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What do these HIV PCR quantitative and P24 antigen HIV test reports indicate?

Answered by
Dr.
Dr. S. Murugan

HIV AIDS Specialist

Practicing since :1974

Answered : 2856 Questions

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Posted on Wed, 7 Sep 2016 in General Health
Question: Hi Doctor

Trust you remember me from my earlier question. I have uploaded my test results for PCR RNA, HIV Antigen and HIV Antibody tests amongst others. The tests were undertaken 18 days after exposure.

Could you pls review the same and let me know what is the next suggested course of action, as well as the conclusiveness of these results?
Also, pasting my initial question below for your reference

Recently on a business trip, I went to a massage parlor and got a full body massage. Post the massage, the lady (of unknown HIV status) gave me a handjob and also performed oral sex (while using a condom).

During this time, I also briefly kissed her vagina and performed oral sex on her superficially for 15-20 sex. What are my chances of acquiring HIV? I understand from these forums that Oral Sex has lower but non zero risk of HIV Transmission. Is that an academic thought or have there been reported cases of oral sex leading to HIV transmission.

The incident happened 5 days back and I would like to get a confirmation of my current status. What are the recommended tests which may help me get a confirmation of my hiv status at the earliest?

Specifically, is the PCR RNA test done post 10 days a sufficient test? OR should I now be taking a series of tests to rule out the possibility of HIV.

Appreciate your response
doctor
Answered by Dr. S. Murugan 37 minutes later
Brief Answer:
All test reports are within normal limits.

Detailed Answer:
Hi,
Welcome back.
As per the reports you had sent, you had HIV PCR quantitative test, P24 Antigen test, HIV 1&2 antibody test along with test for Syphilis and routine blood investigations. All are either negative or within normal limits. But regarding the reliability of these tests, I can not say that they are 100% reliable. Each test has its own window period, after which period, we can consider these tests are conclusive. For example, HIV 1and,2 Antibody test will become reliable only after 12 weeks after the exposure. Similarly test for Syphilis will be reliable after 4 weeks following the exposure. So have your tests with the guidance of a physician.
Dr S Murugan
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. S. Murugan 1 hour later
Hi Doctor

Had a few follow on questions as described below

1. What is the window period for PCR RNA Test?
2. How accurate do you think a PCR RNA Test would be at 18 days post exposure?
3. Is it frequent that PCR RNA Test leads to false negatives (gives a negative result even if the user is hiv positive)? Have you observed such cases in your medical career?

Thanks a lot for taking time out.
doctor
Answered by Dr. S. Murugan 49 minutes later
Brief Answer:
False negative with HIV PCR can occur with less than 1 %.

Detailed Answer:
Hi,
Welcome to HCM.
What you had undergone was Quantitative RNA PCR test. It is more valuable as a prognostic test (assess the progress of the disease or the response to treatment or to detect virological failure), whereas Qualitative RNA PCR or DNA PCR or useful in the diagnosis of the disease. HIV PCR and P24 Antigen test can detect the presence of infection as early as a week after the infection had occurred, but can be considered more conclusive by 3-4 weeks after the exposure as in certain cases the detection may likely be delayed.
Quantitative RNA PCR viral load below the minimum detecting level of the test has no value in the diagnosis of HIV.
False negative HIV DNA PCR is less than 1%.
I had not come across with such incidence, but participated in the discussion of such false negative of my colleague's case.
Dr S.Murugan
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. S. Murugan 42 hours later
Hi Doctor

Many thanks for your reply above. Given the nature of my exposure, the time elapsed (25 days today) as well as the test already done, what would you recommend as the best course of action to rule out HIV infection

I could do either a 4th generation P24 antigen and antibody test post 4 weeks (28 days) or a HIV DNA test post 4 weeks. Which of the above would you recommend as being more reliable?


In terms of symptoms, I have a mild fever which is causing this anxiety.
doctor
Answered by Dr. S. Murugan 6 hours later
Brief Answer:
DNA PCR and Qualitative HIV 2 RNA PCR together rule out both HIV 1 and 2.

Detailed Answer:
Hi,
Welcome back.
Antibody test after 4 weeks has no value as the window period for the test is more than 8 weeks.
4th generation test can rule out HIV 1 by 4 weeks after the exposure as the antigen part is very well reliable.
But if you want to rule out both HIV 1 and 2 by 4 weeks, you can take up HIV DNA PCR (HIV 1) or Qualitative RNA PCR for HIV 1 and another separate qualitative PCR for HIV 2 which is available with certain labs. All these test are highly reliable to the extent of 99% or more even on 26th day (for you - tomorrow) after the risk activity.
Dr S.Murugan
Dr S.Murugan
Above answer was peer-reviewed by : Dr. Veerisetty Shyamkumar
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