A gram stain of a skin lesion is a laboratory test that uses special stains to detect and identify bacteria in a sample from a skin sore. The gram stain method is one of the most commonly used techniques for the rapid diagnosis of bacterial infections.
Alternative Names: Skin lesion gram stain
How the test is performed:
Your health care provider will remove a sample of tissue from the skin sore. For information on how this is done, see the article on skin lesion biopsy .
The sample is sent to a laboratory, where it is applied in a very thin layer to a glass slide. A series of different colored stains is applied to the sample. A laboratory team member examines the stained slide under a microscope, checking for bacteria. The color, size, and shape of the cells help identify the infecting organism.
How to prepare for the test:
No preparation is needed for the laboratory test.
How the test will feel:
The laboratory test is painless. For information on what it feels like to have the skin sample removed, see skin lesion biopsy .
Why the test is performed:
Your doctor may order this test if you have signs of an infected skin sore. The test is done to determine which bacteria is causing the infection.
Normal Values:
The test is normal if no bacteria are identified.
What abnormal results mean:
An abnormal result means bacteria have been found in the skin lesion. Further tests are needed to confirm the results.
What the risks are:
There are no risks related to the laboratory test. For information on risks related to the removal of a skin sample, see skin lesion biopsy .
Special considerations:
A skin or mucosal culture may be done along with this test. Other studies are often done on a skin sample to determine if cancer is present.
Review Date: 12/3/2007 Reviewed By: D. Scott Smith, M.D., MSc, DTM&H, Chief of Infectious Disease & Geographic Medicine, Kaiser Redwood City, CA & Adjunct Assistant Professor, Stanford University. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
