title: Increased Y-chromosome detection by SRY duplexing.
abstract: OBJECTIVE
  Determining fetal sex noninvasively is dependent of a robust assay. We designed a novel SRY assay and combined it with a SRY assay from literature forming a duplex assay with the same fluorescent dye to increase detection of Y-chromosome at low cell-free fetal DNA or chimeric DNA concentrations.
  
  
  METHODS
  We analyzed 48 plasma samples from pregnant women in gestational weeks 5-35. Fetal sex was determined by DYS14 and SRY. We also compared 2 monoplex SRY assays with a SRY duplex assay at low DNA concentrations.
  
  
  RESULTS
  The DYS14 assay was more sensitive than the SRY assay, but less specific at low cell-free fetal DNA concentrations. We obtained a more sensitive duplex SRY assay with the same specificity as the 2 monoplex assays.
  
  
  CONCLUSIONS
  The SRY duplex assay improves the SRY detection at low DNA concentration.
authors.affiliation: Department of Clinical Immunology, Copenhagen University Hospital, Copenhagen, Denmark. morten.hoegh.hansen@gmail.com
authors.forename: Morten Høgh
authors.initials: MH
authors.lastname: Hansen
authors.forename: Frederik Banch
authors.initials: FB
authors.lastname: Clausen
authors.forename: Morten Hanefeld
authors.initials: MH
authors.lastname: Dziegiel
mesh_terms: D041322:Chromosomes, Human, Y; D004247:DNA / Q000097:blood*; D003718:Denmark; D005260:Female; D005456:Fluorescent Dyes; D024282:Genes, sry; D005865:Gestational Age; D006801:Humans; D008297:Male; D015341:Nucleic Acid Probes; D011237:Predictive Value of Tests; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D012732:Sex Determination Analysis / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes; D015341:Nucleic Acid Probes; D004247:DNA