Hafner 1998.
| Clinical features and settings | Routine screening | |
| Participants | 4233 participants Austria ‐ single hospital June 1993 to July 1996 Pregnant women Median age 28 years (15‐49 years), 6.9% ≥ 35 years 10‐13 weeks' gestation |
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| Study design | Prospective cohort | |
| Target condition and reference standard(s) | Down’s syndrome: 7 cases Reference standards: amniocentesis or CVS in patients with previous Down’s pregnancy, > 35 years or with a positive biochemical test result. Other women underwent scan at 22 weeks and, if NT > 2.5 mm special examination directed to examination of fetal heart. Follow‐up to birth |
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| Index and comparator tests | First trimester NT (cut‐off 2.5 mm) NT taken in saggital section. Distance between the end of the echogenic muscles of the c spine and the inner layer of echogenic skin with callipers on the line |
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| Follow‐up | No details given of methods of follow‐up. 138 women lost to follow‐up | |
| Aim of study | To determine the value of NT measurement for the detection of aneuploidies and other malformations in a low‐risk population | |
| Notes | It appears that Down’s syndrome was only picked up in cases where CVS or amniocentesis had been conducted and it s not clear if patients were followed up to birth | |
| Table of Methodological Quality | ||
| Item | Authors' judgement | Description |
| Representative spectrum? All tests | Yes | Routine screening of typical pregnant population |
| Acceptable reference standard? All tests | Unclear | Amniocentesis or anomalies scan at 22 weeks. Unclear if women were also followed 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 | Yes | NT measurement was not possible in 2% of cases |
| Withdrawals explained? All tests | No | No details of withdrawals given |