HIV Duo test - reliable or not?


Dear Dr. Bob,

hello from London town. Firstly - great website! Secondly - apologies if this has already been answered in the archives.

I had sex with a sex worker in Cape Town, including a couple of minutes protected (as far as I remember!) penetrative vaginal sex.

I had a whole raft of tests 29 days after, including the HIV Duo - the P24 antigen and the standard HIV test. Apparently reliability is over 99%. Results were negative.

The only reason I'm getting a bit concerned is that at 6 weeks post sex I got a chest infection which took 2 weeks to shake. I had a week's respite and I then havecome down with another viral infection which i've had for the last 9 days and just does not want to go.

My questions are as follows:

  1. Do you agree with the stats for the effectiveness of the Duo test?
  2. Is 6 weeks post "exposure" usually too long to get primary ARS symptoms and are they usually worse than a chest infection?
  3. Should I test at 90 days or stop being a muppet and woo-hoo?

Cheers & God bless - donation on the way!!



Hi GR,

  1. The published guidelines continue to recommend HIV-antibody testing at the three-month mark. Certainly the newer testing assays are getting better at detecting HIV earlier, but I cannot confirm the reliability statistics you mention in your question.

  2. Acute retroviral syndrome (ARS) symptoms generally manifest themselves at two to three weeks after primary HIV infection. An isolated "chest infection" at six weeks is not consistent with HIV ARS.

  3. I'd recommend both!

Thanks for your donation to The Robert James Frascino AIDS Foundation ( In return I'll send my good-luck/good-health karma that your definitive three-month test remains negative. (I strongly anticipate it will.)

Good luck.

Dr. Bob