Urethral discharge culture
Urethral discharge culture is a laboratory test done on men and boys to identify infection-causing germs in the urethra (the tube that drains urine from the bladder) and genital tract.
Alternative Names
Culture of urethral discharge; Genital exudate culture; Culture - genital discharge or exudate
How the test is performed
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 turned. To get a good sample, the test should be done at least 1 hour after urinating.
The sample is sent to a lab where it is placed in a special dish (culture) and 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. Urination will wash 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
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
.
Normal Values
A negative culture, or no growth appearing in the culture, is normal.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What abnormal results mean
Abnormal results can be a sign of infection in the genital tract. These infections can include gonorrhea or chlamydia.
See also: Chlamydial urethritis, male
What the risks are
Fainting (caused by stimulation of the vagal nerve) occasionally occurs when the swab is introduced into the urethra. Other risks include infection or bleeding.
References
McCormack WM. Urethritis. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 106.
Cohen MS. Approach to the patient with a sexually transmitted disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 293.
Workowski KA, Berman S; Centers for Disease Control and Prevention (CDC). Sexually transmitted diseases treatment guidelines, 2010. MMWR Recomm Rep. 2010 Dec 17;59(RR-12):1-110.
Updated: 8/12/2011
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.