Lack of predictive power of the "tethered" median stress test in suspected carpal tunnel syndrome

OBJECTIVE: To investigate the value of the "tethered" median nerve stress test (TMST) in predicting electrodiagnostically confirmed carpal tunnel syndrome (CTS) in patients with symptoms suggestive of CTS. STUDY DESIGN: Blinded comparison of a clinical diagnostic test with neurophysiologic testing. SETTING: Portland (OR) Veterans Administration Medical Center Electrodiagnostic Laboratory. PATIENTS: One hundred two consecutive patients referred for symptoms suggestive of CTS. Study inclusion criteria were referral for evaluation of symptoms of paresthesia (with or without pain) inclusive of the median nerve distribution distal to the wrist. RESULTS: Fifty-seven percent of referred patients had electrodiagnostically confirmed CTS. The sensitivity of the TMST was 50%. The specificity was 59.1%. The positive predictive value was 61.7%. The negative predictive value was 47.3%. CONCLUSION: The TMST does not have utility in predicting electrodiagnostic consult results in veteran patients with symptoms suggestive of CTS.