title: Diagnosis of Cystic Fibrosis in Screened Populations.
abstract: Cystic fibrosis (CF) can be difficult to diagnose, even when newborn screening (NBS) tests yield positive results. This challenge is exacerbated by the multitude of NBS protocols, misunderstandings about screening vs diagnostic tests, and the lack of guidelines for presumptive diagnoses. There is also confusion regarding the designation of age at diagnosis.
  
  
  
  To improve diagnosis and achieve standardization in definitions worldwide, the CF Foundation convened a committee of 32 experts with a mission to develop clear and actionable consensus guidelines on diagnosis of CF with an emphasis on screened populations, especially the newborn population. A comprehensive literature review was performed with emphasis on relevant articles published during the past decade.
  
  
  
  After reviewing the common screening protocols and outcome scenarios, 14 of 27 consensus statements were drafted that apply to screened populations. These were approved by 80% or more of the participants.
  
  
  
  It is recommended that all diagnoses be established by demonstrating dysfunction of the CF transmembrane conductance regulator (CFTR) channel, initially with a sweat chloride test and, when needed, potentially with newer methods assessing membrane transport directly, such as intestinal current measurements. Even in babies with 2 CF-causing mutations detected via NBS, diagnosis must be confirmed by demonstrating CFTR dysfunction. The committee also recommends that the latest classifications identified in the Clinical and Functional Translation of CFTR project [http://www.cftr2.org/index.php] should be used to aid with CF diagnosis. Finally, to avoid delays in treatment, we provide guidelines for presumptive diagnoses and recommend how to determine the age of diagnosis.
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: Michelle S
authors.initials: MS
authors.lastname: Howenstine
authors.affiliation: Centres de Ressources et de Compétences pour la Mucoviscidose, Hôpital Robert Debre, Paris, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Munck
authors.affiliation: Department of Pediatric and Newborn Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, MA.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Parad
authors.affiliation: Department of Pediatrics, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA.
authors.forename: Margaret
authors.initials: M
authors.lastname: Rosenfeld
authors.affiliation: Heidelberg Cystic Fibrosis Center, Heidelberg, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Sommerburg
authors.affiliation: Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, CO.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Accurso
authors.affiliation: Pediatric Respirology and Experimental Medicine, Imperial College London and Pediatric Respiratory Medicine, Royal Brompton and Harefield National Health Service Foundation Trust, London, United Kingdom.
authors.forename: Jane C
authors.initials: JC
authors.lastname: Davies
authors.affiliation: Departments of Pediatrics and Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rock
authors.affiliation: Department of Pediatrics, Section of Pediatric Pulmonology, Allergy and Sleep Medicine, Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, IN.
authors.forename: Don B
authors.initials: DB
authors.lastname: Sanders
authors.affiliation: Pediatric Gastroenterology, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Wilschanski
authors.affiliation: Institut Necker Enfants Malades/INSERM U1151, Hôpital Necker Enfants Malades, Centres de Ressources et de Compétences pour la Mucoviscidose, Paris, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Sermet-Gaudelus
authors.affiliation: Sackler Faculty of Medicine, Graub Cystic Fibrosis Center, Pulmonary Institute Schneider Children's Medical Center of Israel, Petah Tikva, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Hannah
authors.initials: H
authors.lastname: Blau
authors.affiliation: Hospital Vall d'Hebron, Barcelona, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Gartner
authors.affiliation: Ann and Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL.
authors.forename: Susanna A
authors.initials: SA
authors.lastname: McColley
mesh_terms: D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000235:genetics; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D005820:Genetic Testing; D006801:Humans; D007231:Infant, Newborn; D009154:Mutation; D015997:Neonatal Screening; D000073718:Pancreatitis-Associated Proteins; D017410:Practice Guidelines as Topic
chemical_list: D000073718:Pancreatitis-Associated Proteins; C000612141:REG3A protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator
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