Aagaard‐Tillery 2009.
| Clinical features and settings | Routine screening | |
| Participants | 7842 participants who underwent both first and second trimester screening and a second trimester genetic sonogram USA ‐ The First and Second Trimester Evaluation of Risk (FASTER) trial (13 centres) Dates not specified Pregnant women Mean maternal age 30.6 years (SD 6.1 years) Singleton pregnancies 11‐13 and 15‐23 weeks' gestation |
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| Study design | Prospective cohort study | |
| Target condition and reference standard(s) | Down's syndrome: 59 cases Reference standards: karyotyping or follow‐up to birth |
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| Index and comparator tests | Maternal age First trimester NT, PAPP‐A and free ßhCG (details not reported) Second trimester AFP, uE3, free ßhCG and inhibin‐A (details not reported) Second trimester genetic sonogram Detection rate for a 5% false positive rate and for fixed 1:270 cut‐off |
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| Follow‐up | Details of follow‐up not reported | |
| Aim of study | To estimate the effectiveness of second trimester genetic sonography in modifying Down's syndrome screening results | |
| 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 | Yes | Of 33,546 trial participants only 7842 women with complete information for all screening tests and genetic sonography were included in the study |