Receiver operating characteristic curve: Prediction of outcome (mortality) using serum levels of NO.
The predicted probability of mortality was assessed by using ROC curve. We used serum levels of NO as the predictive variable and mortality as the outcome variable. Sensitivity and specificity were calculated using Fisher’s exact test. ROC was plotted using 1‐specificity (FPF) on X‐axis and sensitivity (TPF) on Y‐axis for the predictor variable. A profile with area under the curve (AUC), (C) = 0.5 shows no predictable ability whereas (C) = 1 has a perfect predictable ability. As shown in Figure 3, the area under the ROC curve, C = 0.96 indicated a perfect predictive ability of mortality.