Table 2. Statistical analysis of Schaeffer's test.

Result
Analysis of results for Schaeffer's test	(%)
Sensitivity	93.6
Specificity	100
Positive predictive value	100
Negative predictive value	50.8
Analysis
	Palmaris longus tendon present intraoperatively	Palmaris longus tendon absent intraoperatively
Schaeffer's test positive	453	0
Schaeffer's test negative	31	32

Note: results and analysis from Schaeffer's test to determine if the palmaris longus tendon was present or absent compared with the direct intraoperative visualization of the tendon. Note that approximately half of the time when the tendon was not detected preoperatively, the tendon was found intraoperatively (negative predictive value of 50.8%). Also, when Schaeffer's test was positive, the tendon was always identified intraoperatively (specificity and positive predictive value were 100%).