Execution
- 1Apply the five-item CTS clinical prediction rule.
- 2Record whether shaking the hand relieves symptoms.
- 3Calculate wrist ratio and marks it positive when the index exceeds 0.67.
- 4Record Symptom Severity Scale score greater than 1.9, reduced median sensory field of digit 1, and age greater than 45 years.
- 5Count the number of positive items and interpret the post-test probability from the cluster result.
Positive outcome
The cluster becomes more convincing as more items are positive. Five of five positive items strongly increases the probability of CTS, while fewer than two positive items decreases the probability. It is a probability tool, not a stand-alone physical test.
Studies
| Study | Reliability | Sn | Sp | LR+ | LR− |
|---|---|---|---|---|---|
| Wainner et al. (2005) | acceptable for most items | NA | NA | 18.3 | NA |
| Dabbagh et al. (2020) | systematic review | NA | NA | NA | NA |
CommentWainner’s CPR is useful because it combines history, questionnaire, sensory field, wrist ratio, and age rather than relying on one provocative maneuver. The original rule reported LR+ 18.3 when all five items were positive, but it was a derivation study and later reviews describe validation evidence as limited. Use it as a structured probability aid.
High Clinical Value