Did HIV Test After An Exposure. Can Any Online Doctor Help Me To Read The Report?

Posted on Sun, 3 Nov 2013

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Sun, 3 Nov 2013 Answered on

Fri, 22 Nov 2013 Last reviewed on

Question : Hi, I had a potential exposure on 13th Oct,13 (Condom broke while having sex with Hi class escort). When I asked her whether there is any concern she said she is not infected with HIV. I am not sure for how long it was broken. My guess would be 2-3 mins. By penis was dry when I pulled it out. I have done following tests on 15th day from exposure with following results: - HIV-DUO (serum) by CMIA (IV th Generation test): NON REACTIVE (0.11) - HIV-p24 antigen detection,serum by ELFA: NEGATIVE - Human Immunodeficiency Virus Type 1 (HIV-1) RNA Qualitative (detection) -COBAS TaqMan: NOT DETECTABLE - HIV-2 RT-PCR, QUALITATIVE: NOT DETECTABLE. My question statistically to what extent these tests combined together is accurate? are these test put together conclusive? What should I do next?

Answered by Dr. Roopa Hiremath (1 hour later)

Brief Answer: HIV testing Detailed Answer: Hi Mr. XXXXX, Thanks for choosing health care magic. I have gone through your query and your episode can be considered as potential exposure. HIV testing depends on the number of days after exposure to HIV. I want to explain few details regarding HIV spread in the body to make you understand the testing better. HIV enters into the body through small abrasions on the genital mucosa during sexual intercourse and reaches the local lymph nodes and multiplies there. It gets spilled back into the blood after 4 -11 days of exposure. So ideally there is no test that can detect HIV within 4 days of exposure. After 4-11 days, HIV can be detected in blood by PCR, p24 antigen can also be detected. These tests are very specific and less chances of showing negative results. After 3 weeks to 12 weeks, the body starts producing antibodies against HIV and these can be detected in serum by ELISA tests. And can be confirmed by western blot assays. Based on the test results you have mentioned in your query, you are HIV negative. A person can be declared HIV negative if two consecutive test results are negative. I suggest a ELISA for HIV 1 and 2 antibodies after 4 weeks from now as confirmation of HIV status as negative. I hope I have cleared your doubts, please let me know if I can assist you further. Thanks.

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

Follow up: Dr. Roopa Hiremath (1 hour later)

Thanks XXXXXXX So can I assume that since p24 as well as PCR RNA test (whose specificity is high as mentioned by you) is negative on 15th day post exposure my chance of becoming HIV positive is also negligible? Is accuracy of all these tests is good on 15th day? Statistically how many people having negative result in these tests became positive later? Though I will definitely take confirmatory test as suggested by you, but I am asking these questions since I am under tremendous mental pressure post that incident. Hope you understand.

Answered by Dr. Roopa Hiremath (2 hours later)

Brief Answer: PCR and P24 useful only in early infection Detailed Answer: Hi Mr. XXXXX, Welcome back. As I have mentioned in my previous reply, PCR and p24 antigen tests are very helpful in early HIV infection. Antibody testing is not usually prescribed during early exposure as there is chances of these tests coming false negative. PCR and p24 antigen tests are not reliable only in infants born to HIV positive mothers and who are breast fed. These babies have maternal antibodies which interfere with the test results. Accuracy of the PCR and P24 antigen tests are almost 100% in first 3 weeks of early infection (21 days) in adults. 3 to 12 weeks after exposure, antibody testing is preferred method. I hope I have cleared your doubts. Thanks.

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

Follow up: Dr. Roopa Hiremath (3 hours later)

Hi I am bit confused. You are saying accuracy of PCR and p24 is almost 100% in first 3 weeks (in my case its weeks) in adults (which I am). But at the same time you are saying antibody testing is preferred method. Thus why p24 and PCR are not preferred method even though its almost 100% accurate? Also since p24 and PCr method are almost are almost 100% accurate on 3 rd week should I consider my results to 100% negative? Or there is any chance of false negative?

Answered by Dr. Roopa Hiremath (17 minutes later)

Brief Answer: HIV antibody testing Detailed Answer: Hi Mr. XXXXX, Welcome back. Please do not get confused. Please read the answers carefully. Antibody testing is preferred method after 3weeks to 12 weeks after exposure, meaning after 21 days to 3 months of exposure. There is very negligible chance of getting false negative by PCR. This can happen when the test is not done correctly meaning technical errors which is very very rare. Hence I have suggested a repeat test of ELISA HIV 1 and 2 antibodies after 4 weeks just to confirm your negative HIV status to relieve your anxiety completely regarding this episode. I hope I have cleared your confusion. Thanks.

Above answer was peer-reviewed by : Dr. Prasad