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4th Generation Antigens/Antibody Test at 9 Days Post Exposure


I had the 4th generation test exactly 9 days post exposure. I had the test after symptoms started. Fatigue, other flu symptoms, 99.6 fever. I’ve read that the antigens part of the test is effective at 10-14 days post exposure. My test was negative, but I don’t know if it means anything. Will the 4th generation test detect antigens at 9 days if there are symptoms? I went to my regular doctor and had blood drawn for the RNA/viral load test yesterday, but it will probably be next Friday when I get the results. I’m still having the symptoms. This is the 7th day. My exposure was unprotected oral and protected anal (both receiving). Thank you for answering my questions.



Thank you for your inquiry. From what we gather from the question, you were asking about the accuracy of a 4th generation test 9 days after engaging in unprotected oral and protected anal sex. From the information given, this scenario is determined to be Low Risk (evidence of transmission occurs through these activities when certain conditions are met).

The scenario mentioned above could meet the three components of the Transmission Equation if the condom was not used properly or broke during anal sex. It was very responsible of you to access testing after engaging in a risky activity. The 4th generation test may detect antigen 9 days post-exposure, but the results would not be 100% reliable, making re-testing absolutely necessary. The RNA/viral load test conducted after the 4th generation test (can detect HIV infection as early as 1-2 weeks post-exposure) will be a good indicator of your HIV status (1). In the case of a negative result, further testing 6 weeks and 3 months post-exposure is recommended for completely conclusive results. If you are continuously engaging in higher risk activities there are biomedical approaches such as PrEP and PEP that help lower your risk of acquiring HIV. Refer to your physicians for further information.

Although worrisome, your symptoms may be due to a variety of other stressors on your body. Anxiety about suspicious symptoms may increase the stress your body is going through, and ultimately make you feel worse.

Recommendation: Refer to a health care provider for HIV testing outside of the window period.


AIDS Vancouver Helpline/Online, Marie