title: [Comparison of current methods of prenatal screening for down syndrome].
abstract: BACKGROUND
  In Spain all pregnant women aged 35 years and older are offered genetic examination through invasive testing in order to detect fetal trisomy 21 cases (maternal age indication (MAI)). In the last decade five distinct software programs utilizing the "first trimester screening (FTS)" were developed. The objective of this study is to compare the test performance of the different screening methods in order to detect the best current approach.
  
  
  METHODS
  7.736 complete first trimester screenings, including the fetal outcome, were realized between 31.08.1999 and 24.05.2007 in three prenatal health centres in Hannover, Peine, and Wolfenbüttel in Germany. Out of these 6.508 cases were analyzed retrospectively in this study. Maternal age was determined and risk calculation with the software programs PIA, PRC, JOY, AFS and AFS-3D was executed.
  
  
  RESULTS
  The MAI reached a sensitivity of 57.50%, detecting only 23 out of 40 trisomy 21 cases, and a false positive rate of 21.60%. In comparison, all risk calculation programs obtained superior results, attaining a sensitivity between 90.00% (AFS) and 92.50% (PIA, PRC, JOY, AFS-3D) and a false positive rate between 2.64% (AFS-3D) and 7.87% (PIA). The difference was highly significant (p<0.0001)
  
  
  CONCLUSIONS
  The MAI is obsolete and inadequate in comparison with the risk calculation software, out of which all obtained test performances within the range of comparable international publications. Among these programs, JOY, AFS, and AFS-3D obtained the best results.
authors.affiliation: Departamento de Obstetricia y Ginecología, Universidad de Medicina de Hannover, Hannover, Alemania. cinsanchez@hotmail.com
authors.forename: Cindy
authors.initials: C
authors.lastname: Hörmansdörfer
authors.forename: Alejandro
authors.initials: A
authors.lastname: Corral
authors.forename: Alexander
authors.initials: A
authors.lastname: Scharf
authors.forename: Bernhard
authors.initials: B
authors.lastname: Vaske
authors.forename: Peter
authors.initials: P
authors.lastname: Hillemanns
authors.forename: Peter
authors.initials: P
authors.lastname: Schmidt
mesh_terms: D000782:Aneuploidy; D001499:Bayes Theorem; D003627:Data Interpretation, Statistical; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D005865:Gestational Age; D006801:Humans; D008403:Mass Screening / Q000379:methods; D008423:Maternal Age; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis; D012189:Retrospective Studies; D012307:Risk Factors