-neuralgia herpes-zoster, caused by mycoplasmas, pneumatic or legionells pneumonia;
- sarcoma Caposhi in young age;
- random sex contacts.
Blood is recommended in the morning, from 8 to 12 hours. Blood takes on an empty stomach or 4-6 hours of starvation. It is allowed to use water without gas and sugar. On the eve of the study, food overloads should be avoided.
Rules for HIV:
Registration of applications for conducting research in the DNCC is carried out on a passport or a document replacing it (migration card, temporary registration at the place of residence, certificate of a serviceman, certificate from the passport table with a passport loss, registration card of accounting from the hotel). The presented document must necessarily contain information on the temporary or permanent registration in the territory of the Russian Federation and the photo. In the absence of a passport (document replacing it), the patient has the right to issue an anonymous application for the delivery of biomaterial. With an anonymous examination, an application and a client received from the client, a number of biomaterial is assigned a number known to the patient, and the medical staff, which made out the order.
The results of research performed anonymously cannot be submitted for hospitalization, professional inspections and are not subject to registration in a gun.
Interpretation of results
Test for antibodies to HIV 1/2 is high quality. In the absence of antibodies, the answer is "negative". In case of detection of antibodies to HIV, the study is repeated in another series. When repeating a positive result in an immunoformal test, the test is sent to the confirmation of the Immunoblot method, which is the "gold standard" in the diagnosis of HIV.
Positive result:
- HIV infection;
- a false positive result requiring repeated or additional studies *;
- the study is non-informative in children under 18, born from HIV-infected mothers.
Negative result:
- not infected (compliant diagnostic time analysis);
- sernegative version of the flow of infection (antibodies are late);
- terminal stage of AIDS (violated the formation of antibodies to HIV);
- the study is not informative (diagnostic time not complied).