The information that you posted is incorrect.
1. A conclusive test for OraQuick Advance is 3 months like ALL HIV TESTS.
2. PCR-RNA will not give you a conclusive test result. They are supplemental tests used in conjunction with an antibody test.
Read the OraQuick Package insert. It shows an instance where the test is non-reactive at 112 days and is repeatedly reactive at 121 days.
Are all negatives true negatives?
A Non-Reactive (negative) test means that anti-HIV antibodies were not detected in the specimen. This test result is interpreted as Negative.
It is possible to get a negative screening test if the infection is very recent. This may be because there is a window period of several weeks when a person may be infected but antibodies to the virus have not reached a concentration that is visible. Therefore, if a person has certain risk factors, or thinks they may have been exposed to HIV, they should be retested in three months to be certain of a negative result.
And you're right that an RNA test is not conclusive. I never said it was. I said it is a much more reliable indicator of a person's status after 4 weeks compared to an antibody test.
There are definitely false negatives. But 112 days is beyond the 3 month mark, so the 3 month mark is not conclusive, according to OraQuick data. BTW, OraQuick is reportedly nearly as good as 3rd generation EIAs (lag indicator of ~3 days).
This is what you said,
"If you want more certainty and cannot wait 3-6 months, then you should probably take an RNA test after 4 weeks. It costs $160-$200 out of pocket or via insurance, and you need to go to your doctor. It is a much more reliable indicator on whether or not you are negative."
What I said was more certainty/more reliability. That is different from conclusive.
The CDC currently states that ninety seven percent will develop antibodies in the first 3 months following the time of their infection. In very rare cases, it can take up to 6 months to develop antibodies to HIV. NOWHERE in the guidelines does it say that 3 months is ABSOLUTELY conclusive nor does it say WHAT group of people fall in the other 3% that will take longer than 3 months to seroconvert. So you're wasting your time arguing with people on this forum about what is and isn't conclusive. Time and time again you see people saying "people in chemo and people that are long time IV drug users are the other 3 %" but I guarantee you that you cannot and will not find anything in writing by the CDC that says that.
Please explain and point me to data/studies that suggest that an RNA test is less reliable than an antibody test during the window period. That would help me understand you and the issue better. I may change my mind, or I may not.
My understanding is that if you believe you have ARS, then there should be sufficient quantities of HIV in the blood. An RNA test looks for specific parts of HIV material rather than antibodies that develop after an infection. From the window point of view, copies of HIV RNA can reach high levels (http://en.wikipedia.org/wiki/File:Hiv-timecourse.png). So in this case, I believe a test that looks for HIV material makes more sense than a test that looks for subsequent antibodies.
What you believe and what is fact is two totally different things.
Yes, I mostly agree with you about the time frame when using the commonly used antibody tests, such as OraQuick Advance. My understanding is that these tests are much more sensitive than they were 15 years ago. These tests can detect antibodies on a vast majority of people by 6-8 weeks, which would have not have been detectable using older tests. The OraQuick package insert manual, however, still shows that there are still cases beyond 3 months.
I want to add that HIV testing/treatment R&D definitely progresses, and that newer testing methods (that I've read about) have significantly shortened the 3-6 month waiting time. Abbott, for example, recently got FDA approval for a p24/antibody combo test for earlier detection (~3 weeks, I think). And there are others. Once these become common, I think CDC guidelines may also change to reflect newer technology.
Also, Red Cross uses RNA testing as well as antibody testing to screen its blood donation supply. The RNA testing is used to reduce the window period between infection and antibody testing. The RNA/antibody combo testing gives higher confidence that the supply used for transfusion is HIV negative.
The drawback is the higher cost and wait period when using this combination. Places such as anonymous clinics that use tax funding probably don't have the budget to support this type of testing until the costs go down for free testing. You usually have to go to a doctor to request duo testing and pay out of pocket or bill it to insurance (for the fortunate ones who have insurance or are able to pay--many cannot).
Current methods for the detection of HIV may not detect all infected individuals. An ARCHITECT HIV Ag/Ab Combo test result that is nonreactive does not exclude the possibility of exposure to or infection with HIV-1 and/or HIV-2. Nonreactive results in this assay for individuals with prior exposure to HIV-1 and/or HIV-2 may be due to antigen and antibody levels below the limit of detection of this assay.
The need for a repeat HIV test if still within the window period after a specific exposure should be discussed. Although fourth generation tests shorten the time from exposure to seroconversion a repeat test at three months is still recommended to definitively exclude HIV infection.
From BHIVA pdf recomendations:
The recommended first-line assay is one which tests for HIV antibody AND p24 antigen simultaneously. These are termed fourth generation assays, and have the advantage of reducing the time between infection and testing HIV positive to one month which is one to two weeks earlier than with sensitive third generation (antibody only detection) assays .
This supports that the 4-8 week testing period, using newer p24/antibody tests, does give highly predictable results (for 90+%, vast majority) that should be confirmed after 3-6 months. BHIVA states 3 months for confirmation, as you pointed out.
And more common tests, such as OraQuick Advance, used in the US, show IN ITS OWN DATASET that a 3 month hard line is not always true, and that it does happen to a very small number of people who do test positive.
But like I said before, the hard line 3 month mark depends on several things, such as test sensitivity, antibody production, and (importantly) cutoff confidence. If a confirmation at 3 months means 99.98%, then there is still a 0.02% error. To get to 99.99%, the confirmation period might have to extend to 5 months to cover that additional 0.01%. And the confirmation period might have to extend from 5 months to 6 months to cover an additional 0.005%. So newer tests seem to have shifted the time to test positive window for a vast majority to a shorter period.
It's important to have earlier detection, and that's the way tests are going.
And I want to be clear to say that, from what I have been reading, detection is shifting to earlier with highly predictive confidence. But confirmation testing at a later point in time is just as important, because there's still a small chance that newer testing methods don't pick up everything.
thanks mememe2010947, your comments were stimulating, I appreciate someone who uses common sence and intelect as opposed to just someone who memorizes what the cdc says. I would encourage you to frequent this site often and weigh in.
Yes 6-8 weeks is probably conclusive based on the new tests but until the FDA approves that, we wil never recommend testng before 3 months.
Plz if u can answer my question which I have been searching and not able to find confident Answer.. Are HIV 4th gen antibody test are capable of detecting different antibodies produced by diff HIV stains.. @ 3month mark.. I will b thankful if u can comment on this..
Common antibody tests also list the subtypes being tested, and it looks like most of the major subtypes of HIV-I are covered. For example, OraQuick Advance package insert lists testing for I subtypes A-G, O, and II.
If you're in the Western and Asian countries, the most frequently occurring ones are HIV 1 in the major group, specifically subtypes B, C, F. Common antibody tests are mostly likely checked against these. Check the antibody kit manual if you are concerned about a specific subtype. If you're from Africa or have reason to believe someone else was from Africa, then HIV 2 may be possible. HIV O is an outlier type that's found a lot less commonly from West Africa. Mainly people who are diagnosed with HIV-2 or subtype O in the Western world seem to be direct immigrants or have been in contact with direct immigrants from Africa.
In the future, there will most likely be new subtypes, since the HIV does evolve. Testing technology will probably be updated to reflect that.
If older generation tests check against the most common subtypes, most likely 4th generation tests will cover more than the older ones. For example, with the Abbott test mentioned earlier, the manual lists at least the same subtypes listed in OraQuick Advance. It does seem like common tests are comprehensive.
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Thank for putting some light on it.. well i am from india... The only thing what i know dat i was tested on HIV duo 1&2 4th Gen antibody kit (CMIA) from Dr Lal path lab's.. When i asked them on what kit i was tested they refuse to disclose it. They said its a latest HIV test which is avaliable in market.
Does it matter what test I got? Should I have ask for a specific type of test? I don't even know what kind I had done. Should I find out?
Thanks. But I'm still learning about these issues myself. Reading the posting replies from these experts and health practitioners, studies, CDC, package inserts were very, very helpful in educating me. Many of the questions I had were already answered from this material, and they're mostly consistent across web sites. I took a lot of time to read through them.
My post was only pointing out some inconsistencies in the testing period, and was trying to explain why this was so. I continue to rely on expert (such as Teak) and doctor comments, and official guidelines and publications when I don't understand something. They're very helpful.