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9th HIV test 136 days after risk exposure.

Question: 

136 days after risk exposure hiv test came negative Is it ok This was the My 9th test for hiv. Previous All come back as negative

Answer: 

Hello and thank you for contacting the AIDS Vancouver Helpline

We understand that you are wondering if you can consider your negative test result at 136 days post exposure to be conclusive. You do not mention what type of HIV test you received and this was your 9th test. Since you don't say what activity you engaged in, we are unable to assess your risk level.

The type of HIV testing you received will depend on where you live. It was very likely one of the following:

EIA (Enzyme Immunoassay) antibody 3rd generation aka ELISA: This test has a window period of 4 weeks to 3 months (although up to 95% of infections are detectable within 4-6 weeks). Most people develop detectable antibodies in 21-25 days. (1)

Fourth Generation EIA test (antigen-antibody combination test or DUO test): Fourth-generation HIV tests can detect HIV infection in 50% of people by 18 days after infection; 95% of people by 34 days after infection; and 99% of people by one and a half months after infection (1). Fourth-generation HIV tests have a sensitivity of about 99.9%. (1)

Rapid test (INSTI test): The window period of the INSTI test is estimated to be the same as, or up to one week longer than, the window period for third-generation HIV tests. (1)

At 136 days post exposure, you are well beyond the window period for all three of these tests, and can therefore consider your result to be conclusive. No further testing is required.

When you engage in an activity that carries a risk for HIV transmission, it is only necessary to be tested once, as long as you wait for the window period to pass. During the window period, you should refrain from engaging in activities that could potentially transmit HIV.

Regards, AIDS Vancouver Helpline/Online, Dyson