hiv testing

[fisherman137]

I had an unprotected vaginal sex, one night stand with a lady i just met and i got scared b/c i noticed that the next day i had little wounds on my penis from her giving me a handjob before the sex, i was extremely worried so I got tested with a pcr test and antibody test at 4 days, 10 days, 18 days and at 5 weeks. all the tests came back negative. am i safe now that i got both tests done and all came back negative at those times? thanks

[Willl]

I know the specificity of the ELISAs has gotten a lot better, but I was thinking more in terms of false negatives by the confirmation tests from it being too early since infection. But the confirmation tests must be of comparable sensitivity to the ELISAs, since you say it has been so long since a false positive was given on an ELISA, (implying that the confirmation tests have been picking up true early infections as well).

[H. Hunter Handsfield, M.D.]

False positive results are almost unheard-of with current lab-based ELISAs.  To my knowledge there hasn't been one in the Seattle STD clinic in the past 2-3 years.  (That is the main improvement of "3rd generation", i.e. newer tests, compared with older ones--not the shorter seroconversion window that generates so much conversation on this forum.)  If a FP result does occur, there is no hard and fast rule about what patients are told.  Most of the time, we would tell the patient the results, so they can expect it (and not be overly frightened) if it occurs again with future testing.  But if such a patient doesn't call or return for the test result, we wouldn't spend a lot of time and energy to find him or her.  

All that applies to lab-based testing.  False positives are more common with rapid (Orasure) testing.  It is one of the reasons that rapid testing isn't the automatic first choice in all settings; there is considerable risk of stress for both patient and provider as they wait a couple days for repeat test results.

HHH, MD

[Willl]

When you recommend the 4 to 6 week test in replies like this, I figure you are you basing that partly on the confirmation tests currently being used? I am kind of missing the boat on these very sensitive ELISA's. Isn't it correct that most Dr.'s would just tell you the test is negative, so you would never know if the ELISA was positive and the WB or IFA caused the negative?

Say at your clinic, if someone was tested and the ELISA was positive and the confirmation was negative, do you tell them the test was negative but ask them to come back later in case the confirmation test hasn't picked up the infection yet?

[H. Hunter Handsfield, M.D.]

As many STD Forum regulars know, a lot of my replies expend much energy to explain to frightened people how low the risk is that they acquired HIV.  But people should not take home a general sense that I minimize the risks.  You can't judge my overall perspective based on my replies to frightened people in obviously low-risk settings.

Based on a quick look, it is obvious the website you quote is biased.  The research studies cited are highly selected, compared with others that are available and many are older and have been outdated by more recent research.  At least one source (Michael Fumento, who wrote a book called The Myth of Heterosexual AIDS) is just plain crazy.

It is true that data on transmission risk are biased by the great variability in patients' histories of risky lifestyles and events.  (See my comments about this in the discussion on oral sex started earlier today by username raks.)  However, most non-injection drug using heterosexual men who report vaginal sex as the route of exposure are providing accurate.  Further, the levels of HIV in the population in many developing countries could not have gotten there without relatively efficient female-to-male transmission by vaginal sex.  Female to male transmission indeed is less common in the US than in places like India, subsaharan Africa, and so on--but the 5 in 10,000 (i.e., 1 in 2000) probably is about right; and in some circumstances the transmission risk is mugh higher than that.

Thanks to montrealer for the opportunity to address this.

HHH, MD

[montrealer]

Dear Dr. HHH,

I have read in a acouple of articles online mainlyh on the UCSF website, that the riske of female-to-male transmission of HIV is virtually close to zero. (a lot less than the reported 5 to 10000). This is assuming that the only risk of exposure was unprotected penile to vaginal intercourse, and no toher STDS were present. They say that many of the reported cases by CDC does not take into account other risky behavious such as bisexuality or needle injection. and they record what the patient has just told them.

You have been in the field long enough, and your word on this matter is very apprciated.

http://www.rethinking.org/aids/cite/topic_224.html

Thanks

[wwarrior]

4, 10 and 18 days antibody don't say much but a 5 weeks negative is pretty encouraging.  The Doc might say that given the sexual event that you describe added to your 5 weeks negative, you should be pretty solid.  Average time to seroconversion is 22 days. People who are going to show up positive start to do so at 3 weeks and  the vast majority by 6 weeks.

[H. Hunter Handsfield, M.D.]

Wow--a PCR and 4 antibody tests after a single episode of vaginal sex??!!  You wasted a lot of money.  Had you come to my clinic, the most we would have done is a single HIV antibody test 4-6 weeks after exposure.  The risk of catching HIV from any single episode of vaginal sex is too low to be worth all that testing, regardless of the apparent hand-job trauma.  The chance your partner had HIV probably was very low, and the chance you would have caught HIV--even if whe was infected--probably was 1 in 1000 or less.

Anyway, at this point, with those test results you can be 100% certain you don't have HIV.  Some experts recommend final testing at 3 months, but it really isn't necessary in my opinion.  But if you want to research this further, search this forum's threads and archives for "time to positive HIV test".

Good luck--- HHH, MD