Development and validation of diagnostic criteria for carpal tunnel syndrome

Purpose: To develop clinical diagnostic criteria for carpal tunnel syndrome (CTS) that modeled the clinical diagnostic practices of experts, Methods: Fifty-seven clinical findings associated with CTS had been ranked previously in order of diagnostic importance using Delphi as a method of establishing consensus among a panel of expert clinicians. The 8 most highly ranked criteria then were placed into all possible combinations to create 256 unique case histories. Two new panels of experts rated these case histories. One panel made a binary evaluation as to whether the case history did or did not represent CTS. This allowed the development of a logistic regression model that had the probability of carpal tunnel syndrome as the dependent variable and the weighted diagnostic criteria as the independent variables. This model then was validated against the judgments of the second panel of clinicians who estimated the probability of CTS for each of the same case histories. Results: The correlation between the probability of CTS predicted by the model and the panel of clinicians was 0.71. Conclusions: The most important clinical diagnostic criteria for CTS as identified from a larger pool of potential diagnostic items through a consensus approach using Delphi were weighted and found to correlate well with the judgments of a new panel of clinicians. By improving the consistency of the diagnosis of CTS these criteria should lead to more effective treatment and a better understanding of the effect of workplace exposures in the development of this condition. A methodology that emphasizes a rigorous approach to item generation and item reduction through expert consensus, followed by validation, may represent a template for establishing consensus among experts on other controversial clinical issues.