Summary of the impact

Pregnant women and public health service providers have benefitted since 2003 from the development of an ultra-sensitive immunoassay for inhibin-A — a hormone that is produced by the placenta during pregnancy and that is elevated in Down's syndrome pregnancies. The assay, developed by Professor Groome at Oxford Brookes University and Professor Knight at the University of Reading in 1994, was the first test capable of quantifying low levels of inhibin-A in the peripheral blood of humans. Addition of this test to existing antenatal screening tests improved the Down's syndrome detection rate from 59% to 70% and from 67% to 77% when combined with ultrasound imaging. Addition of inhibin-A as the fourth marker measured in the maternal blood serum became known as the quadruple or quad test and was adopted into UK clinical guidelines in 2003. It remains the recommended screening test for women who present themselves in the 2^nd trimester. Since 2008 hundreds of thousands of UK women and their healthcare providers have benefitted from the additional information provided by this more accurate screening method, including whether more invasive diagnostic tests are wanted. The quadruple test has been widely adopted in the clinical guidelines in other countries including the US, Canada, and Australia.