Low Sensitivity of Skin Biopsy in Diagnosing Small Fiber Neuropathy in Chinese Americans

OBJECTIVES: To compare skin biopsy sensitivity for diagnosing small fiber sensory neuropathy in Chinese American and non-Chinese American patients. METHODS: We screened our skin biopsy database and performed chart review to identify Chinese and non-Chinese American patients with a high clinical suspicion for a distal small fiber sensory neuropathy, and compared the skin biopsy sensitivity. RESULTS: Twenty-three Chinese American and 32 non-Chinese American patients with the presence of distal small fiber sensory symptoms and signs were studied. Intraepidermal nerve fiber density (IENFD) (fibers/mm) at the distal leg was higher (7.1 ± 3.9), and the diagnostic sensitivity using the worldwide normative reference values of IENFD at the distal leg was lower (26.1%) in the Chinese American group than in the non-Chinese American group (5.1 ± 3.0, P < 0.05; 62.5%, P < 0.05). CONCLUSIONS: There may be ethnic differences in IENFD at the distal leg, and a different set of IENFD normative values may be developed for ethnic Chinese to improve the skin biopsy sensitivity.