Table 1. Optimal cut-off values of HE4 for diagnosis between lung cancer and healthy control and benign lung disease (sensitivity, specificity, AUC, and 95% CI).

	AUC	95% CI	Cut-off (pmol/L)	Sensitivity	Specificity	Youden's index J	SE	P
Healthy control	0.84	0.78–0.89	41.1	0.908	0.449	0.353	0.026	< 0.0001
			57.9	0.806	0.770	0.576
			74.4	0.633	0.908	0.541
Benign lung disease	0.71	0.62–0.79	46.2	0.890	0.333	0.223	0.042	< 0.0001
			70.0	0.660	0.684	0.362
			134.3	0.260	0.930	0.207

Abbreviations: HE4, human epididymis protein 4; AUC, area under the curve; CI, confidence interval; SE, standard error of AUC.