A skin biopsy removes cells or skin samples from the surface of your body. The sample taken from a skin biopsy is examined to provide information about your medical condition. A doctor uses a skin biopsy to diagnose or rule out certain skin conditions and diseases.Three main types of skin biopsies are:Shave biopsy. A doctor uses a tool similar to a razor to remove a small section of the top layers of skin (epidermis and a portion of the dermis).Punch biopsy. A doctor uses a circular tool to remove a small section of skin including deeper layers (epidermis, dermis and superficial fat).Excisional biopsy. A doctor uses a small knife (scalpel) to remove an entire lump or an area of abnormal skin, including a portion of normal skin down to or through the fatty layer of skin.