Gram stain of urethral dischargeUrethral discharge Gram stain; Urethritis - Gram stain
A Gram stain of urethral discharge is a test used to identify bacteria in fluid from the tube that drains urine from the bladder (urethra).
How the Test is Performed
Fluid from the urethra is collected on a cotton swab. A sample from this swab is applied in a very thin layer to a microscope slide. A series of stains called a Gram stain is applied to the specimen.
The stained smear is then examined under the microscope for the presence of bacteria. The color, size, and shape of the cells help identify the type of bacteria causing the infection.
How to Prepare for the Test
This test is often performed in the health care provider's office.
How the Test will Feel
You may feel pressure or burning when the cotton swab touches the urethra.
Why the Test is Performed
The test is performed when an abnormal urethral discharge is present. It may be performed if a sexually transmitted infection is suspected.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.
What Abnormal Results Mean
Abnormal results may indicate gonorrhea or other infections.
Gonorrhea is a common sexually transmitted infection (STI).
There are no risks.
A culture of the specimen ( urethral discharge culture ) should be performed in addition to the gram stain. More advanced tests (such as PCR tests) may also be done.
Urethral discharge culture
Urethral discharge culture is a laboratory test done on men and boys. This test is used to identify germs in the urethra that may be causing urethri...
Augenbraun MH, McCormack WM. Urethritis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, Updated Edition . 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 109.
Swygard H, Cohen MS. Approach to the patient with a sexually transmitted infection. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 285.
Gram stain of urethral discharge - illustration
The gram stain procedure is a method of staining microorganisms on a slide using crystal violet to be viewed later under a microscope.
Gram stain of urethral discharge
Urinary tract infection
Review Date: 10/4/2016
Reviewed By: John D. Jacobson, MD, Professor of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda Center for Fertility, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.