What is the window period for HIV testing?
Last updated September 3, 2026.
The window period is the gap between exposure and a detectable result, and it runs by test type: a NAT detects HIV 10 to 33 days after exposure, a lab antigen/antibody test 18 to 45 days, a rapid finger-stick antigen/antibody test 18 to 90 days, and antibody tests - including most self-tests - 23 to 90 days, per the CDC. Practical rules: a negative inside the window is not conclusive - retest after the window for your test type closes - and ask which test you are getting, since "an HIV test" spans a 10-day-to-3-month range. Exposure within 72 hours: that is a PEP emergency, not a testing question.
What to do
- Match the test to the timeline. Early: NAT or lab antigen/antibody. Later: any test.
- Retest after early negatives. The window, not the test quality, is the issue.
- Ask which test you received. The name determines when your result is conclusive.
- Under 72 hours: PEP first. Emergency care the same day; testing comes after.
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