Performing a Punch Biopsy in your office
*Do not inject anesthesia into biopsy site, the injection should be around the biopsy site and directly below.
1. Select area to be biopsied.
2. The skin is cleansed with povidone-iodine solution and anesthetized with 2 percent lidocaine with epinephrine. A 30-gauge needle is used to administer the anesthetic to limit discomfort.
3. The lines of least skin tension should be identified for the area to be biopsied. For example, on the arm, these lines run perpendicular to the long axis of the extremity. The incision line created by the suturing after the biopsy is performed will be oriented parallel to the lines of least skin tension. Physicians who cannot recall the line orientation for a specific body area should consult the widely published drawings of these lines.
4. The skin surrounding the biopsy site is stretched with the thumb and index finger of the non dominant hand. The skin is stretched perpendicular to the lines of least skin tension. When the skin relaxes after the biopsy is performed, an elliptical-shaped wound remains that is oriented in the same direction as the lines of least skin tension.
5. The punch biopsy instrument is held vertically over the skin and rotated downward using a twirling motion created by the first two fingers on the dominant hand. Once the instrument has penetrated the dermis into the subcutaneous fat, or once the instrument reaches the hub, it is removed.
6. The cylindrical skin specimen is elevated with the anesthesia needle held in the non- dominant hand. The use of forceps is discouraged because these instruments frequently cause crush artifact. Scissors held in the dominant hand cut the specimen free from the subcutaneous tissues. The cut is made below the level of the dermis.
7. Antibiotic ointment and a bandage are then applied.