[Question #7090] Clarification for Community, Part 2

7 months ago
Hey Doctors:Since I have your ear, I wanted to clarify for myself and others what may be confusion regarding the reliability and absolute 100% conclusive nature of Alere Determine 4th generation ag/ab rapid finger prick tests relative to other 4th generation and lab based vein blood draw tests.  In my area, Planned Parenthood and other STD clinics offer this test, and it is fast, convenient and painless.

I have read on this forum about two years ago that Doctor Hook mentioned that not all 4th generation tests have the same dependability, and then found shortly thereafter Doctor HHH saying:

All blood tests, including the rapid fingerstick tests, are equally accurate. The other rapid test, using oral fluids (the Oraquick test) indeed is a little less reliable than the blood tests. But Determine® is equally good as a lab based blood test. You can be 100% confident in your own test results

and

For Alere's Determine test, there was a brief period soon after the test was marketed in which the antigen component of the test was not working well, so that a few infections might have been missed until 6-8 weeks after exposure. However, Alere quickly fixed that problem and currently the test performs like all AgAb tests.

So my question is quite simple: if one takes this Alere Determine 4th generation ag/ab rapid finger prick test at least 45 days past any given exposure, is a negative result 100% conclusive, no ifs, ands or buts about it, crystal clear positively HIV free?  Also, does this negative test mean, absent ever having had HIV or treatment for it, that one was never in their life infected?

There is a lot of information out there saying this test needs 90 days past exposure and not dependable, just wondering if that is wrong and dated?
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
7 months ago
Welcome back and thanks for your offer to provide useful information for other forum users.

You are correct that for a while the Alere Detremine test performed less well than intended, due to prolbems with the p24 antigen component of the test, which was soon corrected. This has been discussed previously. However, you have created an opportunity to summarize (and, I hope, finalize) this issue in a single thread. Here are statements I made in three different threads 2-3 years ago:

No. 2463:  "...recent analysis of the Alere Determine® rapid test suggests that the p24 antigen component of the test is not reliable. In effect, it functions more like a 3rd generation test rather than 4th generation. However, in real world testing this may not make much difference. The third gen tests are virtually 100% reliable 6 or more weeks after the last possible exposure."

No. 3917:  "For Alere's Determine test, there was a brief period soon after the test was marketed in which the antigen component of the test was not working well, so that a few infections might have been missed until 6-8 weeks after exposure. However, Alere quickly fixed that problem and currently the test performs like all AgAb tests."

No. 4207:  "The Alere test is as good as all others, extremely reliable. You are correct that there was a brief time when the antigen component of the test was not working reliably, so the test functioned more like a standalone antibody tests. Mind you, that was excellent, just not quite as good as intended. In any case, the manufacturer corrected the problem and my understanding is that it's working as intended."

Accordingly, your negative result at 45 days is conclusive. Anyone asserting a 90 day requirement for this test is simply wrong. Even before the transient defect was corrected, the test was conclusive by 6-8 weeks.

Thanks again for suggesting clarification of this potentially confusing issue. Also, I hope these comments have settled the issue for you in terms of your own test result.

HHH, MD
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7 months ago
Yes, thank you, it does. 

' Conclusive means you've got your answer, you've proved your theory, and there can't be any doubt about it.'

So, that is good, thank you.

Regarding interpreting results, I had asked 'does this negative test mean, absent ever having had HIV or treatment for it, that one was never in their life infected prior to that 45 days since the exposure and test date at 45 days?  I am sure that is obvious but can you please confirm that as well?

Yes, I also was seeking reassurance, but for future needs and for people here wanting to avoid blood draw from veins, as long as the Alere Determine 4th gen ag/ab test is given in a clinic or clinical setting (such as Planned Parenthood), can you confirm its accuracy is as good as lab done blood draws from veins?

I suppose both answers are obvious, but better to know from the experts than guess?

Many thank you and hope you are doing well in this challenging time we are all living through.


H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
7 months ago
I apologize for the slightly snarky part of my original reply, which you apparently saw before I edited it a few minutes later. Take another look at my reply above.

Once positive, all HIV antibody tests -- and hence all AgAb (4th generation) tests remain positive for life.

Some experts believe lab based tests are inherently more accurate than rapid tests. However, I have seen no data to confirm that belief; the rapid blood tests (but not the oral fluids test) appear to be as accurate as the lab based tests.
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7 months ago
Thank you, and no problem about the comment -- you Doctors provide a service that greatly helps relieve concerns in a safe forum, and I for one appreciate it.

To my idea, one of the great things about this site is the ability to search and browse old questions in order to research and answer many of one's questions without needing to post further.  For me, and for others who might be confused about the many options for HIV testing out there, this post may help some find a reliable and easy path to getting that test done.

As you said in an earlier post:

All blood tests, including the rapid fingerstick tests, are equally accurate. The other rapid test, using oral fluids (the Oraquick test) indeed is a little less reliable than the blood tests. But Determine® is equally good as a lab based blood test. You can be 100% confident in your own test results

Can we conclude that you would not hesitate for a moment to encourage a patient of yours wanting to know their status to pursue this Alere Determine 4th generation rapid finger prick test we are discussing?  And that as long as the 45 day window period or longer is observed a negative result from this test would be final?

I really truly believe this will help people looking to determine their status.   No pun intended.
7 months ago
I meant to say:

Can we conclude that you would not hesitate for a moment to encourage a patient of yours wanting to know their status using this rapid test to pursue the Alere Determine 4th generation rapid finger prick test we are discussing?  And that as long as the 45 day window period or longer is observed a negative result from this test would be final?
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
7 months ago
Yes, I agree with those statements.

That completes the two follow-up exchanges included with each question and so concludes this thread. Please note that repeated questions on the same topic or exposure are strongly discouraged. This being your second linked to the exposure you are concerned about, it will have to be your last. Thanks for your understanding. Best wishes and stay safe.
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