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Table 3 Indices that assess the quality of the diagnostic test

From: Measurement of the ankle brachial index with a non-mercury sphygmomanometer in diabetic patients: a concordance study

Weighted* Kappa (95% CI)  
ABI ≤ 0.90 0.68 (0.55–0.79)
ABI ≤ 0.70 0.92 (0.81–1.00)
Sensitivity (95% CI)  
ABI ≤ 0.90 77.5% (61.5–89.2)
ABI ≤ 0.70 85.7% (57.2–98.2)
Specificity (95% CI)  
ABI ≤ 0.90 98.2% (96.1–99.3)
ABI ≤ 0.70 100% (99.0–100)
PPV (95% CI)  
ABI ≤ 0.90 83.8% (68.0–93.8)
ABI ≤ 0.70 100% (73.5–100)
NPV (95% CI)  
ABI ≤ 0.90 97.3% (94.9–98.8)
ABI ≤ 0.70 99.4% (98.0–99.9)
Positive Likelihood ratio  
ABI ≤ 0.90 42.5 (18.9–95.5)
Negative Likelihood ratio  
ABI ≤ 0.90 0.3 (0.1–0.4)
  1. BP measurement using the mercury sphygmomanometer was considered the reference method.
  2. ABI: Ankle-Brachial Index; PPV: Positive Predictive Value; NPV: Negative Predictive Value.
  3. *Quadratics weights.