Table 2:

Diagnostic accuracy of the modified Allen test and the heart rate–monitoring application for assessing potential primary access sites

Parameter	No. (%) of participants,‡ modified Allen test n = 219	No. (%) of participants,‡ heart rate–monitoring application n = 219	p value§
Positive test result*	38 (17.4)	18 (8.2)	0.008
Overall diagnostic accuracy, % (95% CI)	81.7 (76.0 to 86.6)	91.8 (87.3 to 95.1)	0.002
Specificity, % (95% CI)	82.8 (77.1 to 87.6)	93.0 (88.7 to 96.0)	0.001
Sensitivity, % (95% CI)	25.0 (0.6 to 80.6)	50.0 (11.8 to 88.2)	0.6
Negative predictive value, % (95% CI)	98.3 (95.2 to 99.7)	98.5 (95.7 to 99.7)	1.0
Positive predictive value, % (95% CI)	2.6 (0.7v13.8)	16.7 (3.6 to 41.4)	0.09
Positive likelihood ratio (95% CI)	1.5 (−1.1 to 4.0)	7.1 (0.4 to 13.8)
Negative likelihood ratio (95% CI)	0.9 (0.4 to 1.4)	0.5 (0.1 to 1.0)
Barbeau classification†
Class A	123 (56.2)	111 (50.7)	0.3
Class B	79 (36.1)	93 (42.5)	0.2
Class C	16 (7.3)	13 (5.9)	0.5
Class D	1 (0.5)	2 (0.9)	0.6

Note: CI = confidence interval.

^*A positive result indicates that there is inadequate collateral blood flow; this includes all true-positive and false-positive results.

^†Barbeau classification was based on conventional plethysmography results: class A, no damping of pulse tracing immediately after radial artery compression; class B, damping of pulse tracing; class C, loss of pulse tracing followed by recovery of pulse tracing within 2 minutes; class D, loss of pulse tracing without recovery within 2 minutes.

^‡Unless specified otherwise.

^§Values of p were generated using the Fisher exact test for between-arm comparisons.