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Accuracy of Antibody test at 4 weeks

I'm a white male with unprotected vag exposure to a CSW in south am. I am not circumsized and have a sensitive glans which was bleeding after exposure of roughly 15min. I was very drunk but she was dry but not sure. I am terrified of the danger I put myself in

I had a dna PCR 2 days after exposure - Negative
I had a rna PCR 12 days after exposure - Negative

I have a litle soar throat and felt like I was about to get sick a couple times over last couple weeks but it could I'm holdin up ok..could be changing weather or stress

my questions are:
1- what is the probability of a false negative from RNA PCR that I took on day 12 (I know it's not an exact science)?

2-how accurate is the ELISA four weeks after exposure? I know 6 weeks to 3 months is recommended but I really need peace of mind as early as possible.

3- do you know of any major testing labs that have the DUO test? I live close to a big city and noone offers it here and my doc never heard of it

4- if I take a Dna pcr and antibody test after the 6 week of exposure, is it concluseve? Also do you recommend I take the test again at 3 and 6 months?

Thanks doc


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300980 tn?1194929400
MEDICAL PROFESSIONAL
Welcome to our Forum.  Your risk of infection from the exposure you mention is not great and the accumulation of evidence you have strongly suggests that you do not have HIV.  As you probably know, being uncircumcised is associated with increased risk of infection, IF EXPOSED, however most CSWs, even in South America, do not have HIV and if when they do, less than 1% of exposures lead to infection. The odds are very much in your favor.  With regard to your specific questions:

1.  As you probably know, in general we do not recommend HIV PCR testing for diagnosis is HIV infection for several reasons.  While the PCR is likely to become positive more quickly than other antibody detection tests (i.e. usual blood tests), at the present time the blood tests are becoming more and more sensitive and detecting infection earlier and earlier so that the time difference in detection between PCR test and antibody detection tests is becoming smaller and smaller and at present is, in general only a week or two.  In addition the time course over which the PCR tests become positive is less well described than for the blood tests and, as a result, it is difficult to make a definitive statement on what a negative PCR test means at any time within a few weeks of exposure to a HIV infected or possibly infected partner.  PCR tests are also more expensive than regular antibody tests.  Finally and most importantly, the false positive rate for PCR tests (i.e. a positive result in persons who do not have HIV) is higher than for blood tests.  Each of this on this Forum have seen a number of people who were worried needlessly because of false positive tests. For all of these reasons, we rarely recommend testing for HIV diagnosis using PCR.  Despite the lack of formal data however, a negative 12 day PCR is strong evidence that you do not have HIV.  

For my interest, can you tell me how much you paid for the PCR testing?  Wondering if the prices have come down from over $100.  

2.  At 4 weeks at least 90% of persons with HIV will have positive tests.  Just as is the case with a DUO (combination HIV p24 antigen/HIV antibody) test, the combination of a negative PCR and a negative antibody test at 4 weeks should be considered definitive evidence that you did not get HIV.

3.  the test is made by Abbott. Doctors may not be aware of it but most labs will know if it.  Your doctor could call their lab.  Perhaps you need to specify the test components rather than calling it a DUO test.

4.  See above.  The combination of a negative PCR and antibody test at 6 weeks would provide definitive information about HIV infection.  there would be no need for further testing.

I hope these comments are helpful to you. The odds are strongly in your favor.  EWH
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Avatar universal
A related discussion, Unprotected vaginal sex with a CSW was started.
Helpful - 0
300980 tn?1194929400
MEDICAL PROFESSIONAL
1.  You do not need further testing.  You do not have HIV.
2.  The azithromcin would kill chlamdia and most gonorrhea but not all.
3.  No
4.  You can get tested for these STDs at any time.  Believe the results.  Talk with your doctor about which tests to have.
5.  I see no reason for you to abstain further

This will end this thread.  EWH
Helpful - 0
Avatar universal
Hello Dr HHH and Dr Hook,
sorry I'm not sure if I exceeded my question limit or you're just buzy but would really appreciate your thoughts, especially in question 1.

Promise i won't keep asking more new questions
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Avatar universal
Hello kind Doctor, I just wanted to follow up with results.
-RNA Pcr 12 days after exposure - NEG
-antibody test 29 days after exposure - NEG
-DNA pcr 29 days after exposure - NEG

what I didn't mention in my original post was j had small red bumps on my glans after exposure that didn't hurt or itch or anything. I took zihromax and tindamax after for preventative measures.

My gc said bumps were seborheic dermatitis but he isn't an expert in stds. I had tissue sample taken 2 weeks after exposure which came back normal. Also had a swab test done for herpes which was also Neg. The bumps have mostly disappeared but I still have one tiny one

1- do I need to take any more HIV tests or can I put this issue behind me?

2- is it safe to rule out gonnorhea and clamidya given my antibiotics?

3- could red bumps be genital warts or herpes?

4- can you kindly recommend which tests I need to take to be totally in the clear of syphillis, herpes, hepatitis and ngu? I don know which tests are conclusive or when is best time to take them (like 6 week or 12 week after exposure).

5- when would you think it's safe to have unprotected sex with my girlfriend (who is totally clean)?

Thanks again for your wonderful insights and guidance. I can't wait to put my nightmares behind me

  
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Avatar universal
Thank you DR Hook
Helpful - 0
300980 tn?1194929400
MEDICAL PROFESSIONAL
Your thalessemia would ot affect your test results.

Please read my comment about the PCR test above.  This is evidence that you do not have HIV but there is no one who knows for sure how strong that evidence .  I wish I could give you firmer information.  

Finally, as I said, your doctor could call his lab and I suspect they can find the DUO test.   EWH
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Avatar universal
Also do you think my pcr result at 12 days would have a high chance of being false negative?
Thanks Dr Hook
Helpful - 0
Avatar universal
Thanks Dr Hook very much

the rna pcr was about $160 (I don't have insurance). Not cheap but I have been so worried about this

DUO - I did specify to my gp (who is young) that I wanted a test that looked for the p24 antigen and he said he didn't know of any. I heard it was approaved for use in usa earlier this summer so perhaps its too new. Im scheduled to take antibody test without pcr a 29 days so I desperatily hope that will be negative.

I dont mean to be greedy with questions but I was born with a blood issue called thalsemia Is there a chance my tests could be inaccurate because of this?

Thanks again Doc


Helpful - 0

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