HIV Antibodies 1 & 2 with P24 Antigen Blood Test

About the test

The HIV antibody tests checks for the immune response to an HIV infection. It checks for HIV 1 (which is found world wide) and HIV 2 (which is predominantly found in West Africa). Because there is a delay between infection and the development of antibodies, if infection has occurred recently, the test may still be negative. This is referred to as the ‘window period’ and can last up to 90 days. It is therefore often recommended that, if you believe you have been exposed to HIV but the test is negative, you repeat the test after 90 days.

The P24 test actually tests for a protein produced by the HIV virus. This can usually be detected before the antibodies are produced (usually 2-3 weeks after infection) and can therefore allow for earlier detection. The protein disappears from the blood once antibodies are produced and therefore the test becomes negative (usually after 1 – 2 months).

3 Biomarkers