The accuracy of provocative tests on diabetic patients with suspected carpal tunnel syndome and comparison with nondiabetics

Objective: Carpal tunnel syndrome in diabetic patients differ in some aspects from those in the nondiabetic population. The study was designed to evaluate the diagnostic accuracy of widely used provocative tests in the diabetic population in comparison to nondiabetic population. Materials and Methods: 87 nondiabetic and 25 diabetic hands symptomatic hands suspicious of carpal tunnel syndrome were included in this retrospective study. The presence of carpal tunnel syndrome is confirmed by nerve conduction studies. The hands were divided into DM- and DM+ groups based on patients’ diabetes mellitus history. From patient records, results of Tinel’s, Phalen’s, Durkan’s, median nerve compression, and scratch collapse tests were obtained. Sensitivity, specificity, positive predictive value, and negative predictive values of tests are calculated for each population and then compared with each other. Results: Tinel’s test had a higher sensitivity in the diabetic population. All other tests’ accuracies in diabetic patients were similar to those in diabetic patients. None of the tests had a high enough sensitivity to be used alone in either group. Scratch collapse test had very high specificity in both groups but very low sensitivity. Conclusion: The studied provocative tests have comparable accuracy for carpal tunnel syndrome in diabetic patients to those in nondiabetic patients, with Tinel even having higher sensitivity. But excluding scratch collapse test, none of the tests is strong enough to achieve a diagnosis and none is sensitive enough to rule out a disease.