Laboratory tests for AIDS mainly include HIV antibody, HIV nucleic acid, CD4+ T lymphocytes, and HIV genotype drug resistance testing.
HIV1/2 antibody test is the gold standard for the diagnosis of HIV infection; HIV nucleic acid quantification (viral load) test and CD4+ T lymphocyte count are two important indicators to determine disease progression, clinical medication, efficacy and prognosis; HIV genotypic drug resistance test can provide scientific guidance for the selection and replacement of highly effective antiretroviral therapy (HAART) regimen.
I. Antibody testing
The main tests are enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA). ELISA uses decontaminant lysed H IV or infected cell fluid extract as antigen, and IFA uses infected cell smear as antigen for antibody detection. To prevent false positives, Westernblot (WB, protein blotting) can be done for further confirmation.
The WB method uses polyacrylamide gel electrophoresis to separate H IV proteins, and then transfers different protein bands on nitrocellulose membranes by transfer electrophoresis. After incubation with patient serum and staining with anti-human globulin enzyme-labeled antibodies, antibodies against different structural proteins, such as anti-gp120, gp41 and P24 antibodies, can be measured with high specificity.
The rapid detection method, also known as the gold standard method, is also a method of antibody detection, based on the principle of immunochromatography, for the qualitative detection of H IV antibody detection.
Second, antigen detection
ELISA detection of P24 antigen, the antigen is present in the blood in the early stages of H IV infection when antibodies have not yet appeared. Because the amount of P24 is too small, the positive rate is usually low. The existing dissociated immune complex method or concentrated P24 antigen to improve the sensitivity.
III. Nucleic acid detection
PCR method (polymerase chain reaction method) to detect H IV gene, with the advantages of rapid, efficient, sensitive and specific, the method has been used in the early diagnosis of H IV infection and AIDS research.
IV. Virus isolation
Commonly used method for co-culture method, that is, using normal human peripheral blood isolated single nucleated cells, plus PHA (polyhydroxy fatty acid lipid) stimulation and culture, added to the patient’s single nucleated cells in the diagnosis and research of AIDS.
V. Test strip detection
HIV test strips are a new generation of testing reagents developed using colloidal gold immunochromatography technology. It detects H IV-1/2 specific antibodies in serum or plasma specimens. All operations take about 15 minutes and are easy, rapid, accurate, and come with quality control. Suitable for major hospitals, CDC screening.
1.Applicable to: clinical testing, non-remunerated blood donation site screening, etc.
2.Objective: Fast, convenient and accurate diagnosis of HIV infection.
3.Operating time: about 15 minutes.
4.Advantages: simple, rapid, accurate, self-contained quality control control.
There are two common types, one is blood test paper, one is saliva test paper.
Blood test strips are generally Abbott, Aiken, Jinhao Wantai, etc., of which Abbott is the better AIDS test strips. Saliva test strips have a kind of saliva test strips of American Averill, the regular HIV test strips production batch number can be checked by the State Food and Drug Administration.
Because high-risk groups focus on privacy protection in HIV testing, so HIV test strips have become a more acceptable testing method for high-risk groups. And it is worth reminding that although the online test strips can be purchased completely anonymously to protect one’s privacy, without the professional operation of medical personnel and the analysis of personal situation and disease promotion, even after the self-test results come out, one will still have doubts about the accuracy of the test strips. Then it is better to go to the CDC for testing, which provides professional counseling services in addition to free testing services.