Casals 1996.
| Clinical features and settings | High‐risk referral for invasive testing. | |
| Participants | 1138 participants. Spain. 1990‐1993. Pregnant women. 94.4% of women aged > 35 years. Singleton pregnancies. 10‐13 weeks' gestation. |
|
| Study design | Retrospective case‐control study. | |
| Target condition and reference standard(s) | Down's syndrome: 19 cases. Reference standard: CVS. |
|
| Index and comparator tests | Maternal age. Frozen serum samples tested for: First trimester serum free ßhCG (IMx microparticle enzyme immunoassay technology) (19 case and > 80 control samples). First trimester serum AFP (Stratus fluorometric enzyme immunoassay) (19 case and > 80 control samples). First trimester serum PAPP‐A (radioimmunoassay) (only for 16 case and 80 control samples). |
|
| Follow‐up | 100% karyotyping. | |
| Aim of study | To examine the value of ßhCG, AFP and PAPP‐A in biochemical screening for Down's syndrome in 19 women carrying Down's syndrome versus normal pregnancies. | |
| Notes | ||
| Table of Methodological Quality | ||
| Item | Authors' judgement | Description |
| Representative spectrum? All tests | Yes | Selective testing of high‐risk women as done in practice. |
| Acceptable reference standard? All tests | Yes | CVS. |
| Partial verification avoided? All tests | Yes | All women received a reference standard. |
| Differential verification avoided? All tests | Yes | All women had the same reference standard. |
| Incorporation avoided? All tests | Yes | Reference standard was independent of the index test. |
| Reference standard results blinded? All tests | Yes | Reference standard interpreted without knowledge of index test results. |
| Index test results blinded? All tests | Unclear | Unclear if all index test interpreted without knowledge of reference standard results (PAPP‐A testing conducted blind to CVS results but presence of blinding is not stated for free ßhCG and AFP). |
| 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. |