Nerve biopsy is recommended for patients with severe neurological deficits that do not meet the electrophysiological criteria for CIDP; patients with coexisting conditions that may confound the diagnosis, such as diabetes and hereditary neuropathy; or patients with coexisting conditions that may affect the choice of treatment, such as co-infection with HIV or hepatitis C; variants of CIDP, such as pure sensory; or patients who do not respond well to hormone, gammaglobulin and plasma exchange therapy and require nerve biopsy before starting other more toxic treatments, preferably from nerves with abnormal findings on electrophysiological examination.