Which generation of HIV test

Currently, HIV testing mainly relies on third- and fourth-generation tests, with fifth-generation tests emerging as a new technology. Different generations vary in terms of detection targets and window periods, allowing selection based on individual needs. The details are as follows:

Third-generation tests detect antibodies to HIV-1 and HIV-2. This method is mature and stable, with accuracy exceeding 99.5% after the window period. The window period is approximately 3–4 weeks, making it a common choice in most hospitals in China. Fourth-generation tests add detection of HIV-1 p24 antigen to antibody testing, shortening the window period to 2–3 weeks, enabling earlier infection detection, with accuracy above 99.9%. However, the cost is relatively higher.

Fifth-generation tests can simultaneously detect and differentiate p24 antigen, HIV-1 antibody, and HIV-2 antibody, providing more precise results and representing the latest advancement in testing technology. The first two generations have largely been phased out due to limitations. Although nucleic acid testing (NAT) does not fall within the generational classification, it has a window period of only 1–2 weeks and is often used for early screening.

After high-risk exposure, it is recommended to prioritize fourth-generation or nucleic acid testing for early detection, followed by confirmatory testing after the window period. Testing at accredited medical institutions, combined with appropriate timing and personal circumstances, ensures reliable results and effective protection of health.