Table 2. Diagnostic value of OPN in individual studies of these 13 eligible publications.

Studies	AUCs (95%CI)	Thresholds	Sensitivity	Specificity	TP	FP	FN	TN
Kim [22]	NR	252 ng/ml	Early stage: 0.80	0.80	43	40	8	162
			Late stage: 0.85
Mor [23]	NR	NR	0.80	0.76	80	25	20	81
Nakae [24]	NR	489 ng/ml	0.81	0.55	26	43	6	52
Meinhold-Heerlein [25]	NR	NR	0.88	1.00	59	0	8	67
Moore [26]	0.65(0.57–0.72)	NR	0.20	0.90	13	17	54	149
Visintin [27]	0.79(0.72–0.87)	NR	0.73	0.70	114	107	42	255
Fredriksson [28]	NR	NR	0.58	0.85	11	3	8	17
Vrzalova [29]	0.804	2.91 ng/ml	0.47	0.95	9	1	10	19
Lu [30]	NR	NR	0.17	0.99	26	1	125	152
He [31]	0.68	NR	0.65	0.66	24	5	13	10
Bandiera [32]	0.92(0.87–0.97)	NR	0.81	0.81	49	23	11	97
Moszynski [33]	0.83(0.75–0.90)	28.0 ng/ml	0.72	0.89	23	9	9	73
Milivojevic [34]	0.84(0.75–0.93)	650 ng/ml	0.63	0.90	30	3	18	28

NR, not reported;—, no data available; TP, true positive rate; FP, false-positive rate; FN, false-negative rate; TN, true negative rate.