title: Author response to letter from Song et al.
authors.affiliation: Ariosa Diagnostics, Inc. , San Jose, CA , USA and.
authors.forename: Ken
authors.initials: K
authors.lastname: Song
authors.forename: Thomas
authors.initials: T
authors.lastname: Musci
authors.forename: Aaron B
authors.initials: AB
authors.lastname: Caughey
mesh_terms: D004314:Down Syndrome / Q000175:diagnosis* / Q000191:economics*; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000191:economics*; D062145:Maternal Serum Screening Tests / Q000191:economics*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000191:economics*; D017422:Sequence Analysis, DNA / Q000191:economics*