Scott 2004.
| Clinical features and settings | Routine screening. | |
| Participants | 2053 participants. Australia ‐ Private practice (Sydney Ultrasound for Women). July 2000 to May 2002. Pregnant women 15‐44 years (median 32 years). Singleton pregnancies. 11‐14 weeks' gestation. |
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| Study design | Prospective cohort study. | |
| Target condition and reference standard(s) | Down’s syndrome: 5 cases. Reference standards: invasive testing or follow‐up to birth. |
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| Index and comparator tests | Maternal age. First trimester NT (FMF methods, sagittal plane, ATL 5000; Philips). First trimester free ßhCG and PAPP‐A (kryptor analyser, Brahms Diagnostics). All participants had all tests. Risk cut‐point 1:300. |
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| Follow‐up | Data obtained from referring doctors or patients via letter, phone or completed feedback form given at the time of consultation. Only cases of known outcome included in the study. 68 (1.3%) lost to follow‐up, largely due to miscarriage (n = 20) and loss to follow‐up (n = 40). | |
| Aim of study | To report the sensitivity of combined first trimester biochemistry and ultrasound screening for Down's syndrome in an Australian private practice specialising in obstetric ultrasound. | |
| Notes | Only women having biochemical testing before NT were included in the study. This was done to avoid bias from women declining biochemical testing following negative NT. | |
| 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 | Yes | No details of withdrawals given. |