Question: Hi,
I e-mailed Dr. XXXXXXX Bhavsar 3 weeks ago here on HC Magic about my worries about false positive HIV tests, particularly some research I found saying that flu shots and allergy shots could increase the risk of false positives. At the time, I was too afraid to get the STD testing done. So I went ahead and got a flu shot early Oct and my allergy shots 10/9. However, I still would feel relieved if I did the test and it came back negative. How likely are flu and allergy shots to cause a false positive – either on the ELISA or more specialized tests? How long would you recommend waiting ideally after the flu and allergy shots? I only get the allergy shots once a month and I could even push that a little longer if needed. Or is there almost no risk of false positives?

Note that I don’t have any actual STD symptoms. I just have substantial health anxieties and for a long time have wanted to get this testing done but been extremely afraid to do it. Would the antigen and nucleic acid tests be vulnerable to false positives from flu or allergy shots or is it just the screening antibody tests like the Elisa? Although I could get the test right away, my history is low risk. I’ve had only a few instances of heterosexual protected sex (5 to 10 years ago) and one many (about 15 years ago) that was unprotected. I haven’t shared needles or had a blood transfusion or had any other risks either. This is mostly just an irrational fear on my part but I want to at some point do the tests so I can feel better. It’s hard to explain but I’ve started dating and I was hoping to be able to say to a new partner that my test results are all negative and to find out if hers are. Thanks for your help.

OK - Thanks. Just to clarify: Were you saying that you would wait 6 to 7 weeks after the shots for the PCR test and then a little longer for the Elisa (rather than doing it now)? Would the PCR be very unlikely to come back falsely positive or indeterminate even now rather than waiting 6 to 7 weeks?