Culture - skin or mucosal biopsy
Skin or mucosal biopsy culture is a laboratory test to isolate and identify organisms that cause infection, performed on a sample obtained from the skin or mucous membranes.
How the test is performed
A sample of skin or mucous membrane can be taken by 1 of 3 methods: a shave biopsy (scraping or shaving a thin layer), a punch biopsy (using a needle or punch to obtain a small, but deeper, sample), or an excision of tissue (cutting to remove a piece of tissue).
A small piece of skin or mucous membrane is thus obtained and placed in culture media in the laboratory. It is observed for the growth of microorganisms such as bacteria and fungus. When growth is observed, the microorganisms can be identified and classified.
How to prepare for the test
The preparation is the same as for a skin biopsy. See also Gum biopsy.
How the test will feel
You will be given local anesthesia to numb the site before the biopsy is done, but you may still feel some pain or discomfort.
Why the test is performed
The test may be performed as part of the diagnosis of acute or chronic infections of the skin or mucous membranes.
The presence of no organisms (a sterile biopsy) is normal.
What abnormal results mean
Bacterial or fungal growth is present (infection).
What the risks are
There may be bleeding, slow healing, or an infection can be introduced into the biopsy site.
Sometimes the biopsy is also sent for microscopic examination by a pathologist.
by Martin A. Harms, M.D.