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Accuracy of Point of Care HIV Test

Question: 

How accurate is a rapid antibody test at 24 days post exposure? Also, what are the chances of a negative rapid antibody result at 24 days changing at 90 days or 12 weeks assuming no further exposure to HIV.

Answer: 

Hello and thank you for contacting the AIDS Vancouver helpline.

I gather that you are asking about the accuracy and window period of a rapid antibody HIV test.

According to the Canadian AIDS Treatment and Information Exchange: "The window period of the INSTI (rapid) test is estimated to be the same as, or up to one week longer than, the window period for third-generation HIV tests. Third-generation tests can detect HIV infection in 50% of people by 22 days after infection; 95% of people by 40 days after infection; and 99% of people by three months after infection." (1)

Fourth-generation HIV tests and the INSTI rapid test have a sensitivity of about 99.9%. Since the vast majority of people who get tested for HIV are actually HIV negative, the chance of a negative result being false is extremely low.

We recommend retesting at 3 months for a more conclusive result.

Regards, AIDS Vancouver Helpline/Online, Dyson