title: Use of fecal elastase-1 to classify pancreatic status in patients with cystic fibrosis.
abstract: OBJECTIVE
  To test the hypothesis that some patients with cystic fibrosis (CF) are misclassified as pancreatic insufficient, using fecal elastase-1 (FE-1) to define pancreatic status.
  
  
  METHODS
  Subjects with CF at 33 CF centers filled out questionnaires and submitted a stool specimen that was analyzed for FE-1. Subjects taking pancreatic enzyme supplements (PES) were asked to discontinue them and perform a 3-day fecal fat balance study if their FE-1 was >200 microg/g stool and they had never had pancreatitis.
  
  
  RESULTS
  The median value for FE-1 in 1215 subjects was 0 microg/g stool (range, 0-867). There was a significant difference between patients who had been prescribed PES (n=1131) and those who had FE-1 <200 microg/g stool (n=1074; P<.0001). Sixty-seven subjects met criteria for discontinuation of PES. The mean coefficient of fat absorption for these subjects was 96.1%.
  
  
  CONCLUSIONS
  FE-1 is an accurate, easily obtained screening test to classify pancreatic status in patients with CF. This information is important for prognostication, treatment, and to avoid misclassification in clinical research. Measurement of FE-1 should become a standard of care for patients with CF.
authors.affiliation: Department of Pediatrics, Women and Children's Hospital of Buffalo, State University of New York at Buffalo, 219 Bryant Street, Buffalo, NY 14222, USA. dborowitz@upa.chob.edu
authors.forename: Drucy
authors.initials: D
authors.lastname: Borowitz
authors.forename: Susan S
authors.initials: SS
authors.lastname: Baker
authors.forename: Linda
authors.initials: L
authors.lastname: Duffy
authors.forename: Robert D
authors.initials: RD
authors.lastname: Baker
authors.forename: Laura
authors.initials: L
authors.lastname: Fitzpatrick
authors.forename: Joyce
authors.initials: J
authors.lastname: Gyamfi
authors.forename: Kerry
authors.initials: K
authors.lastname: Jarembek
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D010188:Exocrine Pancreatic Insufficiency / Q000145:classification / Q000201:enzymology* / Q000209:etiology; D005243:Feces / Q000201:enzymology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010196:Pancreatic Elastase / Q000302:isolation & purification / Q000378:metabolism*; D012042:Registries
chemical_list: C505032:CFTR protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D010196:Pancreatic Elastase