title: Newborn screening for cystic fibrosis in Switzerland--consequences after analysis of a 4 months pilot study.
abstract: BACKGROUND
  Switzerland introduced newborn screening (NBS) for CF in 2011, using an IRT/DNA/IRT protocol. This paper describes the results of the first year and compares two versions of the protocol with different IRT cut-offs, particularly effects on recall rate, sensitivity and specificity.
  
  
  METHODS
  IRT cut-offs were >45 ng/ml (99.0th percentile) in period 1 (months 1-4) and >50 ng/ml (99.2nd percentile) in period 2 (months 5-12). In period 2 we abstained from recalls when none of the 7 most common CF mutations were detected and IRT was <60 ng/ml.
  
  
  RESULTS
  In periods 1 and 2, 26,535 and 56,663 tests were performed. Recall rates were 0.94% and 0.48%, respectively (p<0.001), PPV increased from 23% to 47% (p=0.024) and sensitivity was 90% and 100%.
  
  
  CONCLUSIONS
  Raising initial IRT cut-off from the 99.0th to the 99.2nd percentile and abstaining from recalls for children with an IRT<60 ng/ml and carrying no major CFTR mutation significantly reduced the recall rate without affecting sensitivity.
authors.affiliation: Swiss Newborn Screening Laboratory, University Children's Hospital, Zürich, Switzerland.
authors.forename: Toni
authors.initials: T
authors.lastname: Torresani
authors.forename: Ralph
authors.initials: R
authors.lastname: Fingerhut
authors.forename: Corina S
authors.initials: CS
authors.lastname: Rueegg
authors.forename: Sabina
authors.initials: S
authors.lastname: Gallati
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Kuehni
authors.forename: Matthias R
authors.initials: MR
authors.lastname: Baumgartner
authors.forename: Juerg
authors.initials: J
authors.lastname: Barben
mesh_terms: D000465:Algorithms; D003550:Cystic Fibrosis / Q000235:genetics / Q000517:prevention & control*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D004252:DNA Mutational Analysis; D006801:Humans; D007231:Infant, Newborn; D015997:Neonatal Screening; D010865:Pilot Projects; D012680:Sensitivity and Specificity; D013542:Sweat / Q000737:chemistry; D013557:Switzerland; D014362:Trypsinogen / Q000097:blood*
chemical_list: C505032:CFTR protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D014362:Trypsinogen
keywords: Cystic fibrosis; Immunoreactive trypsinogen; Newborn screening; Recall rate