When should I get tested for HIV?

I had unprotected sex once with a new or unknown partner

What to do: Plan to test for HIV. The right timing depends on how long ago the exposure was.

• Less than 21 days ago: A self-test won't yet give a reliable result. If you want earlier detection, lab-based 4th-generation tests can detect HIV from around 18 days after exposure¹. Otherwise, wait and retest at 21 days.
• 21 days to 12 weeks: An INSTI self-test can detect HIV during this window for most people. A non-reactive result should be confirmed at 12 weeks.
• 12 weeks or more: A self-test result is considered conclusive at this point³.

What else: Consider testing for other STIs at the same time. STIs like chlamydia, gonorrhoea and syphilis are more common than HIV and can be missed if you only test for HIV.

Read more about the HIV window period →

I have unprotected sex regularly or have multiple partners

You're in a higher-risk group, and routine testing is recommended. The CDC, BHIVA and WHO recommend testing every 3 to 6 months for sexually active adults in this group, regardless of symptoms¹²³.

What else to consider:

• PrEP (pre-exposure prophylaxis): a daily medication that reduces the risk of HIV infection from sex by about 99% when taken consistently. Available through sexual health clinics and some online services.
• Routine STI testing: STIs are common in people with multiple partners and most have no symptoms. Regular comprehensive STI screening is the standard recommendation.

Modern self-tests show 100% sensitivity and 99.8% specificity in untrained user studies⁵ — comparable to rapid tests used in clinics.

I have flu-like symptoms after a possible exposure

Symptoms 2 to 4 weeks after exposure can sometimes be early signs of HIV — fever, sore throat, swollen lymph nodes, rash, fatigue. But: most flu-like illnesses are not HIV, and the symptoms HIV does cause overlap with many common conditions.

What to do depends on how long ago the exposure was:

• Less than 21 days: An antibody self-test is unlikely to give a reliable result yet. If you're concerned, speak to a doctor or clinic about earlier-detection lab tests.
• 21 days or more: Test now. A reactive result needs laboratory confirmation; a non-reactive result should be retested at 12 weeks.

HIV symptoms guide →

My possible exposure was within the last 72 hours

This is urgent. Post-exposure prophylaxis (PEP) is a 28-day course of medication that can substantially reduce the risk of HIV infection — but it must be started within 72 hours of exposure, and the sooner the better¹.

Where to access PEP:

• Sexual health (GUM) clinics — typically able to start PEP same day.
• A&E or emergency departments — out of hours, weekends.
• Some GP services — though referral is sometimes needed.

PEP is not a substitute for testing. After completing the 28-day course, you'll still need to test at 12 weeks after your last dose³.

HIV window period →

I'm pregnant or planning pregnancy

HIV testing is part of standard prenatal care across most of Europe⁴. Every pregnant person is offered an HIV test as part of routine antenatal screening — typically in the first trimester.

Why it matters: if you have HIV, treatment during pregnancy can prevent transmission to your baby almost completely. Without treatment, the risk of mother-to-baby transmission is around 25%; with effective treatment during pregnancy and delivery, that risk drops to less than 1%¹.

If you're planning pregnancy and haven't tested recently, now is a good time. Speak to your GP, midwife or sexual health clinic.

I want to test as part of routine sexual health

A self-test gives you a private, accurate result at home. You don't need a specific exposure or reason to take a self-test — many people use it as part of regular sexual health awareness.

The CDC recommends every adult be tested for HIV at least once as part of routine healthcare¹. Sexually active adults benefit from testing more frequently, depending on individual circumstances.

If you've never tested before, the easiest first step is to test now. Whatever the result, you have a clear next step.

My partner just tested positive for HIV

First: their result needs laboratory confirmation if it was a self-test. Once confirmed, they should start antiretroviral therapy (ART) as soon as possible. Modern ART is highly effective, and people on treatment with an undetectable viral load cannot transmit HIV to sexual partners (Undetectable = Untransmittable, U=U)⁶.

For you: get tested. The window period applies — test 21 days after your most recent sexual contact for a screening result, and 12 weeks for a definitive result.

If your most recent contact was within the last 72 hours, contact a clinic about PEP urgently — see Scenario 4 above.

Going forward: PrEP (pre-exposure prophylaxis) may be appropriate for you. If your partner starts effective treatment and reaches an undetectable viral load, U=U applies and onward sexual transmission is prevented.

Living with HIV — what to expect →