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Urethral discharge culture is a laboratory test done on men and boys to identify organisms in the urethra (the tube that drains urine from the bladder) and genital tract that cause infection.

The health care provider cleans the opening of the urethra (at the tip of the penis) with sterile gauze or cotton. To collect the sample, a cotton swab is then gently inserted about 3/4 inch into the urethra and rotated. To get a good sample, the test should be done at least 1 hour after urinating.

The sample is sent to a laboratory where it is placed in a special dish (culture) and watched to see if bacteria or any other organisms grow. The laboratory technician isolates and identifies any organisms that grow on the culture. The drainage may be examined on a slide under the microscope and then confirmed by culture.

Do not urinate for 1 hour before the test. Urination will wash away some of the organisms needed to obtain an accurate culture.

There is usually some discomfort from swabbing the urethra.

Often the test is performed when there is a discharge from the urethra. This test can detect sexually transmitted diseases, such as gonorrhea and chlamydia.

A negative culture, or no growth appearing in the culture, is normal.

Abnormal results can indicate infection within the genital system. These infections can include gonorrhea or chlamydia.

See also:

• Chlamydial urethritis, male
• Chronic urethritis
• Gonococcemia (disseminated)

Fainting (caused by stimulation of the vagal nerve) occasionally occurs when the swab is introduced into the urethra. Other risks include infection or bleeding.

A comparable test for women and girls is an endocervical culture.

Culture of urethral discharge; Genital exudate culture; Culture - genital discharge or exudate

Workowski KA, Berman SM. Diseases characterized by urethritis and cervicitis. Sexually transmitted diseases treatment guidelines 2006. Centers for Disease Control and Prevention. MMWR Morb Mortal Wkly Rep 2006 Aug 4;55(RR-11):35-49.

Centers for Disease Control and Prevention (CDC). Update to CDC's sexually transmitted diseases treatment guidelines, 2006: fluoroquinolones no longer recommended for treatment of gonococcal infections. MMWR Morb Mortal Wkly Rep 2007 Apr 13;56(14):332-6.

Updated by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.