Variable Cut-off values Sens. (%) Spec. (%) PPV. (%) NPV. (%) Accuracy (%)
Serum NO > 32 mmol/l 86.7 95.6 97.5   78.2 95
Mean RI > 0.63 96.7 95.6 95.4 94.4 97.3
Table 4: Cut-off values for serum NO and mean RI between patients and controls.