Diagnosis

The Centers for Disease Control and Prevention recommends chlamydia screening for:

• Sexually active women age 25 or younger. The rate of chlamydia infection is highest in this group, so a yearly screening test is recommended. Even if you've been tested in the past year, get tested when you have a new sex partner.
• Pregnant women. You should be tested for chlamydia during your first prenatal exam. If you have a high risk of infection — from changing sex partners or because your regular partner might be infected — get tested again later in your pregnancy.
• Women and men at high risk. People who have multiple sex partners, who don't always use a condom or men who have sex with men should consider frequent chlamydia screening. Other markers of high risk are current infection with another sexually transmitted infection and possible exposure to an STI through an infected partner.

Screening and diagnosis of chlamydia is relatively simple. Tests include:

• A urine test. A sample of your urine is analyzed in the laboratory for presence of this infection.

• A swab. For women, your doctor takes a swab of the discharge from your cervix for culture or antigen testing for chlamydia. This can be done during a routine Pap test. Some women prefer to swab their vaginas themselves, which has been shown to be as diagnostic as doctor-obtained swabs.

  For men, your doctor inserts a slim swab into the end of your penis to get a sample from the urethra. In some cases, your doctor will swab the anus.

If you've been treated for an initial chlamydia infection, you should be retested in about three months.