When EB is suspected, a skin biopsy should be taken to confirm the diagnosis and identify the type of EB. The skin biopsy must be taken from a new blister. This is best performed on an area of skin where the physician has tried to induce a blister by rubbing the skin with a pencil eraser.
Based on the results of the skin biopsy, genetic testing may be performed to confirm the specific gene and DNA mutation(s) present. In a small number of people, DNA mutation analysis is unable to identify the specific mutations that are suspected to be present based on the results of the skin biopsy.