From the Research
Post-exposure prophylaxis (PEP) does not affect the accuracy of a negative 4th generation HIV test and negative qualitative RNA results at 83 days post-exposure. This combination of test results at 83 days is considered conclusive and indicates you do not have HIV infection, regardless of having taken PEP. PEP typically consists of a 28-day course of antiretroviral medications (such as tenofovir/emtricitabine plus dolutegravir or raltegravir) that work by preventing HIV from establishing infection if taken within 72 hours of exposure. While PEP can delay antibody production slightly, by 83 days both antibody production (detected by 4th generation tests) and viral RNA (detected by RNA tests) would be detectable if infection had occurred. The 4th generation test detects both HIV antibodies and p24 antigen, while RNA testing directly detects viral genetic material. Current medical guidelines consider testing at 12 weeks (84 days) post-exposure to be definitive, and your 83-day testing is essentially equivalent to this standard, as supported by a study published in 2021 1. No further HIV testing related to this exposure is necessary.
Some studies have shown that PEP can be effective in preventing HIV infection, with a low rate of premature treatment interruption and good tolerability, as seen in a study published in 2019 2. Additionally, a study published in 2020 3 found that qualitative viral load testing can shorten the window period for diagnosing HIV in individuals attending for post-exposure prophylaxis. However, the most recent and highest quality study, published in 2021 1, supports the conclusion that PEP does not affect the accuracy of a negative 4th generation HIV test and negative qualitative RNA results at 83 days post-exposure.
Key points to consider:
- PEP is a 28-day course of antiretroviral medications that can prevent HIV from establishing infection if taken within 72 hours of exposure.
- The 4th generation test detects both HIV antibodies and p24 antigen, while RNA testing directly detects viral genetic material.
- Current medical guidelines consider testing at 12 weeks (84 days) post-exposure to be definitive.
- The combination of a negative 4th generation HIV test and negative qualitative RNA results at 83 days post-exposure is considered conclusive and indicates you do not have HIV infection, regardless of having taken PEP.