What Is Small-Fiber Dx®?
Even when nerve conduction studies are normal, patients may still have isolated small fiber neuropathy. Because standard electrodiagnostic studies do not assess small fibers, recognizing this diagnostic gap can help clinicians make more informed decisions.
By incorporating intraepidermal nerve fiber density (IENFD) assessment through a convenient, minimally invasive skin punch biopsy, alongside traditional methods of evaluating large fiber function, clinicians can add objective evidence to their diagnostic approach.1
What is Small-Fiber Dx?
The Small-Fiber Dx test uses a combination of immunofluorescent techniques to provide detailed quantification of intraepidermal nerve fiber density (IENFD). This provides clinicians with an evidence-based tool to evaluate the relative health and density of peripheral sensory nerves, helping to support the diagnosis of small fiber neuropathy.
What can Small-Fiber Dx tell you?
Small-Fiber Dx measures IENFD using Protein Gene Product 9.5 (PGP 9.5) staining to help support the diagnosis of a small fiber neuropathy.
The test also includes a Congo red assay to assess amyloid deposits, a potential cause for neuropathy, and provides a detailed analysis of underlying skin conditions that may mimic neuropathic symptoms, such as itching and burning, using Hematoxylin & Eosin (H&E) staining, helping guide a potentially challenging diagnosis.
How is the test performed?
Small-Fiber Dx uses immunofluorescence techniques to provide detailed assessment of IENFD. The test uses three small skin biopsies collected during an in-office procedure.
Test kits are available at no charge, and the collected biopsies are shipped at room temperature to a CLIA-certified and CAP-accredited laboratory in Scottsdale, Arizona.
Why should your practice offer Small-Fiber Dx?
Objective evidence of reduced IENFD can help you identify small fiber neuropathy and other underlying causes of your patients’ neuropathic symptoms, supporting more tailored treatment plans.
CND offers insurance benefits verification and case reviews with our Medical Affairs team to help seamlessly integrate the test into your practice workflow.
To learn more and order test kits, visit cndlifesciences.com/small-fiber-dx
1Furia A, Liguori R, Donadio V. Small-fiber neuropathy: an etiology-oriented review. Brain Sci. 2025;15(2):158.
