Lack of utility of Semmes-Weinstein monofilament testing in suspected carpal tunnel syndrome

To investigate the value of Semmes-Weinstein monofilament (SWM) testing in patients with electrodiagnostically confirmed carpal tunnel syndrome in a group of patients with symptoms compatible with carpal tunnel syndrome. A total of 119 consecutive patients with symptoms compatible with carpal tunnel syndrome were assessed. Blinded comparison of two Semmes-Weinstein monofilament testing protocols with orthodromic midpalm electrodiagnostic testing was performed. The electrodiagnostic test was considered the standard to which the results of the Semmes-Weinstein monofilament testing were measured. Fifty three percent of our patients had electrodiagnostically confirmed carpal tunnel syndrome. Using a conservative Semmes-Weinstein monofilament testing protocol the sensitivity was 98% and the specificity was 15%. The positive predictive value was 56% and the negative predictive value was 88%. Using a liberal Semmes-Weinstein monofilament testing protocol the sensitivity was 13% and the specificity was 88%. The positive predictive value was 53% and the negative predictive value was 47%. Semmes-Weinstein monofilament testing was not shown to have utility in diagnosing electrodiagnostically confirmed carpal tunnel syndrome in our population of predominantly male veterans.