Frequently Asked Questions
How do I obtain a biopsy for direct immunofluorescence?
Supplies and equipment needed - specimen vial containing transport medium (Supply T093) or dry ice, (vials with transport medium or dry ice for snap freezing are supplied by Mayo Medical Laboratories), forceps, and biopsy instruments.
- Use a sharp 4-mm punch. If biopsy specimen is to be divided, use at least a 5-mm punch. An excisional biopsy may be needed. In dividing the specimen, cut with a very sharp razor blade. Do not squeeze or twist the specimen. Make a clean cut. Specimens larger than 5 mm in diameter should be divided for adequate fixation in transport medium.
- Immediately drop specimen into provided vial of transport medium (Supply T093) or dry ice. Label vial, including patient's name, identification number, biopsy site, and date. Seal tightly.
- Complete Mayo Medical Laboratories' Request Form (Supply T060) for Dermatopathology/Immunodermatology. The following clinical data on the patient are needed for interpretation: age, gender, clinical diagnosis, biopsy site (anatomic), exposure of site to sun (exposed, unexposed), and relationship to lesional skin (perilesional, involved, uninvolved).
- Mail specimen in transport medium in containers (Supply T326) supplied by Mayo Medical Laboratories at ambient temperature. Do not mail vials filled with transport medium on dry ice. If transport medium is not available, the specimen can be shipped frozen on dry ice (without medium).
Where do I get transport media in which to send a skin tissue specimen for direct immunofluorescence (DIF)?
Transport medium can be obtained from Mayo Medical Laboratories (Supply T093). Skin or mucosal specimens can be sent by using either the transport medium or the snap-frozen procedure. The practical value of using transport medium is recognized for direct immunofluorescence testing.
The assay cannot be performed on specimens fixed in formalin.
From what skin location should I obtain a biopsy for direct immunofluorescence?
- Pemphigus and pemphigoid groups(including linear IgA bullous dermatosis and chronic bullous disease of childhood): Biopsy erythematous perilesional skin or mucosa. Avoid erosions, ulcers, and bullae while obtaining tissue adjacent to active lesions. Label as perilesional skin.
- Dermatitis herpetiformis: Biopsy normal-appearing skin, 0.5-1.0 cm away from lesion. Label as perilesional skin.
- Lupus erythematosus: Involved areas of skin such as erythematous or active borders are preferred biopsy sites to confirm the diagnosis of lupus erythematosus, either discoid or systemic. Label as involved skin. Avoid ulcers, old lesions, and facial lesions, if possible. Uninvolved, nonexposed skin is the preferred site to detect a lupus band as may be found in systemic lupus erythematosus. Should unexposed skin be desired, buttock or medial thigh is suggested. Label as uninvolved, nonexposed skin.
- Mixed connective tissue disease: Biopsy as for lupus erythematosus except when sclerodermoid features are present. For sclerodermoid features, biopsy inflamed area. Label as involved or uninvolved, exposed or nonexposed skin.
- Vasculitis and urticaria: The erythematous or active border of a new lesion is preferred. Avoid old lesions and ulcers. Label as involved skin. If appropriate skin lesion is not present, diagnosis may sometimes be made from uninvolved skin.
- Porphyria cutanea tarda: Biopsy involved skin. Avoid old lesions and ulcers. Label as involved skin.
- Lichen planus and lichenoid reactions: Biopsy involved skin. Avoid old lesions and ulcers. Label as involved skin.
How can I get a catalog or information regarding test ordering?
Contact Mayo Medical Laboratories.