HIV - International Expert Forum
Question about PCR RNA HIV test
About This Forum:

This forum is for questions and discussions relating to HIV exposure and risks, living with HIV, HIV prevention, HIV testing, HIV transmission, HIV treatment. All questions will be answered by a medical expert from FreedomHealth.

Font Size:
A
A
A
Background:
Blank
Blank
Blank
This expert forum is not accepting new questions. Please post your question in one of our medical support communities.
Blank Blank

Question about PCR RNA HIV test

Dear Dr. Sean,

Hope you are well and thank you for helping all of us here in the forum.

I am in a situation fairly typical of a significant group of posters here. I am a straight male who had a one time unprotected oral and unprotected vaginal sexual encounter with a 22 year old girl from Beijing. Not sure if relevant but she is an educated girl who claimed she only had 2 previous sexual partners.

I had tested myself for HIV and other STDs prior to this encounter and was negative on all counts. After this said encounter, I asked the girl if she had checked herself before and she said she has not.

Exactly 7 days (and 6 hours) after the encounter, I took a PCR RNA HIV test which has a limit of detection (LoD) of 100 IU/ml. I have been reassured by the doctor administrating that test that a result from this test 7 days post encounter is as conclusive as i need to worry myself with. Now I have read countless articles on the Internet since to verify this and cannot seem to reconcile the doctor's advice with what I see in other scholarly articles.

Questions:
1. Isn't the eclipse period for any PCR RNA tests between 7 - 21 days with a median of 10 days?

2. I notice you start testing patients at your clinic with a PCR RNA test 7 days post exposure. What kind of ballpark accuracy (75%? 90% more, less?) would you prescribe to a negative result from such a test?

3. From previous posts you replied to, you seem confident of a negative PCR RNA result post 7 days. This seems contrary to the prescribed eclipse period I read about in (1) and also different from the CDC's recommended 9-11 day wait. Would you mind helping me reconcile this please?

4. For my piece of mind, can you please help me understand the overall risk I am in for HIV, in terms of the patients you see? i.e. how many heterosexual men have contracted HIV from a one off unprotected vaginal exposure?

Thank you very much for your help
1024580_tn?1331577721
hello,
Thank you for your post and welcome to our forum.  I will try to answer each of your questions here below:
1.) That is correct.  However HIV RNA is already detectable at 7 days with a high level of reliability of around 99%.
2.) Our lab gives us figures of an accuracy of 99% at 7 days.
3.) We follow UK guidelines.  At 7 days, it has an estimated reliability of 99%, which increases with time and after 10 days, this would be over 99%.  If we combine this with a relatively low risk sexual encounter like yours, we could consider a negative result to be conclusive.  However current UK guidelines would still recommend a follow-up HIV Duo test affter 4 weeks, even though in practical terms this might not be necessary.
4.) The estimated risk of a heterosexual man having unprotected vaginal intercourse with a known HIV positive woman is less than 1 in 1,000.  If the status of the lady is unknown and this is in the UK, this will be less than 1 in 1 million as there are only about 40,000 women who are positive in this country.
Best wisehs,
Dr José
2 Comments
Blank
Avatar_n_tn
A related discussion, hiv transmisison was started.
Blank
Continue discussion Blank
This Forum's Experts
936016_tn?1332769204
Dr Sean CummingsBlank
FreedomHealth
London,
MedHelp Health Answers
Blank
Weight Tracker
Weight Tracker
Start Tracking Now
RSS Expert Activity
242532_tn?1269553979
Blank
Control Emotional Eating with this ...
Sep 04 by Roger Gould, M.D.Blank
242532_tn?1269553979
Blank
Emotional Eating Control: How to St...
Aug 28 by Roger Gould, M.D.Blank
233488_tn?1310696703
Blank
New Cannabis Article from NORTH Mag...
Jul 20 by John C Hagan III, MD, FACS, FAAOBlank