title: Diagnosis of Cystic Fibrosis: Consensus Guidelines from the Cystic Fibrosis Foundation.
abstract: OBJECTIVE
  Cystic fibrosis (CF), caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, continues to present diagnostic challenges. Newborn screening and an evolving understanding of CF genetics have prompted a reconsideration of the diagnosis criteria.
  
  
  METHODS
  To improve diagnosis and achieve standardized definitions worldwide, the CF Foundation convened a committee of 32 experts in CF diagnosis from 9 countries to develop clear and actionable consensus guidelines on the diagnosis of CF and to clarify diagnostic criteria and terminology for other disorders associated with CFTR mutations. An a priori threshold of ≥80% affirmative votes was required for acceptance of each recommendation statement.
  
  
  RESULTS
  After reviewing relevant literature, the committee convened to review evidence and cases. Following the conference, consensus statements were developed by an executive subcommittee. The entire consensus committee voted and approved 27 of 28 statements, 7 of which needed revisions and a second round of voting.
  
  
  CONCLUSIONS
  It is recommended that diagnoses associated with CFTR mutations in all individuals, from newborn to adult, be established by evaluation of CFTR function with a sweat chloride test. The latest mutation classifications annotated in the Clinical and Functional Translation of CFTR project (http://www.cftr2.org/index.php) should be used to aid in diagnosis. Newborns with a high immunoreactive trypsinogen level and inconclusive CFTR functional and genetic testing may be designated CFTR-related metabolic syndrome or CF screen positive, inconclusive diagnosis; these terms are now merged and equivalent, and CFTR-related metabolic syndrome/CF screen positive, inconclusive diagnosis may be used. International Statistical Classification of Diseases and Related Health Problems, 10th Revision codes for use in diagnoses associated with CFTR mutations are included.
authors.affiliation: Departments of Pediatrics and Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Farrell
authors.affiliation: Cystic Fibrosis Foundation, Bethesda, MD.
authors.forename: Terry B
authors.initials: TB
authors.lastname: White
authors.affiliation: Section of Pediatric Pulmonology, Allergy, and Sleep Medicine, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, IN.
authors.forename: Clement L
authors.initials: CL
authors.lastname: Ren
authors.affiliation: Cystic Fibrosis Foundation, Bethesda, MD.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Hempstead
authors.affiliation: Section of Pediatric Pulmonology, Colorado School of Public Health, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO.
authors.forename: Frank
authors.initials: F
authors.lastname: Accurso
authors.affiliation: CFTR Biomarker Center and Translational CF Research Group, CF Center, Pediatric Pulmonology and Immunology, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Nico
authors.initials: N
authors.lastname: Derichs
authors.affiliation: Section of Pediatric Pulmonology, Allergy, and Sleep Medicine, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, IN.
authors.forename: Michelle
authors.initials: M
authors.lastname: Howenstine
authors.affiliation: Department of Pediatrics, Northwestern University Feinberg School of Medicine, and Division of Pulmonary Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL.
authors.forename: Susanna A
authors.initials: SA
authors.lastname: McColley
authors.affiliation: Departments of Pediatrics and Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Michael
authors.initials: M
authors.lastname: Rock
authors.affiliation: Seattle Children's Research Institute and Department of Pediatrics, University of Washington School of Medicine, Seattle, WA.
authors.forename: Margaret
authors.initials: M
authors.lastname: Rosenfeld
authors.affiliation: Centres de Ressources et de Compétences pour la Mucoviscidose, Institut Necker Enfants Malades/INSERM U1151, Hôpital Necker Enfants Malades, Paris, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Sermet-Gaudelus
authors.affiliation: Department of Women's and Children's Health, University of Liverpool, Institute in the Park, Alder Hey Children's Hospital, Liverpool, United Kingdom.
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Southern
authors.affiliation: Cystic Fibrosis Foundation, Bethesda, MD.
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Marshall
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University, Baltimore, MD.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Sosnay
mesh_terms: D003550:Cystic Fibrosis / Q000175:diagnosis*; D006801:Humans; D007231:Infant, Newborn; D015997:Neonatal Screening; D000073718:Pancreatitis-Associated Proteins
keywords: CF-screen positive, inconclusive diagnosis; CFTR-related metabolic syndrome; immunoreactive trypsinogen; intestinal current measurement; nasal potential difference; newborn screening; pancreatitis associated protein; sweat test