Habayeb 2010.
| Clinical features and settings | Routine screening | |
| Participants | 1507 participants UK ‐ Fetal medicine unit September 2007 ‐ December 2008 Pregnant women Median maternal age 35.4 years (range 18‐49 years) 9‐10, 11‐13 and > 14 weeks' gestation |
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| Study design | Cohort | |
| Target condition and reference standard(s) | Down's syndrome: 12 cases Reference standards: karyotyping or follow‐up to birth |
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| Index and comparator tests | Maternal age Early first trimester PAPP‐A (9 weeks' gestation) (AutoDELFIA PAPP‐A kit, PerkinElmer LAS (UK) Ltd) First trimester NT (11‐13 weeks' gestation) (General Electric E8, Voluson 730 Pro, GE Healthcare) Second trimester AFP, free ßhCG and uE3 (at or after 14 weeks' gestation) (AutoDELFIA(TM) time‐resolved fluoroimmunoassay, PerkinElmer Life Sciences) Second trimester tests given if first trimester risk low (< 1:100) or invasive testing declined Cut‐point for second‐stage risk 1:250 |
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| Follow‐up | Data recorded on a fetal medicine database and combined with data held on separate databases for pregnancy outcome and the regional cytogenetic laboratory. Cytogenetic test results available for all women delivering in the region | |
| Aim of study | To audit a model combining early PAPP‐A with NT and early triple test | |
| 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 | 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 |