Barrett 2008.
| Clinical features and settings | Routine screening | |
| Participants | 10,273 participants with complete screening and outcome data Australia ‐ screening programme, independent ultrasound practices 24‐month period (dates not specified) Pregnant women Mean maternal age 34.9 years (screen positive) and 30.5 years (screen negative) Singleton pregnancies 11‐13 weeks' gestation |
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| Study design | Cohort study | |
| Target condition and reference standard(s) | Down's syndrome: 32 cases Reference standard: karyotyping or follow‐up to birth |
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| Index and comparator tests | NT (FMF protocol) First trimester PAPP‐A and free ßhCG (90.2% by time resolved amplified cryptate emission technology, Kryptor random access immunoassay analyzer, Brahms, 9.8% by manual Ortho Clinical Diagnostic Immunometric I125 immunoassay for PAPP‐A, and Ortho Clinical Diagnostics Vitros ECi automated analyzer for ßhCG) Risk cut‐off 1:300 |
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| Follow‐up | Linkage to data collected by the Midwives Notification System and the Western Australia Birth Defects Registry and by searching laboratory records of all prenatal cytogenetics services in the state. 162 women lost to follow‐up were excluded Pregnancy loss in 54 women due to miscarriage (n = 35), stillbirth (n = 17) and neonatal death (n = 2) |
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| Aim of study | To investigate associations between combined first‐trimester screen result, pregnancy associated plasma protein level and adverse fetal outcomes in women | |
| 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 |