Herman 2002.

Clinical features and settings	Routine screening
Participants	531 participants: 23 cases and 508 consecutive controls Israel ‐ Medical centre Pregnant women 10‐14 and 16‐19 weeks' gestation
Study design	Case‐control
Target condition and reference standard(s)	Down's syndrome: 23 cases Reference standard: karyotyping or follow‐up to birth
Index and comparator tests	Maternal age First trimester NT () Second trimester AFP, hCG and uE3 ()
Follow‐up	Some cases obtained through follow‐up to birth. No details of follow‐up in controls reported
Aim of study	To compare the results of the disclosure and non‐disclosure approaches, using the clinical data of first trimester ultrasound and second trimester serum screening tests among the same groups of normal and trisomy 21‐affected pregnancies
Test characteristics
Reference standard used
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	Yes	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