Palomaki 2007 FTS.

Clinical features and settings	Routine screening
Participants	10,775 participants Canada ‐ General Hospital October 2003 ‐ November 2004 Pregnant women Mean maternal age 32.3 years (SD 4.6 years) 10‐13 weeks' gestation
Study design	Prospective cohort
Target condition and reference standard(s)	Down's syndrome: 23 cases Reference standards: karyotyping or follow‐up to birth
Index and comparator tests	Maternal age FT NT (encouraged to only accept measurements from sonographers with FMF certification) FT PAPP‐A (AutoDELFIA, PerkinElmer) FT hyperglycosylated‐hCG (Nichols Advantage Specialty system, Nochols Institute Diagnosics)
Follow‐up	From electronic record searches of local patient and cytogenetic records and case finding of local and regional birth records
Aim of study	To validate Down's syndrome screening protocols that include hyperglycosylated‐hCG measurements
Notes
Table of Methodological Quality
Item	Authors' judgement	Description
Representative spectrum? All tests	Yes	Routine screening of typical pregnant population
Acceptable reference standard? All tests	Yes	Karyotyping or follow‐up to birth
Partial verification avoided? All tests	Unclear	Unclear if all women received a reference standard
Differential verification avoided? All tests	No	Choice of reference standard depended on index test results
Incorporation avoided? All tests	Yes	Reference standard was independent of the index test
Reference standard results blinded? All tests	No	Reference standard interpreted with knowledge of index test results
Index test results blinded? All tests	Yes	Index test interpreted without knowledge of reference standard results
Relevant clinical information? All tests	Yes	Information available as would be in standard clinical practice
Uninterpretable results reported? All tests	No	No details given for test failures/uninterpretable measurements
Withdrawals explained? All tests	No	No details of withdrawals given