[Question #9423] HIV test

32 months ago

I did an HIV test yesterday. Here is what I have in my lab report: HIV 1&2 Abs/P24 Ag screen Not detected

I heard about the first, second, third and fourth generation HIV tests. What do these terms mean? Was my test a fourth generation test? Was my test a third generation test? Was my test a second generation test? Was my test a first generation test?

Thank you!

H. Hunter Handsfield, MD

32 months ago

Welcome to the forum.

HIV experts no longer use the "generation" terminology to describe the HIV blood tests. "First generation" refers to the original HIV antibody tests developed about 30 years ago and no longer in use. They were replaced by improved "second generation" tests about 20-25 years ago. These in turn were replaced by "third generation" antibody tests 10-15 years ago, and very soon after that the "4th generation" tests, which detect both HIV antibody and antigen came along. The only difference between third and fourth generation is in detection of early infection: negative 3rd gen tests are conclusive 8 weeks or more after exposure, versus 6 weeks for 4th generation, i.e. the AgAb tests.

Your test is 4th generation, i.e.an antigen-antibody or AgAb test. If it was done more than 6 weeks after your last possible exposure to HIV, it proves you were not infected. ("Not detected" means negative.) If you would like to describe the nature of the exposure you are concerned about and when it happened, I would be be happy to comment further about the reliability of your test result.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

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