What should I do if I have non-reactive HIV (Human Immunodeficiency Virus) test results at 63 and 91 days post high-risk exposure?

HIV Testing at 63 and 91 Days Post-Exposure: Final Testing Recommendation

You should obtain one final HIV test at 12 weeks (84 days) post-exposure using both a laboratory-based antigen/antibody (Ag/Ab) test AND a nucleic acid test (NAT) to definitively rule out HIV infection. 1, 2

Why Additional Testing is Needed

Your negative tests at 63 days (9 weeks) and 91 days (13 weeks) are highly reassuring, but the 2025 CDC guidelines specifically recommend definitive testing at 12 weeks (84 days) post-exposure with both laboratory Ag/Ab testing and NAT to account for antiretroviral medication washout periods and test window periods. 1, 2

Key Considerations for Your Situation

If you took post-exposure prophylaxis (PEP):

• Antiretroviral medications can suppress HIV viral load, delay antibody formation (seroconversion), and reduce the ability to detect HIV infection. 1
• The 12-week timepoint is specifically chosen based on data about antiretroviral washout timelines and HIV test window periods. 1
• Your test at 91 days is very close to the recommended 12-week mark, but the guidelines emphasize both Ag/Ab testing AND NAT at this specific timepoint for definitive exclusion. 1, 2

If you did NOT take PEP:

• Fourth-generation Ag/Ab tests are considered conclusive after 12 weeks of potential exposure. 2
• Your 91-day test is past the 12-week mark, which is highly reassuring, but combining it with NAT provides the highest sensitivity for detection. 1, 2

Testing Protocol for Final Confirmation

Obtain at 12 weeks (84 days) post-exposure:

• Laboratory-based fourth-generation antigen/antibody test (NOT a rapid oral test) 1, 2
• Diagnostic nucleic acid test (NAT/HIV RNA test) 1, 2

Important testing caveats:

• Do NOT use oral fluid-based rapid HIV tests, as they are less sensitive for detecting acute or recent infection than blood tests. 1
• If NAT is unavailable at your testing site, the laboratory-based Ag/Ab test alone at 12 weeks should detect the vast majority of infections when accounting for antiretroviral washout, though NAT is strongly preferred for optimal sensitivity. 2

What Your Current Results Mean

Your non-reactive results at 63 and 91 days post-exposure indicate:

• Extremely low probability of HIV infection 1, 2
• However, a negative test result does not completely rule out HIV infection if taken during the window period or if antiretrovirals from PEP suppressed detection. 1
• The final 12-week test with both Ag/Ab and NAT is designed to definitively exclude HIV infection accounting for all potential delays in detection. 1, 2

After Final Testing

If your 12-week test is negative:

• No further HIV testing related to this exposure is needed. 1
• Extended follow-up to 12 months is only recommended in specific circumstances, such as if you became infected with hepatitis C (HCV) following exposure to a source coinfected with HIV and HCV. 1

If you develop symptoms compatible with acute retroviral syndrome:

• HIV testing should be performed immediately regardless of the interval since exposure or previous negative test results. 1
• Acute HIV symptoms include fever, rash, lymphadenopathy, pharyngitis, and myalgias occurring 2-4 weeks after exposure. 1

Critical Pitfall to Avoid

The most common error is relying solely on antibody-only tests or oral rapid tests during the post-exposure period, which have lower sensitivity for acute infection and can be further delayed by antiretroviral medications. 1, 2 Always use laboratory-based fourth-generation Ag/Ab testing combined with NAT for definitive exclusion at 12 weeks. 1, 2