A sample of skin, hair, fingernails, or toenails is obtained using a scalpel or other instrument. The specimen is sent to a laboratory so that it can be grown in a suitable culture medium to identify potential infectious organisms.
Purpose of the Skin, Hair, or Nail Culture
- To determine whether an abnormality of the skin, hair, or nails is caused by a bacterial, fungal, mycobacterial, or viral infection
Who Performs It
- A doctor
- Previous therapy with antibacterial, antifungal, or antiviral drugs may lead to false-negative results.
- The herpes zoster virus (which causes chicken pox and shingles) is very fragile and almost never grows in a culture, in some cases leading to false-negative results.
- Certain bacteria or fungi that are cultured may not in fact be responsible for the infection, leading to false-positive results.
Before the Skin, Hair, or Nail Culture
- No special preparation is required.
What You Experience
- If your skin is the site of the suspected infection, the doctor scrapes the outer layer of abnormal skin with a scalpel.
- When the scalp is affected, the doctor gently removes diseased hairs with a forceps and also scrapes your scalp with a scalpel.
- For nail infections, the examiner scrapes the inner surface of the nail below the tip or clips off the portion of the nail that appears abnormal.
- You may experience some minor discomfort while the sample is being collected.
- Sample collection usually takes only about 1 minute.
Risks and Complications
After the Skin, Hair, or Nail Culture
- You may resume your normal activities.
- The skin, hair, or nail specimen is placed in culture media in the laboratory and is then observed for the growth of microorganisms.
- If organisms are observed growing in culture, they are identified and classified to provide a definitive diagnosis, and appropriate therapy is begun.
- If the test is negative but the problem persists, your doctor may test another tissue sample.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media