Table 4.

PCT, PCT/Alb, CRP, and CRP/Alb were analyzed by the ROC curve.

Variable	AUC	95% Cl	Sensitivity (%)	Specificity (%)	Youden index	Critical value
PCT	0.807	0.740–0.875	76.6	69.2	0.458	18.455
PCT/Alb	0.864	0.807–0.922	79.7	83.2	0.629	0.6827

Alb, Serum albumin; PCT, procalcitonin; PCT/Alb, the ratio of PCT to Alb.