Screening for Chlamydial Infection: Recommendations from the U.S. Preventive Services Task Force

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The summary below is from the full reports titled "Screening for Chlamydial Infection: U.S. Preventive Services Task Force Recommendation Statement" and "Screening for Chlamydial Infection: An Evidence Update for the U.S. Preventive Services Task Force." They are in the 17 July 2007 issue of Annals of Internal Medicine (volume 147, pages 128-134 and pages 135-142). The first report was written by the U.S. Preventive Services Task Force; the second report was written by D.S. Meyers, H. Halvorson, and S. Luckhaupt.

Who developed these recommendations?

The U.S. Preventive Services Task Force (USPSTF), a group of health experts that makes recommendations about preventive health care.

What is the problem and what is known about it so far?

Sexually transmitted infections spread from 1 person to another during sexual relations. Chlamydia trachomatis is a bacterium that causes a common sexually transmitted infection (chlamydia). Chlamydia can cause discharge from the vagina or penis, pain with urination, or abdominal pain. However, some people with chlamydia have no symptoms. Treatment with antibiotics relieves symptoms, stops the spread of infection, and prevents complications of the infection. In women, chlamydia can cause difficulties in becoming pregnant (infertility). Infections in pregnant women can lead to premature birth and other problems in newborns.

Doctors can test for chlamydia by using a swab of the cervix taken during a pelvic examination for women, a swab of the penis in men, or urine samples in women or men. Because some people with chlamydial infection have no symptoms and do not know that they have an infection, screening healthy people for chlamydia might identify some in whom treatment could prevent complications and spread of the infection. Screening means to look for a disease in people with no symptoms. The tests for chlamydia are not perfect, so screening can mistakenly identify some people as having infection when they really don't have it, leading to unnecessary worry and treatment. Screening also costs money. However, the benefits of screening are usually more likely to outweigh the potential drawbacks or costs for people with a reasonable chance for infection.

How did the USPSTF develop these recommendations?

The USPSTF reviewed published research to evaluate the benefits and harms of screening for chlamydial infection.

What did the authors find?

Women are at increased risk for chlamydia if they have 1 or more of the following factors:

1) They are 24 years of age or younger and are sexually active; 2) they have previously had chlamydia or another sexually transmitted infection; 3) they have new or multiple sexual partners; 4) they do not use condoms regularly; or 5) they exchange sex for money or drugs.

Previous studies show that the benefits of screening nonpregnant and pregnant women at increased risk for infection clearly outweigh the harms. For pregnant and nonpregnant women who are not at increased risk, the benefits of screening outweigh the harms only to a small degree. Research is not available to determine the benefits and harms of screening men for chlamydia.

What does the USPSTF suggest that patients and doctors do?

All sexually active, nonpregnant women age 24 years or younger should be screened for chlamydia. Nonpregnant women who are age 25 years or older should be screened only if they are at increased risk for infection. All pregnant women age 24 years or younger and older pregnant women who are at increased risk for chlamydial infection should be screened. There is not enough available information to know whether men should be screened routinely for chlamydia.

What are the cautions related to these recommendations?

These recommendations apply only to screening, which means looking for chlamydia in people with no symptoms of infection.