Which criterion has the best sensitivity in the carpal tunnel CPR?

• A. Gender
• B. Median nerve sensation of the thumb
• C. Symptom severity scale score greater than 1.9
• D. Wrist-ratio index greater than 0.67

Answer: (D)

The main idea here is screening sensitivity—how well a criterion picks up those who actually have carpal tunnel syndrome. In a carpal tunnel clinical prediction rule, you want factors that will catch as many true cases as possible, so a higher sensitivity means fewer missed diagnoses.

Wrist-ratio index greater than 0.67 stands out because it’s an objective anatomical measure that tends to be positive in a large proportion of CTS patients. If this criterion is met, you’re very likely looking at a true CTS case, so it has the highest true-positive rate among the options. It remains useful across a variety of presentations, and it’s less dependent on subjective reporting or early sensory changes.

Gender is less helpful for sensitivity because CTS occurs in both men and women, though more common in one gender; relying on gender alone will miss many cases. Median nerve sensation of the thumb can be normal in early CTS, so it doesn’t identify all affected individuals. A symptom severity scale score greater than 1.9 reflects patient-reported symptoms and tends to balance sensitivity and specificity, but it doesn’t reach the high sensitivity seen with the wrist-ratio criterion.

So, the wrist-ratio index above 0.67 provides the best sensitivity among the listed criteria.