The Sensitivity and Specificity of Nerve Conduction Studies for Diagnosis of Carpal Tunnel Syndrome: A Systematic Review

Background: The utility of nerve conduction studies (NCS) for diagnosis of carpal tunnel syndrome (CTS) has continued to be a subject of debate. Proponents of NCS assume a high sensitivity and specificity; however, many are unaware of the actual literature on this topic and the cutoff values commonly used for diagnosis. The purpose of this systematic review of the literature is to report the sensitivity and specificity of NCS for diagnosis of CTS in various studies. Methods: A literature review of PubMed and EMBASE databases was performed for all articles on NCS for diagnosis of CTS. The outcome of interest was the sensitivity and/or specificity of the NCS distal motor latency (DML) or distal sensory latency (DSL) cutoff value used to diagnose CTS in each study. Results: A total of 3066 total articles were screened and 21 were included in the review after assessment by two independent reviewers. The mean cut-off value for DSL was 3.37 ms (range 2.8-4 ms) and the mean cutoff value for DML was 4.28 ms (range 3.8-4.6 ms). Weighted mean DSL sensitivity was 73.4% and weighted mean DSL specificity was 93.6%. Weighted mean DML sensitivity was 56.2% and weighted mean DML specificity was 95.8%. Conclusions: There is significant variation in the cutoff values used for both DSL and DML. The wide range of cut-off values makes it difficult to interpret the literature, and there is a lack of high-quality studies with control groups using a priori cut-off values for diagnosis.