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