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Improvements in antenatal screening for Down's syndrome
N J Wald1, J P Bestwick, W J Huttly
1Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine and Dentistry, Charterhouse Square, London EC1M 6BQ, UK. n.j.wald@qmul.ac.uk
Insights
Adding ductus venosus pulsatility index (DVPI), fetal nasal bone examination (NBE), and placental growth factor (PlGF) significantly improves antenatal screening for Down syndrome. These markers reduce false positives in Combined and Integrated tests, enhancing screening accuracy.
Area of Science:
- Prenatal diagnostics
- Maternal-fetal medicine
- Genetics
Background:
- Antenatal screening for Down syndrome is crucial for early detection.
- Current screening methods have limitations in detection rates and false-positive rates.
- Novel markers are being investigated to improve screening efficacy.
Purpose of the Study:
- To evaluate the impact of adding ductus venosus pulsatility index (DVPI), fetal nasal bone examination (NBE), and serum placental growth factor (PlGF) to existing antenatal screening tests for Down syndrome.
- To compare the performance of enhanced screening protocols.
Main Methods:
- Statistical analysis of data from multiple sources.
- Monte Carlo simulations were employed to model screening performance.
- Data were analyzed using the maternal age distribution of live births in England and Wales (2006-2008).
Main Results:
- Adding DVPI, NBE, and PlGF to the Combined test reduced the false-positive rate (FPR) from 16.1% to 3.0% at a 95% detection rate (DR).
- For the Integrated test, the same additions decreased the FPR from 4.1% to 0.6% at a 95% DR.
- The Integrated test with DVPI, NBE, and PlGF demonstrated superior performance compared to the Combined test with the same markers.
Conclusions:
- The addition of DVPI, NBE, and PlGF significantly enhances the screening performance of Combined and Integrated tests for Down syndrome.
- These markers can reduce false-positive rates by over 80%.
- The enhanced Integrated test offers superior screening accuracy compared to the enhanced Combined test.
Objectives:
To estimate improvements to four antenatal screening tests for Down's syndrome (first trimester Combined, second trimester Quadruple, and first and second trimester Integrated and Serum Integrated tests) based on adding ductus venosus pulsatility index (DVPI), fetal nasal bone examination (NBE) and serum placental growth factor (PlGF).
Setting:
Statistical analysis of data from several sources modelled using the maternal age distribution of live births in England and Wales from 2006 to 2008.
Methods:
Monte Carlo simulation carried out to estimate the screening performance of tests with the addition of combinations of DVPI, NBE and PlGF.
Results:
At a 95% detection rate (DR), with first trimester markers measured at 11 completed weeks' gestation, the addition of DVPI, NBE and PlGF decreased the false-positive rate (FPR) of the Combined test from 16.1% to 3.0%, the addition of PlGF to the Quadruple test decreased the FPR from 15.7% to 15.3%, the addition of DVPI, NBE and PlGF to the Integrated test decreased the FPR from 4.1% to 0.6% and the addition of PlGF to the Serum Integrated test decreased the FPR from 15.1% to 11.1%. At a 90% detection rate, the reductions in the FPR were from 6.8% to 0.8%, 7.7% to 7.4%, 1.2% to 0.1% and 6.2% to 4.8%, respectively.
Conclusions:
The addition of DVPI, NBE and PlGF to the Combined and Integrated tests significantly improves screening performance, reducing the FPRs by over 80%. The Integrated test with DVPI, NBE and PlGF is significantly better than the Combined test with DVPI, NBE and PlGF.
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