Understanding testing windows

What a window period is

A window period is the time between a possible exposure and when a test can reliably detect an infection. No test can detect an infection right away. If you test during the window period, the result can be negative even if you have the infection.

HIV window periods

The window period depends on the type of test. A negative result after a recent exposure should be repeated once the window period has passed.

Other STIs

Chlamydia, gonorrhea, and syphilis also take time to show up on tests, and timing varies by infection and test type. Your care team can tell you when to test based on when you were exposed.

• If you test positive for chlamydia or gonorrhea, the CDC recommends retesting about 3 months after treatment, because repeat infections are common.
• Test the body sites that were exposed. A urine test alone can miss throat or rectal infections.
• If you have symptoms, get tested right away. Do not wait for a window period to pass.

If the exposure was recent

If a possible HIV exposure happened in the last 72 hours, contact a provider about PEP right away instead of waiting to test. Starting PEP quickly matters more than getting a test result.