Table III.

ROC curve analysis for the initial concentration of paraquat in urine, dose of poison, arterial blood lactate and APACHE II scores in predicting fatality rate within 28 days.

Variable	Area under ROC curve	95% CI	Cutoff value	Sensitivity (%)	Specificity (%)	Youden index
Initial concentration of paraquat in urine	0.921	0.880–0.961	32.20	91.20	80.00	0.712
Dose of poison	0.887	0.842–0.931	46.50	73.70	90.00	0.637
Arterial blood lactate	0.808	0.747–0.869	2.45	69.28	75.01	0.543
APACHE II	0.648	0.570–0.726	6.50	78.11	47.52	0.256

ROC, receiver operator characteristic; 95% CI, 95% confidence interval; APACHE II, Acute Physiology and Chronic Health Evaluation II.