Table 2.

Main findings of the included studies

Studies (author, year)	Patients/controls (n)	Sensitivity (%)	Specificity (%)	TP (n)	FP (n)	FN (n)	TN (n)
Dieplinger et al. (2009)[18]	137/114	90.00	22.00	123	89	14	25
Gong et al. (2011)[23]	84/95	77.80	55.30	65	42	19	53
Aldous et al. (2012)[16]	34/961	73.50	79.60	25	196	9	765
Santhanakrishnan et al. (2012)[22]	50/50	70.00	48.00	35	26	15	24
Santhanakrishnan et al. (2012)[22]	51/50	69.00	68.00	35	16	16	34
Yuan et al. (2012)[24]	192/81	88.20	77.80	169	18	23	63
Wang et al. (2013)[15]	68/39	74.00	74.00	50	10	18	29
Di and Peng (2013)[25]	129/35	79.00	66.00	102	12	27	23
Wen et al. (2013)[26]	354/50	99.40	54.00	352	23	2	27
Dai et al. (2014)[27]	117/300	51.20	92.70	60	22	57	278

TP: True-positive; FP: False-positive; FN: False-negative; TN: True-negative.