Why do you tell some people 3 months and others 6?


I was reading through archives, and I notice that you infrom people that 3 month tests are conclusive and others to wait 6 months. Why is that and what's the difference? Just curious.

Would you ever tell someone to test after 6 months or is that the maximum time to wait for a conclusive test? Thank you doctor. Donation on its way!!



This question comes up frequently. In fact it qualifies for QTND (question that never dies) status. See below.

A negative six-month FDA-approved anti-HIV test would be considered conclusive.

Thanks for your donation to the Robert James Frascino AIDS Foundation (www.concertedeffort.org).

Be well. Stay well. Noel!

Dr. Bob

confused,pls enlighten! (3 MONTHS VERSUS 6 MONTHS) Apr 20, 2008

Hi Studly(ok Dr.Studly.) I tested negative at 2,3,4,9 and 13 weeks for unprotected vaginal sex with a co-worker. She stated she is negative. I don't know for sure as I never saw the paperwork,know she slept with at least one guy during the time we had sex and no longer work at the same place as her. Is this conclusive? I had read you stated to an hiv pos woman that her man should follow up his 3 month test with a 6 month test. I don't understand. Do I need to test to 6 months?(I thought I was in the clear and done with testing.) Thanx Dr.Stud!

Response from Dr. Frascino


"Dr. Stud"? Oh I bet you say that to all the cyber-sexperts you are trying to get information out of, right? Well, as you can see, your tactics work quite well!

A negative test at the three-month mark is generally considered to be definitive, unless there are extenuating circumstances. (See below.)

Oh and by the way, WOO-HOO!

Dr. Bob

Where is the line??? (interesting question...) (3 MONTHS VERSUS 6 MONTHS) Nov 7, 2007

Hello Bob, and thank you for all the big effort you make here every day. You really helped me and many others. I'm sorry for my bad English, as you see you are international :)

My question is the following: after a single exposure (condom broken) three months ago, now I have taken the "definitive" test 12 weeks later, and it is negative. I also took some other tests before this 12 weeks and a half (almost 13 weeks), but as I have read, these negatives can't be considered conclusive.

Can I consider this 12-weeks negative Duo Test conclusive? I hope so...but the following question would be: where is the limit?where is the line? I mean, after reading a lot and learning, many people say that I should even wait until the 6 month mark. What is the reliability after 12 1/2 weeks? Are there documented cases where after a 3month negative, somebody became positive?

Thank you for your patience and dedication, a donation will be made.

Response from Dr. Frascino


In general I consider a three-month negative FDA-approved screening HIV-antibody test to be definitive, unless there are extenuating circumstances. I have covered this topic extensively in the archives. Have a look. There is no "line" per say. The immune system doesn't really work that way. The vast majority of HIV-positive folks will have detectable levels of anti-HIV antibody in their blood by four to six weeks. The three-month mark is set to catch those who may take a bit longer to develop a detectable immune response. Extremely rare cases of delayed seroconversion have been reported. If you are worried, the option to get a six-month test is always open to you. In your specific situation, I personally do not feel it is necessary.

I'll reprint some information below from the archives.

Dr. Bob

Again with the 3/6 Months Dec 15, 2006

Dr. Bob -

I have found that although I tested negative at the 3-month mark, my anxiety is creeping back. Part of that for me is the on-and-off diarrhea that I am experiencing; my other "symptoms" have all resolved.

So, I just read your response to the guy who had 4 unprotected encounters and your wishing him well at his 6-month test; this was the first I've ever heard you put so much emphasis on the 6-month follow-up.

My activity was low- risk (receptive oral/no ejac. and frottage), but I'm thinkin', "Hey, Dr. Bob's backing off on his 3-month woo-hoos." It seems to me that either the 3-month test is conclusive or it's not, regardless of the activity that preceded it. Participating in risky activity should not affect whether one is a late seroconverter or not. Reminds me of the term "fuzzy math."

Freaking again,


Response from Dr. Frascino

Hello Freaking-Again Mike,

My opinion on testing has not changed, nor is it as black and white as you might have imagined. I'll repost a question from the archives that's several years old that hopefully will clear up any confusion and show you my opinion really hasn't changed.

Regarding your situation, I would consider your negative three-month test definitive and conclusive, OK?

Stop worrying. Return to WOO-HOOing.

Happy Holidays.

Dr. Bob

Window Period Sep 6, 2006

Dear Dr. Frascino: I just recently made a contribution to your foundation. The only reason I mention it, is to encourage others to do so. Your work on this site and elsewhere is greatly appreciated and should be recognized.

My question is regarding window periods. I had an incident in April that put me at risk for HIV (relatively low). I was tested at three weeks, six weeks, and again after 16 weeks. Why is it that some people reccommend a definitive test after three months and others suggest that you need to wait for six months. Is my test at 4 months conclusive or should I go again at six months.

Also, what is the difference between the blood tests I got the first two times from my doctor, and the oral test I received at a clinic after 16 weeks (I couldn't wait for the blood test to come back, the 20 minute window helped my peace of mind).

Thank you!

Response from Dr. Frascino


Thanks for your donation! (www.concertedeffort.org)

The three-month versus six-month question is definitely a QTND (question that never dies). I have tried to explain this conundrum many times in the past; however, I do realize it continues to be a source of confusion and worry for folks. I'll reprint just one of my attempts at explaining the rationale for the three-month window period below. If you're an avid forum reader, you might have noticed the current controversy has now been focusing on six weeks versus three months! You can catch up on that discussion in the archives, if you're interested.

Regarding the differences between tests, again this has been addressed many times in the archives. Have a look. The FDA-approved rapid tests are both accurate and reliable. We use them at the Frascino Medical Group (650-917-1357) on a daily basis.

Congratulations on your negative 16-week test. It is definitive, conclusive and WOO-HOO-able.

Stay well.

Dr. Bob

Robert James, this is your Mother talking Jul 26, 2004 okay so I am not your mother, but I do need some advice. You have said over and over if you think you were exposed test at 3 months, but you also say if you know you were exposed test to 6 months??? What gives? Don't quote the CDC. I want you to be straight with me, (there is a joke in there) Why are you not consistent? 3 months if I think and 6 months if I know! What is your opinion? I have had the works when it comes to symptoms and was diagnosed for 1 STD, all are gone except for the PN. This after a 1 time insertive exposure with a female who I fear has HIV. I had a neg elisa at 5 months. Do I need another test or not? And why the 3 or 6 months answers? P.S. and don't be straight the world loves you the way you are!

Response from Dr. Frascino

Hello Not My Mother, I do realize this issue is more than a bit confusing, so let me try once again to explain the rationale behind our advice. The question seems simple enough: three months or six months for a definitive result. The answer, however, is far from "straight" forward. The confusion results from variability in the immune response (time to produce anti-HIV antibodies) which is different from person to person, limitations in the test's sensitivity and specificity (ability of the test to pick up all true positives or eliminate all true negatives), and clinical judgment. In addition, there are special circumstances where our general recommendations for testing might not be applicable. For instance, when folks are simultaneous exposed to hepatitis C and HIV or when folks have previously received experimental HIV vaccines, consultation with an HIV specialist is often required to provide guidance on when to test and how to interpret the test results. Added to his are many very anxious folks who are absolutely certain they have contracted HIV, but in reality, have no identifiable risk. You know the type: "Grandma farted while trying to get out of her Barco-lounger chair. It smelled worse than usual. Now I'm convinced I've got AIDS." Of course, these folks require basic HIV prevention counseling and education, not HIV testing. But that doesn't stop them from getting tested "just to be sure," etc. So what would the answer be to these folks' "three months versus six months" question? In reality, neither, since they didn't need testing in the first place. And what about folks with some degree of potential ongoing exposure? How do we monitor their HIV status? So you can see this is not as straight forward as you might originally think. OK, back to your questions. The best I can do is take all the information provided to me from an individual questioner, apply the information concerning the limitations of HIV testing, the results of large-scale epidemiological studies, and the scientific facts pertaining to how HIV is transmitted, and then give the questioner my expert opinion and advice. Whether that person chooses to accept my advice or follow my recommendations is, of course, totally up to him or her. The reason I quote the CDC's published guidelines is that they are perhaps the most conservative set of published and well-referenced recommendations I have seen. So what can I, in good conscience and backed by science, advise? I can say that following a single possible or known exposure, the vast majority of infected persons will develop detectable HIV antibodies within three months of exposure. If the initial negative HIV test was performed within the first three months after exposure, repeat testing should be done at three or more months to rule out the possibility of a false-negative result within the window period. If the ELISA test is negative at three months or more after an exposure, the individual is extremely likely to be HIV negative. This is all based on statistical risk analysis and large-scale epidemiological studies. Now comes the confusing part. If a person was significantly exposed to a known HIV-infected person, the estimated statistical risks change and a second repeat test "might" be considered at six months or more from the exposure depending on the circumstances. And yes, there are very rare reports of seroconversion 6-12 months after a known exposure. The exact details of these very rare historical cases are a bit sketchy, but the reports do indeed exist in the medical literature. Today, however, extended follow-up testing beyond six months after exposure to rule out the extremely rare possibility of delayed seroconversion is not recommended, except under exceedingly rare circumstances that should be based on the clinical judgment of an HIV specialist. I realize some folks may find this response unsatisfying and perhaps unsettling. However, I'm here to provide you with the best confirmed scientific knowledge that we have, and that's the extent of our knowledge at this time. I'm also here to provide you with an expert opinion about that science. So let's proceed "straight ahead" (or should that be "gaily forward?") to your question. I would consider a negative ELISA test at five months following a "1 time insertive exposure with a female" of unknown HIV status to be definitive. I would not recommend additional testing. However, as always, the choice to follow my advice or not is totally up to you, whether you are my mother or not.

Good luck.

Dr. Bob