I am sorry to ask a new question immediately. I am grateful for your work on this forum. As Dr HHH mentioned, I will consider making a donation to the ASAH.

Dr HHH's last reply made me really anxious and confused. I find online the CDC's publication on the window period of HIV tests: https://pubmed.ncbi.nlm.nih.gov/27737954/

There is the following statement in the introduction of the above publication: 

Third-generation tests use conjugated synthetic peptide antigens and detect both IgG and IgM (IgG/IgM sensitive). The latest advancement includes tests that detect p24 antigen and anti-HIV-1/HIV-2 IgG and IgM (Ag/Ab assays).

But Dr HHH said that not all AgAb tests have an IgM component? I am really confused. I thought that the IgM component would reduce the window period. If some AgAb tests have no IgM component, how can you be so sure that they "all perform equally reliable, with conclusive results on the same time frame"? Do you mean that the IgM component is useless?

For myself, I did my HIV 1&2 Abs/P24 Ag screen test in the UK and now I am in the US. I can't verify with the lab because they don't respond to my calls. I really want to avoid further tests if possible. Further tests will make me very anxious. My questions are:

1. Can you please clarify the above?

2. Can I be 100% sure that my HIV 1&2 Abs/P24 Ag screen test (sample from my arm, I don't know it was a lab-based test or a POC test) at 8 weeks is entirely conclusive?

I did not say not all AgAb tests include IgM testing, only that I'm uncertain. What I wrote was "I'm not sure whether all AgAb tests have an IgM component."

I also advised that if you remain concerned about it, you can determine exactly what test was done -- I do not believe it is impossible for you to learn from the lab exactly what HIV test they do routinely, whether online, by phone, or your doctor's office (if the test was ordered by a doctor or clinic). However, I also went out of my way to tell you that this simply doesn't matter:  every HIV AgAb test has been studied and found to be equally reliable as to the results. Why does IgM not matter? Because the test detects both antigen and antibody, and that combination -- whether or not the antibody component includes IgM -- is always conclusive by 8 weeks. There has never been an reported exception (not counting people who took anti-HIV drugs as post-exposure prophylaxis).

Or feel free to be retested at this time if you remain unconvinced.

HHH, MD