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Avatar universal

HIV testing in 2013

Up-to-date advice needed. As experts in the UK forum are very inadequate and vague in explaining things.

I understand that RNA HIV tests are used by the blood banks to make sure transfusion transmitted infections do not occur. Does that mean antibody/p24 alone test such as DUO not good enough for Blood banks? which are 'supposedly' - gold standard in 2013 for routine testing, even so that BASHH guidelines recommend it as a 'first line' for diagnostic purposes. I understand PCR RNA HIV test is expensive and takes longer to perform. Blood banks seem to be extremely cautious when it comes to testing blood as they use more than one method.

QUESTIONS

1.Why shouldn't the GUM clinics just follow the same algorithm as the blood banks use for testing blood donor? It would make sense right? I have read that there has never been a single reported case of transfusion transmitted infection since NAAT was introduced and this is simply because RNA HIV test is part of their testing algorithm. If we take the major benefit of RNA PCR shortening the window period to 9 days over antibody/p24 tests. That would leave us just with the way that PCR HIV RNA works. It looks at the genetic material.

My risks were unprotected sex with females when I was young and didn't have a clue about STDs. All this was 10 years ago. I have learned my lesson.

1. I have had about 5 DUO's and 3 INSTI's in the past at correct window period. Results Negative.

2. Would you recommend HIV RNA over INSTI or DUO? (considering my risks were 10 years ago). The reason I am asking because Blood Banks use it, so it must be better than the standard test.

I understand that antibody/p24 are cheap and fast, but thats not the point as a patients perspective. I need to be 100% sure that the test I am taking is spot on. Just like the blood banks ensure safety.

Regards
Ed.
7 Responses
239123 tn?1267651214
MEDICAL PROFESSIONAL
Welcome to the forum.  However, we encourage users to not ask the same question on both this and the international forum.  The answers are always the same on both.  I agree exactly with the replies you had from Dr. Cummings.

1) I cannot vouch for the reasoning of those responsible for UK's GUM clinic policies, but the high performance of the duo test and higher cost of RNA testing presumably are important.

2) The main purpose for RNA testing is to monitor viral load in people with known HIV.  It is not routinely recommended for HIV testing in people at risk or concerned about particular exposures, and I agree with that recommendation.

Nobody with your test results, especially several times and a few years after exposure, ever turned out to actually have HIV.  Do your best to accept the scientific evidence and the reasonsed, science based reassurance you have received repeatedly from several sources.

Regards--  HHH, MD
Avatar universal
Thank you for you quick reply Doctor.

I will try and accept the scientific facts, however I am still lost. If its not routinely offered, why is it used by the blood banks for testing ? I am sure its the same in US. In the UK it is offered by the private clinics for diagnostic purposes to patients at an earlier window period. So the fact is, it is used for diagnostic purposes as well.

Also IF I was infected 10 years ago, would my viral load be high? and would it be appropriate to use RNA test? Incase if antibody/p24 failed to pick it up after all those years.

Would you personally recommend the RNA test or shall I just forget about it? The only thing that makes me go for this test is because blood services use it as part of their algorithm and not a single person got infected that way. I'm not sure if I am making myself clear enough, but I hope you understand what I am trying to say here.

Thank you once again
Avatar universal
Can you please reply to my post. I have only received one reply from your colleague. Thank you very much!!
239123 tn?1267651214
MEDICAL PROFESSIONAL
Dr. Hook will not reply.  We do not comment in each other's threads unless we ask each other to do so.  He and I have been close colleages for more than 3 decades and our opinions and advice virtually never differ.

I cannot speak in detail about blood and tissue bank policies.  But I can imagine some reasons for continued reliance on RNA or DNA testing.  First, they have been doing it for 15-20 years, well before p24 antigen testing became commercially available, and they have systems in place for it; it might be more efficient to continue unchanged.  Second, I believe most blood donation services also use p24 antigen and/or combo (antigen/antibody) testing in addition to RNA/DNA.  Third, RNA/DNA testing actually turns positive a little sooner than p24 antigen, so it's a bit more sensitive in detecting persons with very early HIV testing.  (Imroved sensitivity early obviously is not pertinent to your situation.)  Finally, there may be a political dimension:  the public demand for a totally safe blood supply probably translates into a willingness to spend more money on testing recognized or assumed as the definitive gold standard, even if not actually much better than other tests.

And you are too laser-beam focused on the RNA test anyway.  It is one of the methods behind the success in preventing transfusion-related HIV infections, but it is the combination of testing an donor policies that have driven that success, no single piece on its own.  If DNA/RNA testing were the only method they used, there surely would have been a few HIV infections in recent years from transfusion.

If you had had HIV for 10 years, you probably would be quite ill with overt AIDS and maybe dead by now.  Although it is possible to go that long without symptoms that make HIV/AIDS clinically obvious, it is uncommon.  And yes, your viral load would probably be quite high.

Would I personally recommend RNA testing for you?  Of course not.  And if you came to my clinic and demanded it, we would refuse -- as I suspect (and hope) they have done if you had made such requests at your GUM clinic(s).

So my advice is to accept the scientific evidence and reasoned reassurance you have had (several times) and rely on the standard testing methods, as do almost all persons tested for HIV.  Do your best to stop obsessing about your HIV status, RNA/DNA testing, and (perhaps) an regretted exposure event or a sexual experience from all those years ago.

That will end this thread.  I won't have more to say about it.  Good luck.
239123 tn?1267651214
MEDICAL PROFESSIONAL
And by the way, my opening comment is not an invitation re-post your question yet again in the hope Dr. Hook would respond.  Duplicate questions on the same forum are deleted without reply (and without refund of the posting fee).
239123 tn?1267651214
MEDICAL PROFESSIONAL
As I think about it, probably simple economics supports RNA/DNA testing in blood banks but not persons at high risk of being positive or the clinics they attend, such as GUM clinics.  Blood banks test large numbers of donors who, in general, are at very low risk for HIV.  That allows them to pool specimens  -- they may combine blood from 10, 20, or more donors, then run a single RNA/DNA test.  If the pooled specimen is negative, then  all 10-20 donors are free of HIV.  If positive, they then test each specimen individually.  Since there are so few positives, at the end of the month they might have tested 1000 people by doing only 50-100 tests.

By contrast, most patients at risk are tested individually, and pooled testing makes little economic sense when testing a relatively high risk population, as in a GUM clinic.
Avatar universal
Thank you for your time and input. Very informative and it makes sense. I feel re-assured.

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