Lew HL, Date ES, Pan SS, Wu P, Ware PF, Kingery WS. Sensitivity, specificity, and variability of nerve conduction velocity measurements in carpal tunnel syndrome. Objective To explore the diagnostic values of 8 commonly used electrodiagnostic techniques for measuring median nerve conduction velocity (NCV) in carpal tunnel syndrome (CTS). Design Sensitivity and specificity analyses. Setting A hospital-based electrodiagnostic laboratory. Participants Forty-four normal hands and 136 symptomatic hands. Interventions Not applicable. Main outcome measures (1) Long-segment studies: antidromic wrist-to-digit sensory NCV without subtraction, (2) short-segment studies: transcarpal palm-to-wrist mixed NCV without subtraction, and (3) 2 segment studies: antidromic transcarpal sensory NCV with subtraction (differential calculation from wrist-to-digit and palm-to-digit segments). Both onset and peak latency values were obtained for calculating the NCV. Sensitivity, specificity, and coefficient of variance were calculated for each NCV study. Results The short-segment, onset latency-based transcarpal mixed NCV yielded the highest sensitivity (75%). Conclusions Results from measurement of a single, short-nerve segment tended to be superior to results obtained by either long-segment studies or differential subtraction between 2 segments of the same nerve in the electrodiagnosis of CTS. Explanations for our results are offered from both electrophysiologic and statistical perspectives.