Table 2. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool for quality assessment of studies selected for the meta-analysis.

Study	Risk of bias				Applicability concerns
	Patient selection	Index test	Reference standard	Flow and timing	Patient selection	Index test	Reference standard
Yagi K et al. 2002 [14]	?	☺	?	☺	?	☺	☺
Yagi K et al. 2002 [15]	?	?	☺	☺	?	☺	☺
Nakagawa S et al. 2003 [16] a	☺	☺	☺	☺	☺	☺	☺
Nakagawa S et al. 2003 [16] a	☺	☺	☺	☺	☺	☺	☺
Nakagawa S et al. 2003 [16] a	☺	☺	☺	☺	☺	☺	☺
Yang JM et al. 2003 [17]	?	?	?	☺	?	☺	☺
Egi Y et al. 2006 [18]	☺	☺	?	☹	☺	☺	☺
Anagnostopoulos GK et al. 2007 [19]	☺	?	☺	☺	?	☺	☺
Bansal A et al. 2008 [20]	?	?	☺	☺	?	☺	☺
Gonen C et al. 2009 [21] b	?	☺	?	☺	☺	☺	☺
Gonen C et al. 2009 [21] b	?	☺	?	☹	☺	☺	☺
Gonen C et al. 2009 [21] b	☺	☺	?	☺	☺	☺	☺
Gonen C et al. 2009 [21] b	☺	☺	?	☺	☺	☺	☺
Tahara T et al. 2009 [22]	?	?	☺	☺	☺	☺	☺
Qi QQ et al. 2013 [23] c	☺	☺	☺	☺	☺	☺	☺
Qi QQ et al. 2013 [23] c	☺	☺	☺	☺	☺	☺	☺
Kawamura M et al. 2013 [24]	☺	?	?	☺	☺	☺	☺
Liu H et al. 2014 [25]	☺	☺	☺	☺	?	☺	☺

☺Low Risk; ☹High Risk;? Unclear Risk. a, b, c indicate studies identified from one article.