Table 1.

Diagnostic criteria for CIDP based on European Federation of Neurological Societies (EFNS)/Peripheral Nerve Society (PNS) guidelines [Joint Task Force of the EFNS and the PNS, 2010].

Clinical	Clinical involvement time course reflexes	Motor or sensory dysfunction in ⩾1 limb ⩾2 months areflexia or hyporeflexia
Electrophysiological EFNS	Definite (always in ⩾2 nerves)	⩾1 of the following • motor distal latency ⩾ 50% above ULN • reduction of motor conduction velocity ⩾ 30% below LLN • prolongation of F-wave latency in 2 nerves if these have distal negative peak CMAP amplitudes ⩾20% of LLN + ⩾1 other demyelinating parameter in ⩾1 nerve • partial motor conduction block: ⩾50% amplitude reduction • abnormal temporal dispersion (>30% duration increase) • distal CMAP duration increase in ⩾1 nerve + ⩾1 other demyelinating parameter
	Probable	⩾30% amplitude reduction of CMAP in ⩾2 nerves
	Possible	As in ‘definite’ but in only 1 nerve
Pathologic	Sural nerve biopsy	Demyelination and remyelination supportive: subperineurial or endoneurial edema mononuclear cell infiltration ‘onion-bulb’ formation
Laboratory	Cerebrospinal fluid	Cell count <10/mm3 VDRL negative supportive: elevated protein

CMAP, compound muscle action potential; LLN, lower limit of normal; ULN, upper limit of normal; VDRL, Venereal disease research laboratory.