Urethral discharge culture is a laboratory test done on men and boys to identify germs in the urethra that may be causing an infection (urethritis). The urethra is the tube that drains urine from the bladder.
Culture of urethral discharge; Genital exudate culture; Culture - genital discharge or exudate
How the Test is Performed
The health care provider uses sterile cotton or gauze to clean the opening of the urethra at the tip of the penis. To collect the sample, a cotton swab is then gently inserted about 3/4 inch into the urethra and turned. To get a good sample, the test should be done at least 2 hours after urinating.
The sample is sent to a lab. There, it is placed in a special dish (culture). It is then watched to see if bacteria or any other germs grow.
How to Prepare for the Test
Do not urinate for 1 hour before the test. Urinating washes away some of the germs needed for accurate test results.
How the Test will Feel
There is usually some discomfort from swabbing the urethra.
Why the Test is Performed
The health care provider often orders the test when there is a discharge from the urethra. This test can detect sexually transmitted infections (STIs), such as gonorrhea and chlamydia.
A negative culture, or no growth appearing in the culture, is normal.
What Abnormal Results Mean
Abnormal results can be a sign of infection in the genital tract. These infections can include gonorrhea or chlamydia.
Fainting may occur when the swab is introduced into the urethra. This is due to stimulation of the vagus nerve. Other risks include infection or bleeding.
Craft AC, Woods GL. Specimen collection and handling for diagnosis of infectious diseases. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 63.
McCormack WM. Urethritis. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 106.
Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.