[Question #11452] A simple question for you're expertise with regards to testing.
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14 months ago
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Hi Doctors hi hope you're keeping well. Right all this is is a simple question regarding tests. I am not looking to talk about symptoms or exposures or anything else other than to be educated on tests & how they work. Right i was lead to believe a pcr RNA hiv test is an early detection test Valid from 4 days to 4 weeks & after 3 months that test basically becomes invalid & inaccurate. But out of interest i was looking at tests the other day & was slightly confused. I seen an RNA Quantative test AND also an RNA Qualitative test, both were rapid tests & for hiv 1. My simple question is how do these tests differ & what are the window periods/ how long are these tests valid for? I have also heard of a hiv 1 proviral DNA test & from what i understand this is a more thorough test & mainly used for hiv patients to view the amount of virus in there body to see how well there medication is suppressing the virus, it can also be used as a diagnostic tool also but not near as frequent as the routine 4th gen test. If you could break this down for me clearly so i understand i would be greatly appreciative.
Thank you in advance take care.
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Edward W. Hook M.D.
14 months ago
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welcome back to the Forum. I'm disappointed that you continue to search the internet regarding HIV. It has misled you before and appears to have provided incorrect information to you which has led you to return to the Forum. As I said 2 months ago- "searching the Internet, as you obviously do, is a bad idea. Not all of the scientific literature is high-quality and not all statements found on the Internet represent scientific investigation at all. Much of what is said there is taken out of context, out of date, or simply wrong. Over and over we have found that the Internet is far, far more likely to this lead our clients astray than to be of any help. I believe you fall into that category."
With that prelude, let me address your questions. There are 3 major types of tests for HIV- tests for HIV antibodies which require the time needed to develop antibodies to become positive and which take 8 weeks to provide conclusive results, test for HIV antigens (the protein coat of the virus) which, because they do not need to wait for antibodies to be produced, are conclusive sooner, at 6 weeks after and exposure, and the ultra sensitive HIV RNA PCR tests which provide conclusive results any time more than 11-12 days after an exposure. HIV RNA PCR tests are used both for diagnosis (the qualitative test) and for evaluating response to therapy in persons on therapy for HIV. In persons with HIV, once a test is positive, they remain positive unless they are receiving therapy for HIV.
I hope these FACTS are helpful. Please stay off the internet. EWH
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14 months ago
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Thank you very much for your response. Ok then so let me get this absolutely crystal clear without doubt. A
10 day HIV RNA PCR test ( which can also be referred to an an early detection rapid test) from a blood draw from a vein sent to a lab is reliable for diagnosing HIV even over a year has past from the initial infection is that correct? I know as you say there's an awful lot of conflicting info all over the net not only to do with hiv but stuff in general. As i said above there is a laboratory in London in Harley Street ( famous for clinics & medical services) & on there website like i said they had a RNA Quantative AND a RNA Qualitative which somewhat confused me because i was only lead to believe that there was only one pcr RNA HIV test & that was specific for diagnosing very early hiv infections then becomes obsolete & not accurate after the 3 month mark. Then obviously you have the proviral DNA test which is a different test.
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14 months ago
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Let me ask this also. If a person has hiv & is on ART.. will a 4th generation hiv test still flag up positive? Because of the the antibodies/antigen that remain in the body?
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Edward W. Hook M.D.
14 months ago
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As I said above the Internet has misinformed you. HIVRNAPCR test can be configured to be qualitative, giving yes, no answers or quantitative to provide the copy number of viruses present. The latter test takes extra steps and is used for an evaluating person who are on therapy. Successful therapy reduces the level of HIVRNA undetectable in the PCR test
In person who have not received HIV therapy and HIVRNAPCR test will reliably diagnose the presence of infection anytime more than 11, not 10, days following acquisition of infection. The idea that an untreated persons and HIVRNAPCR test is no longer reliable after three months is either a misinterpretation on your part or another example of Internet based misinformation.
Persons who have HIV, even if on effective therapy, will still have reactive fourth generation tests for HIV because they will still have antibodies to the virus. EWH.
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14 months ago
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Right that's easy to understand the prc rna qualitative 11 day onward test is a simple yes or no test ( meaning you either have the virus or dont) & it is valid & accurate basically indefinitely so long the person is not on ART.
The quantative rna test actually is used for people that have been diagnosed with the virus & is utilised to measure the amount of virus in their body and to see how well there meds are surpressing it. I take it they dont don't use the quantative rna test for diagnostics as they ( the drs) rely on the qualitative rna test for that then if positive move to the quantitative rna test. Tell me last question where dose the proviral DNA test fit in with all this testing what circumstances would that be used for. Thanks for the information anyway as always thanks.
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Edward W. Hook M.D.
14 months ago
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Final answer. When HIV infects a cell the HIV RNA causes the cell to make a DNA copy of itself. Thus detection of HIV RNA and HIV pro-vial DNA are roughly equivalent as diagnostic tests.
This completes this thread. EWH
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