title: The role, yield and cost of paediatric faecal elastase-1 testing.
abstract: OBJECTIVE
  Faecal elastase-1 (FE1) is a sensitive marker for exocrine pancreatic enzyme insufficiency. Pancreatic insufficiency (EPI) leads to maldigestion and subsequent poor weight gain. Thus, FE1 is performed as work-up for children with failure to thrive (FTT). However, EPI in the paediatric population outside of cystic fibrosis (CF) is rare. This study aimed to identify the indications for FE1 testing and their diagnostic yield in children. The secondary aim was to evaluate the cost per case of EPI detected for the various indications.
  
  
  METHODS
  All FE1 tests performed on children (0-18 years) at a tertiary paediatric hospital in Sydney, Australia between 2010 and 2013 (inclusive) were identified. A retrospective chart audit was performed to identify the indication for testing FE1. The diagnostic yield based on FE1 cut-offs <200 and < 100 μg/g were assessed.
  
  
  RESULTS
  The most common indication for testing FE1 was "FTT only" (71/216, 32.9%), however, in this cohort of patients, FE1 was least likely to be positive with only 2 out of the 71 (2.8%) patients returning a positive result. In comparison, CF was the second most common indication for testing (60/216, 27.8%), but nearly half (48.8%) of tests returned a positive result in this cohort. The cost per case detected (FE1 <200 μg/g) reflected the test yield with an average cost per positive test of $262.50 (AUD2015) for FTT with short-gut syndrome and $420.00 (AUD2015) for CF-related indications.
  
  
  CONCLUSIONS
  Our study shows that for patients with isolated failure to thrive, FE1 testing is low yield and costly.
authors.affiliation: Sydney Children's Hospital Randwick, Sydney, Australia.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Williams
authors.affiliation: Department of Clinical Chemistry, South Eastern Area Laboratory Services, Randwick 2031, Australia.
authors.forename: Mary
authors.initials: M
authors.lastname: Moriatis
authors.affiliation: Centre for Big Data Research in Health and the School of Women's and Children's Health, The University of New South Wales, Sydney NSW, Australia.
authors.forename: Georgina M
authors.initials: GM
authors.lastname: Chambers
authors.affiliation: Sydney Children's Hospital Randwick, Sydney, Australia; Discipline of Paediatrics, School of Women's and Children's Health, Medicine, University of New South Wales, Sydney, Australia. Electronic address: keith.ooi@unsw.edu.au.
authors.forename: Chee Y
authors.initials: CY
authors.lastname: Ooi
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003365:Costs and Cost Analysis; D003550:Cystic Fibrosis / Q000175:diagnosis / Q000191:economics / Q000201:enzymology; D003967:Diarrhea / Q000175:diagnosis / Q000209:etiology; D010188:Exocrine Pancreatic Insufficiency / Q000175:diagnosis* / Q000191:economics; D005183:Failure to Thrive; D005243:Feces / Q000201:enzymology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010196:Pancreatic Elastase / Q000032:analysis* / Q000172:deficiency*; D010195:Pancreatitis / Q000175:diagnosis / Q000209:etiology; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012778:Short Bowel Syndrome / Q000175:diagnosis / Q000191:economics
chemical_list: D010196:Pancreatic Elastase
keywords: Cystic fibrosis; Diarrhoea; Failure-to-thrive; Pancreatic insufficiency; Pancreatic sufficiency; Short-gut syndrome