Table 1.

QUADAS Methodological appraisal of single-question studies

Study ID	Representative spectrum?	Reference standard acceptable?	Acceptable delay between tests?	Partial verification avoided?	Differential verification avoided?	Incorporation avoided?	Ref standard blinded?	Index test blinded?	Relevant clinical information	Uninterpretable results reported?	Withdrawals explained?
Single-question studies
Bradley et al, 200149	Unclear	Yes	Yes	Unclear	Yes	No	Yes	Unclear	Yes	No	Yes
Brown et al, 200150	Yes	Yes	Yes	Yes	Yes	No	Unclear	Unclear	Yes	No	No
Fleming et al, 199147	Yes	Yes	Yes	Yes	Yes	No	Unclear	Unclear	Yes	No	No
Seale et al, 200651	Unclear	Yes	Yes	Yes	Yes	Yes	Yes	Unclear	Yes	No	No
Smith et al, 200952	Unclear	Yes	Unclear	Yes	Yes	Yes	No	Unclear	Unclear	No	Yes
Volk, et al, 199747	Yes	Yes	Yes	Yes	Yes	No	Unclear	Unclear	Unclear	No	Unclear
Two-question studies
Brown et al, 200150	Yes	Yes	Yes	Yes	Yes	No	Unclear	Unclear	Yes	No	No
Vinson et al, 200739	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Unclear	Yes	No	No