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Dr. Andrew Rynne
Dr. Andrew Rynne

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Is HIV RNA test done post 20 days of exposure conclusive?

Answered by
Dr. S. Murugan

HIV AIDS Specialist

Practicing since :1974

Answered : 2843 Questions

Posted on Mon, 29 Aug 2016 in HIV and AIDS
Question: HIV RNA - Undetected
HIV Ag/Ab EIA - Nonreactive

The blood was drawn 20 days post possible exposure. Are these results conclusive or do I need to be retested? The clinicians at the facility told me the tests were final and theres no need for another retest but I would like a professional opinion as well.
Answered by Dr. S. Murugan 2 hours later
Brief Answer:
You are almost free from HIV 1 infection as per your test reports.

Detailed Answer:
Welcome to HCM.
Thanks for posting your query.
HIV RNA PCR can detect the presence of the infection (if any) as early as 7 days after the exposure, but it will be considered as more conclusive 3-4 weeks after the exposure. Your test report is almost conclusive.
Regarding HIV Ag/Ab EIA test, it has two components.
1.Antigen detection_ that will be considered conclusive by 3 weeks. But it can detect only HIV 1 and not HIV 2.
2. Antibody detection part of the test which can detect both HIV 1 and 2, but will be reliable after the window period (6-8 weeks , up to 12 weeks).
Qualitative RNA PCR also can detect only HIV 1 and not HIV 2 unless you had two separate test (another one specific to detect HIV 2).
HIV 1 is 99.9% common throughout the world except certain pockets of XXXXXXX HIV 2 prevalence is less than 0.5%.
Dr S.Murugan
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
Follow up: Dr. S. Murugan 16 minutes later
Hello Dr.

Thanks for your reply. Today I took a 4th generation Ag/Ab test. It is just over 7 weeks post possible exposure, will this final result be 100% conclusive? My possible exposure was protected vaginal sex with a commercial sex worker in the United States. I'm almost 100% sure the condom remained on and intact the entire time. I just wanted to test just to be safe. Can I rely on my negative results? I know you said they are not 100% conclusive, but are they at least close? Can I expect a negative result on this next test?
Answered by Dr. S. Murugan 58 minutes later
Brief Answer:
You are free from HIV 1 infection beyond any doubt.

Detailed Answer:
Welcome back.
You had protected intercourse. That itself assured you that the possibility of HIV is almost nil. Regarding the negative 4th generation test 7 weeks after the exposure ruled out the possibility of HIV 1 infection to the extent of 100%.
Possibility of HIV 2 infection is almost nil with the protected exposure. So you need no further test for HIV.
Dr S Murugan

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

The User accepted the expert's answer

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