Gram stain of urethral discharge


Gram Stain of Urethral Discharge

Urethral discharge is a visible secretion from the urethra and can be a sign of infection. A Gram stain of urethral discharge is a laboratory test that can help identify the cause of the infection. Doing a Gram stain involves examining the sample of urethral discharge under the microscope for the presence of bacteria and fungi.


  • Before performing the Gram stain, you will first need to take a sample of urethral discharge.
  • Your doctor will use a swab to gently scrape some of the discharge from your urethra.
  • This sample is then sent to a lab for examination.


  • Once the swab sample of urethral discharge has been taken, it will need to be prepared for Gram staining.
  • The sample is first smeared on a glass slide.
  • The slide is then heat-fixed by briefly passing it over a flame.
  • Next, a drop of special purple dye is added to the slide.
  • This dye is absorbed by the bacteria present in the sample.
  • The slide is then washed with a special solution called decolourizing solvent.
  • This removes the excess dye.
  • A drop of a special counterstain, typically in a yellow color, is added to the slide.
  • The slide is washed again and air-dried.
  • The prepared slide is then examined under a microscope for the presence of bacteria.


  • Gram-positive bacteria: These bacteria turn purple when exposed to the special dye used in the Gram stain and appear as purple rods under the microscope.
  • Gram-negative bacteria: These bacteria appear pink when exposed to the special dye and appear as pink rods under the microscope.


  • Gram staining is generally considered safe with no associated risks.
  • However, in rare cases, allergy to the dyes or chemicals used in the test can occur.

Why is it done?

  • Gram staining of urethral discharge, also referred to as wet mount Gram stain, is done to identify the causing organism of a urethral infection.
  • Identifying the causing organism helps determine the best treatment option, as different bacteria, fungi, and viruses can cause urethral infections.

When to do it?

  • In general, Gram staining of urethral discharge is done when a person presents with symptoms of a urethral infection, such as a discharge from the urethra.
  • However, in some cases, symptoms may not be present, so a Gram stain may be used to diagnose a latent infection.