Search

Objective To evaluate the impact of the introduction of a Down syndrome screening policy in England, including implementation of the first-trimester combined screening test, on reducing prenatal invasive diagnostic procedure rates. Methods All English cytogenetic laboratories were asked to submit data from the fiscal years 2003/2004 until 2011/2012 on all samples received from prenatal invasive procedures, including those that were undertaken following a higher-risk Down syndrome screening result. Results There was a gradual decline in the number of invasive procedures undertaken subsequent to a positive Down syndrome screening result in England, from 36?968 in 2003/2004 to 11?446 in 2008/2009, with only a relatively small subsequent decrease, to 10?215, in 2011/2012. This corresponds to a 72% reduction in the number of referrals received by the cytogenetic laboratories over a 9-year period and correlates with the national policy of implementing the combined screening test in place of second-trimester screening, which has reduced the overall screen-positive rate to 3.1% from an initial level of 6.0%. Conclusions Implementation of a national Down syndrome screening policy based on the combined screening test has significantly reduced the number of invasive tests performed. However, as the combined screening test has become the replacement for second-trimester testing and has been almost completely implemented it appears that improvements in screening using current approaches may have reached their limits. [ABSTRACT FROM AUTHOR]

We carried out an audit of antenatal screening for Down's syndrome using the Integrated test (which provides a single screening result from information collected in the late first and early second trimesters of pregnancy) which was introduced into routine antenatal care at two London hospitals, University College Hospital (UCH) and St Mary's Hospital, in 2003-4. The audit was based on 15,888 women who accepted screening and booked in the first trimester. The Down's syndrome detection rate was 87% (95% confidence interval [CI], 74-95) consistent with an expected detection rate of 89% based on applying the estimates of screening performance of the Serum, Urine and Ultrasound Screening Study (SURUSS) to the maternal age distribution of women who were screened at UCH and St Mary's. The observed false-positive rate was 2.1% (95% CI, 1.9-2.3), compared with an expected of 2.5% for women of the same age. An audit trail (conducted at UCH) indicated that 98% (10,746/10,961) of women accepted integrated screening (2% having a first trimester test) and of these, 94% (10,116) completed both stages of the test. The audit demonstrated that it is feasible to conduct integrated screening within the NHS with a high acceptance rate and a screening performance consistent with that determined from previous research studies. [ABSTRACT FROM AUTHOR]