Kagan 2009.
| Clinical features and settings | Routine screening. | |
| Participants | 56,954 participants with available outcome data. UK ‐ multicentre study. July 1999 ‐ April 2007. Pregnant women. Singleton pregnancies. Mean maternal age 35.4 years (14.1‐52.2 years). 11‐13 weeks' gestation. |
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| Study design | Prospective cohort. | |
| Target condition and reference standard(s) | Down's syndrome: 395 cases. Reference standards: karyotyping or follow‐up to birth. |
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| Index and comparator tests | Maternal age. First trimester NT. First trimester fetal heart rate (pulsed‐wave Doppler). First trimester nasal bone (FMF certified sonographers). First trimester ductus venous flow (FMF certified sonographers). First trimester flow across tricuspid valve (FMF certified sonographers). First trimester PAPP‐A and free ßhCG (Kryptor, Brahms AG or Delfia Express, Perkin Elmer). Multiple publications with different test evaluations. |
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| Follow‐up | Karyotype results and details of pregnancy outcome were added to databases as they became available. Women without complete screening and outcome data (n = 3053, 5.1%) were excluded from the study. | |
| Aim of study | To examine the performance of first‐trimester screening for trisomies 21, 18 and 13 by maternal age, fetal NT thickness, fetal heart rate and maternal serum free ß‐hCG and PAPP‐A. Other objectives in related publications. |
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| 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. |