PCR detection of Chlamydia trachomatis

Have you had unprotected sex, a new partner or burning when urinating? Chlamydia is the most common bacterial sexually transmitted infection, and most infected people have no symptoms. PCR detection of Chlamydia trachomatis from urine or a swab reliably shows whether you are infected, and infection is easily treated with an antibiotic.

Who is this test for

• people with burning when urinating or vaginal or urethral discharge;
• women with bleeding after intercourse or between periods and lower abdominal pain;
• men with testicular pain or swelling;
• after unprotected intercourse or a change of partner;
• people whose partner has been diagnosed with chlamydia or another sexually transmitted infection;
• sexually active women under 25, for whom professional guidelines recommend annual testing even without symptoms;
• women planning pregnancy or infertility treatment, on a doctor’s recommendation.

What the test reveals

PCR finds genetic traces of Chlamydia trachomatis in urine or a swab. It is highly sensitive, detecting infection even without symptoms. This matters because untreated chlamydia in women may affect the uterus and fallopian tubes, causing pelvic inflammation, chronic pain, ectopic pregnancy and infertility. In men it may cause epididymitis, and in pregnancy it can be transmitted to the newborn.

Chlamydia is often tested alongside other pathogens. You can also check for gonorrhoea, mycoplasmas and trichomonas.

The test and preparation

Women provide a vaginal swab or first-catch urine; they can also collect a vaginal swab themselves at home using a self-sampling kit obtained from a branch and return the sample to the branch. Men provide first-catch urine or a genital swab.

For urine, the first morning urination is best, or after not urinating for at least two hours. Collect only the first stream, around 10 to 20 mL. Do not take a swab during menstruation; avoid vaginal preparations for two to three days beforehand. Bring urine as soon as possible, preferably within 2 hours. If you have already started antibiotics, mention this when submitting the sample. Throat or rectal infection does not show in urine or a genital swab; if you had oral or anal intercourse, tell your doctor, who may request a sample from that site.

If you have no symptoms, test approximately two weeks after a risky contact because earlier testing may miss infection. If you have symptoms, do not wait.

What your results mean

• Positive: you have chlamydia. It is treated with an antibiotic prescribed by a doctor; partners from the past several months also need testing and treatment. Avoid intercourse until you and your partner have finished treatment, as instructed by the doctor.
• Negative: chlamydia was not found. If fewer than two weeks have passed since risky contact or symptoms persist, a doctor may recommend repeating the test or other investigations.

A doctor interprets the result alongside symptoms and examination. Follow-up testing after treatment is generally unnecessary except in pregnancy or persistent symptoms, and is then not performed earlier than three to four weeks. Because reinfection is common, repeating the test approximately three months after treatment is useful.

How to arrange testing

The test is performed without a referral or appointment. A nurse takes the swab; urine samples or swabs collected at home can be submitted at any of our branches (listed on the Contactpage). Testing is also available anonymously, without disclosing personal details. Prices for all tests and panels are listed in the price list. Chlamydia alongside mycoplasmas and ureaplasma is included in the STD4 basic panel, and with gonorrhoea, trichomonas and HPV in the STD7 extended panel. Other options are described on the Sexually transmitted infection testing.

Frequently asked questions

How soon after intercourse can I test for chlamydia?

Testing is most reliable approximately two weeks after risky contact. If you have symptoms, test immediately.

Can chlamydia go away by itself?

Sometimes, but this should not be relied on. Untreated infection may persist for months without symptoms, damage the fallopian tubes and spread to partners.

Can I test using urine instead of a swab?

Yes. First-catch urine is a reliable sample for men and a good choice for women, although a vaginal swab is slightly more sensitive in women.

Do I have to tell my partner?

Yes, the partner needs testing and treatment even without symptoms; otherwise the infection returns. A doctor can advise how best to do this.