title: Is maternal plasma DNA testing impacting serum-based screening for aneuploidy in the United States?
abstract: OBJECTIVE
  We sought to determine whether tests for fetal aneuploidy based on next-generation sequencing of cell-free DNA in maternal circulation have had an impact on routine serum-based screening in the general pregnant population.
  
  
  METHODS
  We compared results from laboratory surveys in 2011 and 2014 that reported types of prenatal serum screening tests and numbers of tests performed. Testing records from two prenatal serum screening laboratories examined temporal trends in the proportion of screened women 35 years of age and older from 2008 (or 2009) to 2014.
  
  
  RESULTS
  The 82 laboratory survey results available for comparison showed that 1.7 million women were screened in 2014, a 5% increase over 2011. In the two screening laboratories, the proportion of screened women age 35 and older increased for several years but then experienced reductions of 8 and 18% by mid-2014 when compared with the highest rates observed.
  
  
  CONCLUSIONS
  As of 2014, maternal plasma DNA testing appears to have had only a minor impact on serum screening rates in the United States. Ongoing surveillance has the potential to determine if, and when, DNA testing begins to replace serum testing as a primary screen for Down syndrome in the United States.
authors.affiliation: Division of Medical Screening and Special Testing, Department of Pathology and Laboratory Medicine, Women & Infants Hospital, Alpert Medical School of Brown University, Providence, Rhode Island, USA.
authors.forename: Glenn E
authors.identifier: http://orcid.org/0000-0001-6154-8449
authors.initials: GE
authors.lastname: Palomaki
authors.affiliation: ARUP Laboratories, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, USA.
authors.forename: Edward R
authors.initials: ER
authors.lastname: Ashwood
authors.affiliation: Department of Pathology, University of South Carolina School of Medicine, Greenville, South Carolina, USA.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Best
authors.affiliation: Division of Medical Screening and Special Testing, Department of Pathology and Laboratory Medicine, Women & Infants Hospital, Alpert Medical School of Brown University, Providence, Rhode Island, USA.
authors.forename: Geralyn
authors.identifier: http://orcid.org/0000-0002-9440-3411
authors.initials: G
authors.lastname: Lambert-Messerlian
authors.affiliation: Division of Medical Screening and Special Testing, Department of Pathology and Laboratory Medicine, Women & Infants Hospital, Alpert Medical School of Brown University, Providence, Rhode Island, USA.
authors.forename: George J
authors.initials: GJ
authors.lastname: Knight
mesh_terms: D000328:Adult; D000782:Aneuploidy; D004247:DNA / Q000097:blood*; D005260:Female; D005820:Genetic Testing; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D008403:Mass Screening; D008875:Middle Aged; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods* / Q000592:standards; D062486:Public Health Surveillance; D015203:Reproducibility of Results; D014481:United States
chemical_list: D004247:DNA