Table 3.

Test characteristics of ankle pressure indices for identifying stenoses > 75% and > 50% in any limb and arterial bed in 199 subjects.

	Sensitivity (95% CI)	Specificity (95% CI)	Positive predictive value (95% CI)	Negative predictive value (95% CI)	Accuracy (95% CI)
Identifying stenosis > 75%
Resting ABI < 0.90	64% (56–72%)	75% (63–86%)	86% (77–92%)	48% (38–59%)	68% (61–74%)
Exercise ABI < 0.90	88% (82–93%)	26% (16–39%)	73% (66–80%)	50% (32–68%)	69% (62–76%)
Exercise ankle pressure decrease > 30 mmHg	4% (2–9%)	97% (89–100%)	75% (35–97%)	31% (24–38%)	32% (26–40%)
Exercise ABI > 20% decrease	67% (59–75%)	53% (39–65%)	76% (68–84%)	42% (30–53%)	63% (56–70%)
Identifying stenosis > 50%
50% Resting ABI < 0.90	61% (53–68%)	82% (67–93%)	93% (87–97%)	34% (24–44%)	65% (58–74%)
Exercise ABI < 0.90	88% (81–92%)	31% (17–48%)	84% (77–89%)	38% (21–56%)	76% (70–82%)
Exercise ankle pressure decrease > 30 mmHg	4% (1–8%)	95% (82–99%)	75% (35–97%)	19% (14–26%)	21% (16–28%)
Exercise ABI > 20% decrease	65% (51–72%)	54% (37–70%)	85% (78–91%)	27% (18–39%)	63% (56–70%)

ABI, ankle–brachial index.