When do I take my samples, What are the window periods?

Each STI has different window periods i.e. The minimum advisable time between the last sexual contact/exposure and when you take/send us your samples. These window periods ensure that an accurate and reliable result can be achieved. Testing too early after an exposure risks receiving a negative result when you are actually in the early stages of infection. We recommend the following window periods.

  • Chlamydia: from 2 weeks (after last sexual exposure)
  • Gonorrhoea: from 2 weeks
  • HIV: from 4 weeks
  • Syphilis: from 3 months
  • Hepatitis B: from 3 months
  • Hepatitis C: from 3 months

You may wish to test immediately and request another kit later on after the respective window period, but bear in mind you don’t have an unlimited number of kits available to use (personal quota = four kits per year).

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Sexual Health London offers a free STI testing across most of London.
Simply register with SHL.UK and complete an online consultation to order your free STI test kit.