Dynamic ultrasound monitoring of intraperitoneal effusion for predicting complications after laparoscopic gastrectomy

Table 12 Results of receiver operating characteristic curve indicators

Indicators	Cut-off value	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	AUC	Youden’s index
CRP (mg/L)	48.5	80	78.3	64	89.3	0.852	0.583
PCT (ng/mL)	0.47	82.9	81.7	67.7	91.2	0.874	0.646
WBC (× 109/L)	10.8	68.6	70	52.9	80.4	0.732	0.386
Combined model	-	88.6	85	0.912	Combined model	-	88.6

The combined model (postoperative day 3 procalcitonin > 0.47 ng/mL + mixed effusion) showed superior predictive performance (area under the curve = 0.912) compared to individual markers. PPV: Positive predictive value; NPV: Negative predictive value; AUC: Area under the curve; CRP: C-reactive protein; PCT: Procalcitonin; WBC: White blood cell count.