title: Antenatal reflex DNA screening for Down's syndrome using total instead of free B-hCG in the Combined test.
authors.affiliation: Wolfson Institute of Preventive Medicine Barts and the London School of Medicine and Dentistry Queen Mary University of London Charterhouse Square London EC1M 6BQ n.j.wald@qmul.ac.uk.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Wald
authors.affiliation: Wolfson Institute of Preventive Medicine Barts and the London School of Medicine and Dentistry Queen Mary University of London Charterhouse Square London EC1M 6BQ.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Bestwick