HIV ag/ab tests for HIV p24 antigen in addition to antibody. This is a test that is intended for use in screening early/recent infections. If you had an exposure recently and 6 weeks has past, this is the test to take. If you had an exposure a while ago, and it has been more than 8 weeks, some would even say 6 weeks, the regular Elisa is the test to take as at that point, p24 will be undetectable or too small in amount to be detected by the ag/ab test. That said, the ag/ab test is more sensitive in general than the standard Elisa. Be careful though, it's all about timing. I got a false positive on an ag/ab test and I took it long after 3 months and it scared. the. crap. out. of. me. Remember, ag/ab at 4-6 weeks, Elisa after 6+ weeks(ideal at 3 months).
· 8 years ago