Window period - meaning and definition
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Not yet reviewed by a clinician. This health entry was written from the public-health sources listed below and is general information only. It is not medical advice.
Definition
The window period is the time between a possible exposure to an infection and the point when a test can reliably detect it.
At a glance
- The window period is the time between exposure and when a test can reliably detect an infection.
- Every test has its own window period.
- Rapid and self-tests for HIV often have a longer window period than laboratory tests.
- A negative result during the window period may need repeating later.
- Clinic staff can advise when to test based on the date of exposure.
In detail
Every test has its own window period. For modern laboratory HIV tests it is typically around six weeks, and longer for some rapid and self-tests. Tests for chlamydia and gonorrhoea are usually reliable from about two weeks after exposure.
A negative result taken during the window period may need repeating later. Clinic staff can advise when to test based on the date of exposure.
In a sentence
- The clinic told me to come back after the window period for a repeat test.
- The self-test leaflet explained its window period on the first page.
Not to be confused with
- PEP
The 72-hour limit for starting PEP is a different time frame from the testing window period.
Common questions
Why might I need to test again?
If a test is taken during its window period, the infection may not yet be detectable, so a negative result might need repeating later. Clinic staff can advise on timing.
Is the window period the same for every STI?
No. Each infection and each type of test has its own window period. For example, HIV self-tests often have a longer window period than laboratory tests. A sexual health clinic or doctor can advise on your own situation.