Immunochromatographic test
Since the first AIDS test reagent was introduced in 1985, AIDS testing has become more and more simple, sensitive, rapid, without special equipment, and the results can be observed directly with the naked eye. AIDS test strip is a test technology developed on the basis of ELISA method, because of its simple operation, fast, single copy test, easy to save, do not need special equipment and other advantages, is also widely used in clinical screening of HBsAg, emergency and blood donation site screening has its practical value, can avoid the waste caused by ineffective collection of blood, saving a lot of manpower and material resources, so more suitable for emergency and blood donation site screening, can avoid the waste of ineffective blood collection, saving a lot of manpower and material resources. Therefore, it is more suitable for emergency and non-remunerated blood donation on-site screening.
The Colloidal Gold (Gold Standard) Antibody Test for Human Immunodeficiency Virus (HIV 1/2) is a sensitive, specific and easy-to-use one-step qualitative test for the detection of HIV 1/2 antibodies using colloidal gold immunochromatography. It is used for the qualitative detection of specific antibodies to HⅣ type 1 and HⅣ type 2 in human serum or plasma samples to assist in the diagnosis of HⅣ infections, and its positive results need to be confirmed by immunoblotting. It is characterized by its convenience, rapidity and high sensitivity, making it the most convenient and fastest way to screen for AIDS patients. At the same time, this very high sensitivity leads to the possibility of false positives with the reagent.
Classification of a blood test (whole blood, serum) test paper, a saliva (gum scale exudate) test paper. Blood test paper generally have imported reagents: Abbott (serum), SD (whole blood); domestic reagents: Aikang (serum), Ai Zhi (whole blood), etc.
Saliva test paper saliva test paper is currently more recognized globally is the U.S. Klipton company's AWARE Ai Wei brand.
Enzyme-linked immunosorbent assay
The basic principle of the ELISA method is that the immune reactant forms an enzyme conjugate by chemical or immunological methods, and the enzyme conjugate can bind to the corresponding antigen or antibody in the sample to be examined to become an immune complex, and then add an enzyme substrate, the enzyme catalyst or hydrolysis of the enzyme, and a colorless substrate produces a color, and the results are observed with the naked eye and spectrophotometer. The HⅣ ELISA reagents for primary screening have now been developed into the fourth generation of detection reagents. The first generation reagents mainly use viral lysates or partially purified viral antigens to encapsulate the reaction plate to detect antibodies in the serum. Since the encapsulated antigen is not very pure, the false positive rate is high. The second generation reagents use recombinant antigens and synthetic peptides obtained by genetic engineering methods to encapsulate the reaction plate, and the specificity is greatly improved due to the use of purified antigens. The third generation reagents use a double antigen sandwich method to detect antibodies, further improving sensitivity. The fourth generation of reagents further increased the detection of P24 antigen on the basis of the third generation, the HⅣ antigen and anti-P24 antibody were coated with the reaction plate at the same time, and the HⅣ antibody and P24 antigen in serum could be detected at the same time. Immunoblotting test
Immunoblotting test is mainly used for confirmation test, the basic principle is that HIV whole virus antigen after electrophoresis, the molecular weight of the protein bands of different sizes to separate, and then these have been separated from the different protein bands of electrostatic transfer to the nitrocellulose membrane. This membrane is cut into strips, and each strip of nitrocellulose membrane contains the electrophoretically separated HIV viral antigen. The serum sample to be examined is diluted to 1/100 with diluent, and then it is added directly to the nitrocellulose membrane and shaken at a constant temperature to make full contact reaction. The serum, if it contains anti-HIV antibodies, will bind to the antigenic bands on the membrane strips. After adding anti-human IgG enzyme conjugate and substrate, it can make the reactive antigen? The antibody-binding band takes on a purplish-brown color, and the result is determined by the appearance of the band. The specificity of the immunoblot test has been reported to be not very good, with a false-positive rate of about 2%, but the immunoblot test is still the most commonly used HIV confirmation test today.
With HIV infection, one can determine if one is indeed infected through a process of rapid testing-primary screening tests-confirmation tests. The rapid test or the initial screening test alone cannot achieve a confirmatory effect. If you exclude the effects of some hormonal drugs, two or more rapid tests can be used to determine the general state of your health. After years of evaluation by the U.S. National CDC and UNAIDS, as well as several large sample size studies. Two or more HIV screening reagents applied simultaneously to subjects who meet the window period provide a clear indication of their health status. Both reagents show negative, can be judged as a negative HIV status; both reagents show positive, can be judged as suspected positive may be infected with HIV status, need to be confirmed through the confirmation test to give a confirmed result; a negative and a positive and then through the confirmation test way to give a confirmed result.
China's blood collection and blood supply institutions, as well as the routine screening tests in health care institutions require the use of antibody sandwich ELISA, in remote areas where AIDS screening laboratories have not yet been set up, or for health care institutions in need of emergency surgery, emergency delivery, and VCT, or it is estimated that it is difficult to follow up to the object, can be used rapid method of blood samples for screening. Screening of blood and blood products must be done using a combination of HIV-1 and HIV-2 reagents. If the test result is negative, it can be reported as free of HIV infection after the window period is excluded; if it is positive, it should be retested using the original reagent and another reagent with different principles or from a different manufacturer, and if both reagents are negative, it will be reported as a negative antibody test, and if it is both positive, or one is negative and the other is positive, it will need to be sent to a confirmatory laboratory for confirmation.