STD Testing Guide: Which Tests You Need & When

Why Regular STI Testing Matters

Many sexually transmitted infections (STIs) cause no symptoms but can still be transmitted or cause long-term health problems if untreated. Regular testing is a key part of sexual health.

Common STI Tests

Recommended Testing Frequency

What to Expect

• Most tests use a simple blood draw, urine sample, or swab
• Results are typically confidential
• Some clinics offer rapid HIV tests with results in 20 minutes
• Many results take a few days via standard lab processing

Frequently Asked Questions

Window periods, and why testing too early misleads

Every test has a window period: the interval between exposure and when the test can reliably detect infection. Testing inside that window produces a negative result that does not mean what people take it to mean, and this is the single most common reason for false reassurance. Chlamydia and gonorrhoea nucleic acid tests are generally reliable around two weeks after exposure. Fourth-generation HIV tests, which detect both antibody and p24 antigen, are usually conclusive at six weeks. Syphilis serology may take up to twelve weeks. Hepatitis C antibody can take several months.

The practical implication is that a single test soon after a specific risk event is rarely sufficient, and repeat testing at the appropriate interval is standard rather than excessive caution.

Sampling the right site

Urine or a urethral swab does not detect infection at the throat or rectum, and a substantial proportion of chlamydia and gonorrhoea at those sites occurs without symptoms. For anyone who has had oral or anal sex, testing only urine will miss infections that are present. Self-taken swabs are accurate and are routine in many services. Being specific about sites of exposure is not an invitation to judgement; it is what determines whether the testing answers the question.

Notification, treatment and reinfection

• Partner notification is the main reason treated infections do not immediately recur, and services can do this anonymously on your behalf.
• Avoid sex until treatment is complete, including the full course and any specified waiting period, and until partners have been treated.
• Test of cure is not routine for all infections but is recommended for gonorrhoea, in pregnancy, and where symptoms persist.
• Retesting after around three months is advised following chlamydia or gonorrhoea, because reinfection is common and matters more than treatment failure.

Prevention that works alongside testing

Condoms substantially reduce transmission of most sexually transmitted infections, though less completely for those spread by skin contact such as herpes and HPV. Vaccination is available and effective against HPV and hepatitis B, and should be considered regardless of testing history. HIV pre-exposure prophylaxis is highly effective for people at ongoing risk and is accessed through sexual health services, which also provide the regular monitoring that goes with it.