Pathology
Epidermal Nerve Fiber Density (ENFD) Testing
Epidermal Nerve Fiber Density (ENFD) Testing
Pathology Services
Conducting a skin biopsy is an easy and convenient method to evaluate and measure nerve fibers present in the epidermis, which aids in detecting and monitoring small fiber neuropathies. Research studies have indicated that skin biopsy is highly sensitive and specific in identifying the loss of small nerve fibers, and it has been employed not only for diagnostic purposes but also to track disease progression and evaluate the effectiveness of treatments. Studies have reported that ENFD (epidermal nerve fiber density) studies have an 88.4% sensitivity in detection, whereas clinical exams alone demonstrate only a 54.6% sensitivity. Additionally, the test can detect early damage to nerve fibers even in patients who do not present any symptoms.
Where Innovation Meets Precision:
Collection Procedure
Ensure all applicable supplies are readily available and prepped; biopsy tubes are appropriately labeled. Position the patient and mark the biopsy sites for anesthetization. Wear gloves to procure the biopsy collection according to ENFD procedural overview and place in correlating prelabeled Zamboni’s tube. Clean and cover the biopsy site.
Submission Requirements
Specimens in labeled Zamboni tubes are placed in the interior of each provided biohazard bag. The completed Test Requisition with accompanying patient demographic sheet and insurance information are placed in the exterior pocket of biohazard bag. Place a frozen cold pack with the biohazard bag containing specimen tube(s) into the return bubble mailer.
Specimen Storage & Transportation
The best recovery is obtained when specimens are refrigerated at 2-8°C and accompanied by the provided cold pack while in transit. Skin punch biopsies for ENFD evaluation are time dependent and must be shipped the same day for next-day delivery. If same day shipment of specimens is not feasible, refrigerate biopsies at 2-8°C for next-day shipment.
Shipping Guidelines
Personnel must be trained to pack and ship according to regulations and in a manner that corresponds to their function-specific responsibilities.
FedEx pick-up can be scheduled by calling 1-800-463-3339. Local courier service is available within El Paso, TX. Maintain an internal record of the tracking number associated with each shipment.
Collection Kits
Exova Dx specimen collection kits consist of: Biohazard bag with absorbent pad, Bubble mailer, Cold pack, prelabeled FedEx Clinical Pak, Sterile Skin Punch Collection Tray, and Zamboni’s tube(s).
Do not use materials after expiration date, refer to printed dates on bubble mailer and biohazard bag for Zamboni’s fixative expiration. Non-expired fixative must be used to ensure the integrity of the sample for accurate diagnosis.
Turnaround Times
Results from the ENFD test will be available between 10-14 days from receipt of sample.
Rejection Criteria
Specimens not in adherence to laboratory policy regarding proper collection and preservation of specimen will be rejected from acceptance.
Specimens received after 120 hours (5 days) in fixative are not accepted for processing. Additional rejection criteria include samples received with incorrect, conflicting, or missing patient identifiers on requisition and/or collection tube, sample tubes with no Zamboni’s fixative, sample tubes with no tissue present, sample tubes containing multiple tissue samples within one vial of varying origins.