Marsk 2006.
| Clinical features and settings | Routine screening | |
| Participants | 139 participants: 31 cases and 108 controls (3:1 with cases, matched for time of study, geographic location and to be within 5‐year age interval) Sweden ‐ data from Swedish Nuchal Translucency Trial Dates not reported Pregnant women Mean age cases 38.5 years (SD 4.0 years) and controls 35.5 years (SD 4.0 years) Singleton pregnancies 8‐14 weeks' gestation |
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| Study design | Case‐control study | |
| Target condition and reference standard(s) | Down's syndrome: 31 cases Reference standards: not reported |
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| Index and comparator tests | Maternal age First trimester NT (12‐14 weeks) (method not specified) Frozen serum samples PAPP‐A and free ßhCG in sample taken at 8‐14 weeks (Auto Delfia Instrument) Risk cut‐points of 1:250 and 1:350 (Lifecycle software used to calculate risk) |
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| Follow‐up | No details of methods used to follow women‐up | |
| Aim of study | To determine to what extent adding first trimester serum screening to NT would change the detection rate and test positive rate for Down's syndrome | |
| Notes | Part of NUPP trial | |
| 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 | 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 | Yes | Details given for women who did not agree to take part |