Wapner 2003.
| Clinical features and settings | Routine screening | |
| Participants | 8216 participants USA multicentre study (12 prenatal diagnostic centres) Dates not specified Singleton pregnancies Pregnant women Mean age 35 years (SD 4.6), 50% ≥ 35 years 11 to 14 weeks' gestation |
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| Study design | Prospective cohort | |
| Target condition and reference standard(s) | Down's syndrome: 61 cases Reference standards: invasive testing. Miscarriage with cytogenetic testing. Follow‐up to birth |
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| Index and comparator tests | Maternal age First trimester NT (FMF methods) Dried blood samples tested for: First trimester free ßhCG and PAPP‐A (dried blood samples, enzyme‐linked immunoadsorbent assay as previously described) Risk cut‐point 1:270 |
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| Follow‐up | Follow‐up to birth by directly following up women and reviewing delivery records. An effort was also made to obtain information on terminated or miscarried pregnancies. 196 (2.3%) of patients without follow‐up information were excluded and women with a previous trisomy 18 or 21 pregnancy were also excluded | |
| Aim of study | To evaluate the use of combined first trimester markers for aneuploidy in clinical practice | |
| Notes | 16 live Down’s syndrome births | |
| 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 |