Koster 2011.
| Clinical features and settings | Routine screening | |
| Participants | 998 participants: 151 cases and 847 controls matched for gestational age, maternal weight, maternal age and storage time The Netherlands ‐ National institute for Public Health and the Environment 2004 ‐ 2006 Pregnant women Singleton pregnancies Median maternal age 37 years (interquartile range 36‐39 years) 8‐13 weeks' gestation |
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| Study design | Case‐control study | |
| Target condition and reference standard(s) | Down's syndrome: 151 cases Reference standards: karyotyping or follow‐up to birth |
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| Index and comparator tests | Maternal age First trimester NT Fresh serum samples tested for: First trimester free ßhCG and PAPP‐A (AutoDELFIA, PerkinElmer) Frozen serum samples tested for: First trimester ADAM 12s, total hCG, placental protein 13 (PP13) and placental growth factor (PlGF) (AutoDELFIA or DelfiaXpress, PerkinElmer) |
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| Follow‐up | Pregnancy outcome was recorded via questionnaires and self‐reporting by the participating women. Only samples for pregnancies with known outcome were selected as controls | |
| Aim of study | To evaluate the modelled predictive value of 3 current screening markers (PAPP‐A, free ßhCG and NT) and 4 potential screening markers (ADAM 12, total hCG, PP13 and PIGF) for Down's syndrome using different screening strategies | |
| 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 some index test results |
| Index test results blinded? All tests | Unclear | Unclear if all index tests 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 |