Table 4.

QUADAS-2 evaluation results

Study	Risk of bias				Applicability concerns
	Patient selection	Index test	Reference standard	Flow and timing	Patient selection	Index test	Reference standard
Study 1	☺	☺	?	☺	☺	☹	?
Study 2	☺	☺	☺	☺	☺	☺	☺
Study 3	☺	☺	☺	☺	☺	☺	☺
Study 4	☺	?	☺	☺	☺	☺	☺
Study 5	☺	?	☺	☺	☺	☺	☺
Study 6	☺	?	☺	☺	☺	☹	☺
Study 7	☺	?	☺	☺	☺	☺	☺

☺, low risk; ☹, high risk; ?, unclear risk