Objective The aim of our study was to assess agreement between different case definitions of carpal tunnel syndrome (CTS) for epidemiological studies. Methods We performed a literature search for papers suggesting case definitions for use in epidemiological studies of CTS. Using data elements based on symptom questionnaires, hand diagrams, physical examinations and nerve conduction studies collected from 1107 newly-hired workers, each subject in the study was classified according to each of the case definitions selected from the literature. We compared each case definition to every other case definition, using the Kappa statistic to measure pairwise agreement on whether each subject met the case definition. Results We found six unique papers in a twenty year period suggesting a case definition of CTS for use in population-based studies. We extracted seven case definitions. Definitions included different parameters: symptoms only, symptoms and physical examination, symptoms and either physical examination or median nerve conduction study, symptoms and nerve conduction study. When applied to our study population, the prevalence of CTS using different case definitions ranged from 2.5% to 11.0%. The percentage of misclassification was between 1 to 10%, with generally acceptable levels of agreement (Kappa values ranged from 0.30 to 0.85). Conclusion Different case definitions resulted in widely varying prevalences of CTS. Agreement between case definitions was generally good, particularly between those that required very specific symptoms or the combination of symptoms and physical examination or nerve conduction. The agreement observed between different case definitions suggests that the results can be compared across different research studies of risk factors for CTS.

Background Physical examination is often used to screen workers for carpal tunnel syndrome (CTS). In a population of newly-hired workers, we evaluated the yield of such screening. Methods Our study population included 1108 newly-hired workers in diverse industries. Baseline data included a symptom questionnaire, physical exam, and bilateral nerve conduction testing of the median and ulnar nerves; individual results were not shared with the employer. We tested three outcomes: symptoms of CTS, abnormal median nerve conduction, and a case definition of CTS that required both symptoms and median neuropathy. Results Of the exam measures used, only Semmes-Weinstein sensory testing had a sensitivity value above 31%. Positive predictive values were low, and likelihood ratios were all under 5.0 for positive testing and over 0.2 for negative testing. Conclusion Physical examination maneuvers have a low yield for the diagnosis of CTS in workplace surveillance programs and in post-offer, pre-placement screening programs.

Objective We evaluated the utility of physical examination maneuvers in the prediction of carpal tunnel syndrome (CTS) in a population-based research study. Methods We studied a cohort of 1108 newly employed workers in several industries. Each worker completed a symptom questionnaire, a structured physical examination, and nerve conduction study. For each hand, our CTS case definition required both median nerve conduction abnormality and symptoms classified as “classic” or “probable” on a hand diagram. We calculated the positive predictive values and likelihood ratios for physical examination maneuvers, in subjects with and without symptoms. Results The prevalence of CTS in our cohort was 1.2% for the right hand and 1.0% for the left hand. The likelihood ratios of a positive test for physical provocative tests ranged from 2.0 to 3.3, and those of a negative test from 0.3 to 0.9. The post-test probability of positive testing was less than 50% for all strategies tested. Conclusion Our study found that physical examination, alone or in combination with symptoms, was not predictive of CTS in a working population. We suggest using specific symptoms as a first level screening tool, and nerve conduction study as a confirmatory test, as a case definition strategy in research settings.