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Test results conclusive?

Question: 

Hi, I had a high risk exposure with a sex worker more than 3 months back. I got myself tested on the 90th day post exposure using the Chemiluminescence HIV test in a hospital in Mumbai, India. The report gives the following information about the test: -The test was performed on an Immunodiagnostic Vitros ECiQ Analyser and is used for the invitro qualitative detection of antibodies to HIV1 and HIV 2. -The vitros anti-HIV 1+2 assay uses 4 recombinant antigens such as HIV-1 env13, HIV-1 env10, HIV-1 p24 (core) and HIV-2 env AL. -My report reads Non reactive with a reading of 0.05. -The report says anything above 1.00 is considered reactive. The following are my questions: 1) Is the Chemiluminscence HIV test a reliable and an accurate one for HIV testing post 90 days of exposure. 2) I asked the hospital to perform an Elisa test but for some reason they did the Chemiluminscence HIV test despite having an Elisa test available with them. Is there any difference between the two tests and if so which of the one is an accurate one? 3) Do I need any further testing post this after 6 months, the reason being I was diagnosed with kidney stones during the 3 month window period, so was just wondering if that would have any effect on my HIV result. Also I read in many places on the internet that tests are not accurate till 6 months of exposure. 4) Which generation of the test is Chemiluminescence HIV test and what is its window period? Kindly let me know the answers to the above questions, I would be really grateful to you. Many thanks in advance.

Answer: 

 
Hi there!
Thanks for using the AIDS Vancouver Helpline.
First of all, I congratulate you on being tested after a high risk exposure. 
To address your questions;
1) and 4)  Yes, the Chemiluminscence (CMIA) HIV test, also known as the 4th Generation EIA test, is a reliable and an accurate one for HIV testing 90 days post-exposure.
2) The CMIA test is the standard testing method in several countries, including India. 
The difference between the CMIA test and the 3rd Generation ELISA test is that the ELISA test looks for antibodies the body develops in response to an HIV infection. 
The CMIA or 4th Generation EIA test looks for both antibodies and P24 antigens.  The antigen portion of the test is detectable immediately after infection (3-4 days post-exposure) for the first 2-4 weeks.  The antibody portion of the test is detectable from 3-4 weeks onward. Many HIV specialists consider this test conclusive at 6 weeks. However, we recommend being re-tested at 3 months for conclusive results. Both of these tests are considered to have an accuracy rate of 99.9% at 3 months post-exposure.
3) As it is explained on #2, the window period is 3 months/ 12 weeks, so no further test is necessary as long as you have not engaged in high risk activities (unprotected anal or vaginal intercourse or sharing needles).
The production of antibodies does not interfere with kidney storns.
I trust I have answered your questions, however, if you have any further concerns, please feel free to contact us again.
Stay safe and healthy!Jon,AIDS Vancouver Helpline Volunteere: helpline@aidsvancouver.orgp: (Mon-Fri 9-4pm ): (604) 696-4666w: www.aidsvancouver.org/helpline