Q. Is HIV RNA PCR test conclusive at 12 weeks?

Answered by
Dr. Ravinder Kaur Sachdeva
and medically reviewed by Dr. Vinodhini. J
This is a premium question & answer published on Mar 10, 2020

Hi doctor,

I went for an HIV test at six weeks after low-risk exposure and get false positive. At eight weeks both fourth generation and HIV RNA PCR are negative. At 9 and 10 weeks rapid test is negative. At 12 weeks HIV RNA PCR is negative. Is it conclusive? My doctor told me no need for further tests.

Dr. Ravinder Kaur Sachdeva

HIV/AIDS Specialist


Welcome back to icliniq.com.

To answer your query, I want to give reference of published research that, Although the reported sensitivity and specificity of fourth generation tests are more than 99% in numerous studies, there are several instances of discordance between screening and confirmatory techniques (Liu P et al. AIDS Research and Therapy 2016 13:1).

False positivity can be due to user error or cross contamination, if there is ongoing some other illness eg. malaria, or if there is a history of blood transfusion, autoimmune diseases.

A positive test result always needs to be routinely confirmed using a different type of test or testing kit. Fourth generation tests are more than 95% accurate at six weeks and this needs to be confirmed after three months with a second test.

If the test in your case has been performed at three months after the exposure and is giving negative results, and you have not had another risk, you do not have HIV. Your fourth generation test and RNA PCR at 9 and 10 weeks and further 12 weeks negative RNA PCR, suffices to rule out infection.

If you still have apprehension, get a repeat HIV antibody test at six months of exposure, no need to repeat it in between.

Take precautions in the future (consistent and correct condom usage).

I hope this helps.

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