References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Knowing when to get tested for STIs matters because different infections have different window periods. Test too early and you might miss an infection. Test at the right time and you can be confident in the result. Here’s a clear guide to when testing makes sense.
Order a discreet home STI test
Reasons to Get Tested
- You have symptoms (discharge, pain, sores)
- You’ve had a new sexual partner
- You had unprotected sex
- A partner has tested positive
- You’re starting a new relationship
- You’re planning pregnancy
- Annual routine screening
- You’re starting or continuing PrEP
Timing After Exposure
| Situation | When to Test |
|---|---|
| Within 72 hours of high-risk HIV exposure | Contact clinic about PEP immediately |
| 1-2 weeks post-exposure | Chlamydia, gonorrhoea, trichomoniasis |
| 4 weeks post-exposure | HIV (4th-generation test) |
| 6 weeks post-exposure | Syphilis reliable |
| 3 months post-exposure | All tests definitive |
Regular Screening Frequency
- Under 25, sexually active — at least yearly for chlamydia
- New partner — after each new partner
- Multiple partners — every 3-6 months
- MSM at higher risk — every 3 months
- On PrEP — every 3 months as part of follow-up
If You Have Symptoms
Don’t wait for a specific timeframe. Symptoms warrant same-day or same-week testing:
- Unusual discharge
- Burning on urination
- Genital sores or blisters
- Pelvic or testicular pain
- Unusual bleeding
- Rashes or lumps
After a Known Exposure
If a partner tests positive or you’ve had a specific risky exposure:
- Within 72 hours — consider PEP if HIV risk
- 1-2 weeks — first round of testing
- 4-6 weeks — HIV and syphilis
- 3 months — final confirmatory tests
Routine vs Urgent Testing
- Routine — annual screening, no specific concern
- After new partner — important but not urgent
- After symptoms — prompt testing recommended
- After high-risk exposure — urgent for PEP decisions
Don’t Delay
Early testing and treatment reduce complications. Even if the test shows you’re fine, the peace of mind is worth the effort.
Read more: When to test | STI incubation periods | Testing frequency
Frequently Asked Questions
Can I test the next day after sex?
Most STI tests are too early to detect infection the day after sex. Wait 1-2 weeks for chlamydia and gonorrhoea.
How often should I test in a monogamous relationship?
Annually is usually enough, or as clinically recommended.
Should I test just because I’m worried?
Yes. Testing for peace of mind is a valid reason.
Related reading
- How Accurate Are Rapid HIV Tests?
- Anonymous STI Testing: What It Means
- Are HIV Tests Accurate If You're on PrEP, PEP or ART?
- Are STI Blood Tests Accurate?
- Before You Get Intimate: Why You Should Ask About STI Testing
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
