[Question #2885] False Positive HIV Tests: Autoimmune Diseases

41 months ago
Hello Dr. Hook or Dr. Hands field,

I have an anxiety disorder.  Over a year ago, I traveled to Thailand and met an American girl and she gave me oral; no sex because we didn't have protection.  Feeling guilty I talked with her and she said we was 100% clean.

This put me into a cyclical anxiety spiral that had me concerned that a week prior to this, I'd been out drinking and made out with another girl on a beach.  I remember everything from that night (we just kissed a little), but anxiety wants me to believe I blacked out and definitely blanked out a major event like having sex.  Silly.  I know.  And I don't believe it either.

To ease my concerns, I tested 9-10 weeks after both events with 4th gen HIV test and general std panel.  Everything negative.  I can believe these results as conclusive, correct?  I moved on from this and met a girl at home that I care about tremendously.

I  currently have concerns that I am having symptoms of an autoimmune disease (pitting nail, GERD, achy joints, etc.), but I like to be screened for STDs annually as part of my health check up.  I have read that people with autoimmune disorders are are higher risk of receiving false positive HIV results.

Is this true?  How much added risk is there?  I would struggle with a false positive from an anxiety perspective.

Is it even worth the risk for me to get tested for HIV today since my last results were negative 9-10 weeks after my last "risky" episode(s)?

Thank you kindly :)
Edward W. Hook M.D.
Edward W. Hook M.D.
41 months ago
Welcome to our Forum.  I'll try to help but, as you already suggest, addressing your anxiety issues will be an important part of dealing with your concerns.  Hopefully the information I am about to provide will be helpful.

The encounters of concern that you describe are virtually no risk for HIV.  Your partners sound to be relatively low risk, HIV is a rare disease, and, most importantly, there has NEVER been a case proven to be acquired as the result of receiving oral sex or from kissing.  You are not going to be the first.  Further, your HIV test 9 weeks ago proves that you were not infected through the exposures you describe.  HIV test results are entirely reliable at 9 weeks and beyond.  For this reason, there is no medical reason for you to seek further testing related to these encounters.

False positive tests for HIV are rare and I am not aware of data to suggest that they are more common among persons with autoimmune diseases than other groups. This is a different situation than for blood tests for syphilis which (slightly) more often give false positive results in persons with autoimmune disease. 

Finally, I congratulate you both on your commitment to safe, condom protected sex with casual partners and your practice of annual sexual health, STI screening.  In combination these two practices will keep you safe.

I hope my answers are helpful.  Please don't worry about the encounters you have described. EWH
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41 months ago
Thank you Dr. Hook!

The more risky encounter would have been with the first girl (if I did indeed have a case of amnesia and had unprotected sex with her)...so unlikely that I would not recall any memories of something like that given the small things I do recall, lol.  Anxiety does amazing things to the power of imagination.

Regardless, I tested 10 weeks after that particular encounter and as you say, that test is conclusive :).  An abstract to an article I found says the probability of a false negative 4th gen test is the same as receiving a false negative 3rd gen test at 42 days and 80 days post exposure, respectively.  The probabilities were obviously extremely low in those time ranges.

My recent concern is that my current girlfriend gives me oral and ends up swallowing... I don't like that she does this and I'm embarrassed to divulge that information.  However, my anxious mind worries of risks to her because of my poor choices in the past.  Anyways, I need to put that behind me.

A few things I read on the internet says that false positives can be the result of multiple pregnancies, autoimmune disorders, etc.  I will fall to your expertise in this matter; false positives are rare, autoimmune diseases are not rare. 

Based on that, should I continue my annual screenings without worry about receiving false positives?

I promise this will be my last inquiry :)
Edward W. Hook M.D.
Edward W. Hook M.D.
41 months ago
I would encourage you to continue your regular check ups and not worry about false positives.  you have not had any to date and it is unlikely that you will.

That your girlfriend swallows is a no risk event for her and for you.

Finally, I would caution you about going to the internet as a source of health information.  While a great means of communication, the internet is a poor place to go for medical information.  Much of what is said their is taken out of context, misinterpreted or just plain wrong.  The correlates of false positive blood tests that you mention are commonly mentioned in relationship to falsely positive tests for syphilis but I would hesitate to generalize that to HIV tests without more data. 

You may ask up to one more follow-up question

I hope this helps.  EWH
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