Use electrodiagnostic testing to classify the neuropathy, but do not stop there if symptoms suggest small-fiber or amyloid disease. A normal EMG does not exclude neuropathy when the pathology is predominantly small fiber.

EMG is most useful in large-fiber neuropathy with objective findings; SPEP, UPEP, and immunofixation screen for monoclonal gammopathy; Skin biopsy helps when small-fiber neuropathy is suspected; Fat pad biopsy can support amyloidosis; EMG can be normal in early or pure small-fiber neuropathy