Antenatal screening for Downʹs syndrome with the quadruple test

Second trimester screening for Downʹs syndrome is widely practised throughout the world. We assessed the performance of antenatal serum screening for Downʹs syndrome with the quadruple test in 46 193 pregnancies from 14 hospitals over 5 years. Women who screened positive (risk ≥1 in 300) were offered diagnostic amniocentesis or chorionic villus sampling. Of 88 observed Downʹs syndrome pregnancies, 71 (81%) had a positive screening result (81% detection rate, 95% CI 72–89), and of 46 105 unaffected pregnancies, 3200 tested positive (7% false-positive rate). These results show that the quadruple test is a better method of screening for Downʹs syndrome than use of maternal age alone (51% detection rate, 14% false-positive rate) and is more effective than other second trimester screening tests. Therefore, we conclude that the quadruple test should be the test of choice in second trimester screening for Downʹs syndrome.