When and how to get tested
Knowing when to test — and which tests to get — is just as important as deciding to get tested. Testing too early can produce a false negative. This guide covers everything you need to know.
Testing windows by infection
Testing before these windows have passed may produce a false negative result. Waiting is not easy, but it produces reliable results.
| Infection | Earliest test | Definitive result |
|---|---|---|
| HIV (4th gen test) | 45 days | 90 days |
| Chlamydia | 2 weeks | 2 weeks |
| Gonorrhoea | 2 weeks | 2 weeks |
| Syphilis | 6 weeks | 12 weeks |
| Herpes (blood test) | 12 weeks | 16 weeks |
| Herpes (swab, during outbreak) | Any time | When symptoms present |
| HPV | N/A — no routine test | Cervical screening only |
| Hepatitis B | 6 weeks | 3 months |
| Hepatitis C | 8–11 weeks | 6 months |
Windows are approximate. Individual circumstances may vary. Consult a healthcare provider if unsure.
Types of STI test
Different infections require different testing methods. A comprehensive screen will use a combination.
Urine samples
Used to test for chlamydia and gonorrhoea in the urethra. Easy to collect at home or in clinic. You should not urinate for at least 1 hour before collecting the sample.
Genital swabs
Self-taken or clinician-taken swabs from the vagina, cervix, urethra, rectum, or throat. Used for chlamydia, gonorrhoea, and herpes. Essential if you have had anal or oral sex.
Blood tests
Used for HIV, syphilis, herpes (IgG), hepatitis B and C. A finger-prick blood sample is sufficient for most home tests. Venous blood is used in clinic for more detailed testing.
Throat swabs
Recommended if you have had oral sex. Pharyngeal gonorrhoea is common in people who have oral sex and rarely causes symptoms. A throat swab is the only reliable way to detect it.
Where to get tested
Sexual health services in the UK are confidential, non-judgmental, and mostly free.
Sexual health clinics (GUM)
The gold standard. Free, confidential, and comprehensive. Staffed by specialists. No GP referral needed. Same-day or walk-in appointments often available.
Find your nearest clinicHome testing kits (NHS)
Free home testing kits are available for chlamydia (under 25s), HIV, and in some areas, a wider panel. Ordered online and posted back for analysis.
Order an NHS home testPrivate home testing kits
Comprehensive panels available online. Tests for HIV, chlamydia, gonorrhoea, syphilis, and more from a single kit. Results typically within 2–5 days.
GP surgery
Your GP can refer you for testing or arrange a basic STI screen. May be less specialist than a GUM clinic but is a valid option, particularly in rural areas.
How often should I get tested?
The right frequency depends on your individual circumstances and sexual activity.
Sexually active and under 25
Annual chlamydia screen at minimum
New sexual partner
Full STI screen after each new partner
Multiple partners
Every 3–6 months (full panel)
Men who have sex with men (MSM)
Every 3 months (HIV, syphilis, gonorrhoea, chlamydia)
After unprotected sex with unknown partner
Full screen at appropriate windows
Before starting a new relationship
Full panel screen recommended
Not sure when to test?
Use our STI Testing Timeline to see when each infection becomes detectable after a potential exposure.
STI Testing Timeline