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A skin or nail culture is a laboratory test to look for and identify germs that cause problems with the skin or nails.
It is called a mucosal culture if the sample involves the mucous membranes.
See also: Herpes culture
Mucosal culture; Culture - skin; Culture - mucosal; Nail culture; Culture - fingernail; Fingernail culture
How the Test is Performed
Your health care provider may use a cotton swab to collect a sample from an open skin rash or skin sore.
A sample of skin or mucous membrane is needed. For information on how this is done, see:
A small sample of a fingernail or toenail may be taken. It may take up to three weeks to get results for this type of culture.
The sample is sent to a laboratory and checked at different time periods to see if bacteria, virus, or fungus has grown. Further tests can be done to identify the specific germ that is causing your problem. This can help your doctor determine the best treatment.
How to Prepare for the Test
There is no preparation needed for a culture. For information on how to prepare for a skin or mucosal sample, see:
How the Test Will Feel
The laboratory test does not involve the patient, so it is painless. For information on how it may feel to give a skin or mucosal sample, see:
Why the Test is Performed
This test may be done to diagnose the cause of:
- A fungus infection of the skin, finger or toenail
- A skin rash or sore that appears to be infected
- A skin ulcer that is not healing
A normal result means no disease-causing germs are seen in the test sample.
Some germs normally live on the skin. These are not a sign of infection and are considered a normal finding.
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
An abnormal result means bacteria, fungus, or virus is present. This may be a sign of infection.
Common skin infections caused by bacteria include:
Common skin infections caused by fungus include:
A laboratory culture does not pose a risk to the patient. For information on risks related to removing a sample of skin or mucosal tissue, see:
Armstrong CA. Examination of the skin and approach to diagnosing skin diseases. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 444.
Habif TP, ed. Clinical Dermatology. 5th ed. Philadelphia, Pa: Saunders Elsevier: pp 491-523.
Reviewed By: 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.