Why get tested?
Chlamydia is the most common sexually transmitted infection in the UK, but most people won't know they have it unless they get tested, because there are often no signs or symptoms. It's sometimes described as a 'silent epidemic'.
Chlamydia can cause long-term damage to your health if it's untreated, such as infertility (being unable to get pregnant).
It is also linked to ectopic pregnancy (a serious problem when a pregnancy develops outside of the womb), miscarriage and long-term pelvic pain in women.
Babies can get chlamydia from their mothers during birth, which can cause eye infections (conjunctivitis) and pneumonia.
Chlamydia affects men just as often as women. It can sometimes cause pain and swelling in the testicles, and may also damage a man's fertility.
Chlamydia is particularly common in under 25 year olds, so there's a national screening programme in England to help young people get tested. Testing once a year or whenever you have a new sexual partner is recommended.
It is really easy to get tested - no examination needed, just a urine sample or - for women - a self-taken vaginal swab.
Chlamydia is easily treated with special antibiotics - usually just a single dose (four tablets) taken on one day.
Make sure you're clear and get tested.