Sexually transmitted infections (STI) tests

If you or your sexual partner has unprotected sex with anyone else, you are at risk of a sexually transmitted infection, or STI.

Ask your GP or your local sexual health clinic to test you for STIs even if you have no symptoms.

Some community family planning clinics offer STI testing as do some young people's services.

Which STIs do they test for?

Testing is done for a variety of sexually transmitted infections, including:

• Chlamydia
• Syphilis
• Herpes
• Gonorrhoea
• HIV

Are STI tests reliable?

STIs may be detected and confirmed during a physical examination by a doctor or nurse, blood tests, urine testing, and checking swabs of genital and anal secretions.

Information you give will also help with a diagnosis, such as when you last had sex, was a condom used and why you think you might have an infection.

Some test results will be available quickly; other samples may have to go off for testing in a special laboratory.

The accuracy of tests varies, depending on the type used. For example, chlamydia tests are 90-95% sensitive.

When to seek medical advice?

If you've had unprotected sex and are concerned you may have picked up an STI, seek medical advice. There may not be any symptoms, but some STIs can cause:

• Pain when urinating
• Itching, burning, or tingling of the genitals and the area around the genitals
• Blisters, sores, spots or lumps on or around the genitals and anal area
• Public lice or droppings from public lice in underwear - small white dots or black powder
• In women, yellow or green vaginal discharge or smelly discharge from the vagina
• In women, bleeding when your period is not due or after sex
• In women, pain during sex or lower abdominal pain
• In men, discharge from the penis

What if I test positive for an STI?

Tests may find you do not have an STI - or symptoms may be caused by another problem, such as thrush, not caused by having sex.

If you test positive, your sexual partners will need to be tested for STIs and possibly given treatment. It may be embarrassing, but you must tell them they may have been exposed.

Getting a positive test result can be upsetting, and counselling may be offered.

Over the counter tests: Are there any?

Some pharmacies can test for chlamydia. Chlamydia testing kits are available to use at home, but the NHS says the accuracy is variable, and if you use a home test kit, talk to your pharmacist or doctor.

Do STI tests cost money?

NHS STI tests are free, but prescription charges may need to be paid for any treatment, such as antibiotics. Test kits from a pharmacy need to be paid for.

What about STI kits over the internet?

The health regulator the MHRA says some home test kits bought over the internet to diagnose HIV and other sexually transmitted infections may give inaccurate results.

The MHRA advises people who wish to use home test kits purchased online to make sure they are CE marked and compliant with the European regulations before they use them. If there are any questions or concerns, seek medical advice.

Some kits may not be legal. If you have bought a kit which does not seem to meet UK regulations, let the MHRA know.

If you choose a home kit over a test with a healthcare professional, you also miss out on the back-up, aftercare and counselling the NHS can provide.