[Question #10578] Testing Windows

21 months ago

Good morning Dr's

I am sure you are aware of the amount of discrepancies between PHC providers regarding testing windows for conclusive results. As this is the case I am hoping if you would be so kind to provide them below, so I can refer to one source in the future.

HIV

Hepatitis A B C

Syphilis

Gonorrhea (urine and swab - throat and rectal)

Chlamydia (urine and swab - throat and rectal)

If there any others I have missed it would be great for you to include them.

H. Hunter Handsfield, MD

21 months ago

Welcome back to the forum.

You will find less variability in advice about STI testing, including the time from exposure to positive results ("window period"), if you limit your searching to professionally run sites (like CDC, public health departments, academic institutions) or at least professionally moderated ones (llke this forum). It's best to avoid sites run by and for infected or worried persons (like reddit), and for sure do not rely on individual stories from people who have personal beliefs that don't fit with professional sources. The only test I added that you ddin't mention, but common

HIV: For the main test usually used, i.e. the HIV antigen-antibody (AgAb, "4th generation) blood tests, it's exactly as you were informed by Dr. Hook in your most precent past thread. Usually conclusive at 4 weeks (98% of the time), but on rare occasions it can take 6 weeks to a conclusive result. Combination results can be truly conclusive as soon as 4 weeks: for example, negative RNA (viral load) testing at 2 weeks plus negative AgAb test at 4 weeks is conclusive.

Viral hepatitis: In general 6 weeks is sufficient, but it depends on the specific kind of test and other factors. If you have had the hep B and/or hep A vaccines, you'll never need testing for either one, regardless of what exposures you might have.

Syphilis: In absence of symptoms, most experts consider 6 weeks conclusive but some believe that on rare occasions it can take up to 3 months, and that is the recommendation from some reliable sources. On this forum, we stick with 6 weeks. If there ARE symptoms of newly acquired syphilis (usually the ulcer called a chancre), the tests always are positive within 10 days of onset of the chancre, even if that time is well before 6 weeks since exposure.

Gonorrhea: 2-3 days for all specimen types and anatomic sites.

Chlamydia: 4-5 days for all specimen types and anatomic sites. Since chlamydia and gonorrhea testing almost always are done at the same time, for both infections it's usually best to wait until day 4-5.

You don't mention herpes (HSV) blood tests, but since they are commonly done: First, only have tests for IgG antibody; the IgM antibody tests are always unreliable and should never be done. The IgG tests have a 3 month window, but even then sometimes never become positive, especially for HSV1.

Let me know if anything isn't clear.

HHH, MD

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21 months ago

Thanks Doctor,

So with regards to HIV should I wait 6 weeks if I am a MsM? Or can I be safe with 4 week

H. Hunter Handsfield, MD

21 months ago

I have other information that may interest you -- more information about your two threads a little over a year ago. Since then, an important research study was published -- based in the Seattle STD clinic that I once directed and Dr. Hook co-directed. Among men who have sex with men who denied receptive anal sex (i.e. no bottoming) for the previous two years, rectal testing was positive in 10% for chlamydia and in 4% for gonorrhea. Many of these men had experienced rectal play (sex toys, fingering, oral-anal contact, etc). It is also possible that some falsely denied receptive anal sex, but that wasn't believed to be the main explanation. As discussed in your two threads, a few -- but only a few -- may have acquired infection orally that later showed up with a positive rectal test. Here's a link to that research report: https://pubmed.ncbi.nlm.nih.gov/36943790/

In other words, your situation last year probably was not as unusual as Dr. Hook and I said it was. In any case, your positive test result probably was true positive, not false. I assume you were treated with doxycycline, as we advised -- but you never said explicitly that you had been treated.

Let us know if this information raises any more questions for you about that situation.

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H. Hunter Handsfield, MD

21 months ago

We were writing these second messages at the same time.

If you're having an AgAb test, wait 6 weeks. If you have both an RNA test around 2 weeks and an AgAb test at 4 weeks, those negative results also are conclusive.

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21 months ago

Thanks I was fully treated and retested which was negative thanks for the additional information and I can confirm I never engaged in anal sex but I did so self play with toys so not sure but I appreciate the follow up. Does the new information change your previous advice for risk to my hetero partner?

H. Hunter Handsfield, MD

21 months ago

That aspect is unchanged; your female partner was not at risk.

Presumably the self-play toys had recently been used by other persons (?). It would be unusual to acquire any infection if it had been long enough for any contaminating fluids or feces to have dried out.

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21 months ago

Thanks Doctor, yes some were shared but cleaned and dried before I used so i am still a little perplexed.. im sorry its a bit of a strange one regardless I've been treated and cleared and will continue to practice as well as I can safe sex.

21 months ago

Can I just seek clarity on the different types of HIV tests?

I understand there are rapid tests, duo tests but what are the different tests and when are they appropriate

21 months ago

I've had no luck with GPs to undertake an RNA but a private lab will do it... is this the correct test?

HIV Viral Load.
The viral load is then used to monitor the effectiveness of antiretroviral treatment (ART) over time. HIV viral load testing measures the amount of HIV genetic material (RNA) in the blood and reports how many copies of the virus are present.

And am I correct that I do this 2 weeks post possible exposure and 2 weeks later a standard 4th gen hiv test for conclusive results?

Thanks

H. Hunter Handsfield, MD

21 months ago

You can find answers about the different kinds of HIV test with an easy online search. I would advise that if and when you had particular exposures that concern you, have a lab-based AgAb (4th generation, "duo") test, ideally at 6 weeks after the exposure.If the risk is especially high, you can have both an RNA test at 2 weeks and an AgAb test at 4 weeks. The rapid tests are somewhat less reliable, and you should never have an oral fluids test (Oraquick) which never becomes positive in 2-5% of HIV infected persons.

That concludes this thread. I hope the discussion has been helpful.

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