The short explanation
Different infections take different times to show up on tests. This gap is called the window period. Tests for chlamydia and gonorrhoea are usually reliable from about two weeks after sex. Blood tests for HIV, syphilis and hepatitis B and C can take longer, often several weeks to three months to be fully reliable, depending on the test. So testing one week after sex may miss some infections. Many clinics suggest an initial test around two weeks, followed by repeat blood tests at about six weeks and three months. If you have symptoms, get tested straight away. If the sex was within the last 72 hours and there is a concern about HIV, ask urgently about HIV prevention treatment, called PEP.
What depends on your situation
The parts of this that change from woman to woman. Uncertainty is stated, not hidden.
- Many government hospitals have ICTC centres for confidential HIV testing and STI clinics, often free.
- Using condoms until you and your partner are both tested reduces the risk of passing infections.
- If you might be pregnant, a pregnancy test and emergency contraception discussion may also be needed.
What this answer cannot determine
The boundary of online education. These need a clinician who can see you.
- This answer cannot tell whether you have an infection. Testing at the right times is needed.
Questions for your clinician
Take these with you. You can add any of them to an appointment card.
- Which tests should I have, and when?
- Do I need repeat tests later?
- Am I still within the time for HIV prevention treatment?
- Should my partner be tested too?
When to seek help
Clinician-approved guidance for this topic. When in doubt, being seen is never the wrong choice.
Get help the same day
- Get care the same day if the sex was within the last 72 hours and you are worried about HIV, to discuss PEP.
Book an appointment soon
- See a doctor within a few days if you have sores, discharge, burning when passing urine or pelvic pain.
Raise it at a routine appointment
- Book STI testing about two weeks after the sex, with follow-up blood tests as advised.
Sources
The evidence this explanation is built on.
- Sexually transmitted infections (STIs) World Health Organization
- Sexually transmitted infections MedlinePlus (NIH)
- Chlamydia NHS
Who wrote and reviewed this
Every AskHer answer names its author. A clinically reviewed answer also names the clinician who signed it off — if no clinician is named below, it has not been clinically reviewed.
- Author
- AskHer Editorial (AI-assisted draft) AskHer's editorial team — not an individual clinician Works in English, தமிழ், हिन्दी
- Clinical reviewer
- Nobody yet No clinician has signed this answer off, and no person on the editorial team has read it yet. That is what the “Written with AI assistance” label means. It is queued for an editor to read, and then for a clinician who works in this area. The sources it was drafted against are listed above.
- Review status
- Written with AI assistance — not yet reviewed by a person
- Last reviewed
- Not yet reviewed by a person
- Version
- 1
Correction history
Substantive changes are listed, not quietly edited away.
No corrections have been made since this answer was first published.
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