Punch Skin Biopsy

A punch skin biopsy is a test that involves taking a small piece of skin to look at the nerve fibers. This is an essential test for the diagnosis of polyneuropathy affecting small nerve fibers, which is often missed with other diagnostic procedures. 


Why am I getting this test?

This test is requested by your doctor because they suspect that you may have a condition called small fiber neuropathy, which may be impossible to diagnose by other means.

What is being measured with this test?

This test measures the density of nerve fibers in the surface of the skin. This number may be reduced when there is a small fiber neuropathy. The nerve fiber density may be measured in the epidermis of the skin or in the sweat glands, or both.

How is the procedure done?

Usually two samples are taken, in order to evaluate for patterns of reduced nerve fiber density. The following steps are taken:

  • Anesthetize the skin where the specimen will be taken.
  • Specimen taking, each of which is 3 mm in diameter (like this → ).
  • Covering the site with a Band-Aid.

Is there any aftercare needed?

Yes. You will leave with the biopsy sites covered. You should keep the covering in place for at least 24 hours, and try to keep the area dry and clean for the first few days. It takes about 7 – 10 days to completely heal.

What if I see something wrong?

In that case you should contact our department or your primary care physician. We advise to watch the area for any sign of local infection, redness, itchiness, or persistent bleeding.

How long will it take to get results?

It usually takes between 14 – 21 days to get the results back. We will make the results available to your doctor as soon as we receive them.