carpal tunnel syndrome (cts) is a medical condition (neuropathy) that affects many individuals throughout their daily lives. the condition is caused by the compression of the median nerve in the carpal tunnel space, with repeated flexion and extension of the wrist increasing the risk of developing cts. at present, there is a lack of cts assessment tools that are easy, accurate, and less expensive to implement than traditional methods to help medical professionals, workers and employers identify potential causes of cts within the workplace. the purpose of this study was to provide evidence for the validation of a simple and easy to implement carpal tunnel compression assessment tool (ctcat) to more accurately assess cts. the ctcat is a portable testing device that can easily be used by medical professionals to assist with reducing diagnostic wait times and/or costs associated with cts. as the ctcat is a new instrument, much of the work in this study involved prototype development. a sample of 19 participants was used for this study (10 with cts, nine controls). participants with cts must have been clinically diagnosed. all participants were over 18 years of age. physical testing was completed with the ctcat based on the carpal compression test protocol (durkan, 1991). construct-related evidence of validity was provided by relating the ctcat to the boston carpal tunnel questionnaire and a 10 point likert pain scale. the findings were analyzed by using correlation techniques (i.e., intraclass and pearson’s correlations) and measures of internal consistency (i.e., cronbach’s alpha). the outcome of this study revealed that the ctcat produced reliable and valid measures when assessing participants with cts based on response time to symptom onset on two testing dates. this study builds on the research of durkan (1991) for the use of participant response time measures to cts symptom onset as an avenue to diagnose individuals with and without cts.