A skin biopsy is a procedure in which a sample of skin tissue is removed, processed, and examined under a microscope.

Several different methods may be used to obtain a skin sample, depending on the size and location of the abnormal area of skin, called a skin lesion. The skin sample is placed in a solution, such as formaldehyde, or in a sterile container if infection is suspected. In each of these procedures, the tissue is processed and then examined under a microscope.

Skin biopsies most often are done to diagnose skin cancer, which may be suspected when an abnormal area of skin has changed color, shape, size, or appearance or has not healed after an injury. Skin cancers are the most common type of cancers.

Early diagnosis of a suspicious skin lesion and skin biopsy can help identify skin cancers and lead to early treatment.

Why It Is Done

A skin biopsy is done to diagnose a:

• Skin condition (if it is not already clear what the condition is), such as psoriasis.
• Disease, such as skin cancer.
• Bacterial or fungal skin infection.

How To Prepare

Before a skin biopsy, tell your doctor if you:

• Are taking any medications, particularly anti-inflammatory medicines such as prednisone. Anti-inflammatory medicines may change the way your biopsy looks under the microscope.
• Are allergic to any medicines.
• Have had any bleeding problems or are taking blood-thinning medicines, such as aspirin or warfarin (Coumadin).
• Are or might be pregnant.

No special preparation is needed before having this test.

You may be asked to sign a consent form. Talk to your health professional about any concerns you have regarding the need for the test, its risk, how it will be done, or what the results will indicate. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).