Table 4. Diagnostic accuracy of pleural YKL-40 and pleural YKL-40/serum YKL-40 ratio in pleural effusions.

Diagnosis	Parameter	AUC	Cutoff value	Sensitivity	Specificity	PPV	NPV	LR	Accuracy
Exudate	Pleural YKL-40	0.770 (0.657-0.884)	215	0.73	0.73	0.87	0.53	2.8	0.73
	YKL-40pl/YKL-40s	0.638 (0.510-0.767)	1.2	0.57	0.65	0.80	0.38	1.6	0.60
TPE	Pleural YKL-40	0.632 (0.488-0.777)	217	0.75	0.52	0.22	0.92	1.5	0.56
	YKL-40pl/ YKL-40s	0.825 (0.710-0.940)	1.5	0.75	0.72	0.32	0.94	2.6	0.72
MPE	Pleural YKL-40	0.580 (0.442-0.718)	218	0.54	0.58	0.33	0.77	1.3	0.57
	YKL-40pl/ YKL-40s	0.520 (0.379-0.662)	1.2	0.54	0.51	0.30	0.75	1.1	0.52
PPE	Pleural YKL-40	0.610 (0.471-0.749)	218	0.56	0.57	0.35	0.76	1.3	0.57
	YKL-40pl/ YKL-40s	0.584 (0.448-0.719)	1.2	0.56	0.56	0.34	0.76	1.2	0.56

TPE, tuberculous pleural effusion; MPE, malignant pleural effusion; PPE, parapneumonic effusion; AUC, area under curve; PPV, positive predictive value; NPV, negative predictive value; LR, likelihood ratio.