Table 1.

Summary of included studies.

Author	Year	Country	Case/controls	Assay method	Cut-off	TP	FP	FN	TN	QUADAS
Iwahori et al. [15]	2012	Japan	49/37	ELISA	6.56 ng/mL	44	0	5	37	13
Liu et al. [16]	2013	China	190/244	ELISA	82.61 pmol/L	121	43	69	201	12
Ucar et al. [17]	2014	Turkey	64/38	ELISA	67.5 pmol/L	56	13	8	34	12
Wang et al. [18]	2014	China	49/30	ELISA	84.19 pmol/L	34	2	15	28	11
Yamashita et al. [14]	2011	Japan	102/74	ELISA	50.3 pmol/L	76	14	26	60	12
Yu et al. [19]	2014	China	47/31	ELISA	149.145 pmol/L	34	3	13	28	11
Xiao et al. [20]	2014	China	214/76	ELISA	NR	147	8	67	68	12

TP: true positive; FP: false positive; TN: true negative; FN: false negative; NR: not reported; ELISA: enzyme-linked immunosorbent assay.