When do STIs show in tests?

Clinicians often refer to ‘window periods’ when testing for STIs. This means the length of time it takes from catching an infection to it showing up on a test. The window periods for the tests we use are shown below.

If you think you may have been exposed to an STI we recommend that you test for chlamydia and gonorrhoea 2 weeks after unprotected sex.

For your blood test, we recommend you test 7 weeks after potential exposure (this is the window period for HIV), and then consider testing again 5 weeks later as the window period for syphilis, hepatitis B and hepatitis C* is 12 weeks.

*Hepatitis C can sometimes take up to 6 months to show in a test, so if you are at risk of contracting the virus (through sharing needles or having sex that involves groups of people, chems or fisting), then we suggest you test again 3 months later.

However, if you believe you may have been exposed to HIV in the last 72 hours, we would recommend seeking immediate advice on receiving PEP.

If you order multiple tests within a short period of time we may ask you for more information about why you’d like to retest. One of our clinicians will review your information before we confirm your order. We want to avoid unnecessary testing, so we may check your window period to make sure that the test can be effective.