title: A novel turbidimetric immunoassay for fecal calprotectin optimized for routine chemistry analyzers.
abstract: BACKGROUND
  Fecal calprotectin assays are widely used to exclude inflammatory bowel disease (IBD) in patients with suspected IBD. A problem with the fecal calprotectin assays is the rather long test-turnaround times. A particle enhanced turbidimetric immunoassays (PETIA) for fecal calprotectin would reduce test-turnaround times and would permit more laboratories to perform the measurements. The aim of this study was to evaluate a new feces calprotectin PETIA.
  
  
  METHODS
  Using routine fecal samples the feces calprotectin PETIA was validated on two chemistry analyzers, Mindray BS-380 and Cobas 501.
  
  
  RESULTS
  The assay is linear in the range 11-2000 μg/g, with a limit of quantitation of approximately 10 μg/g. No antigen excess hook effect was observed up to 10 000-15 000 μg/g depending on the instrument used. The turbidimetric method showed a good agreement with the Bühlmann ELISA. The total coefficient of variation was 3%-8% in the 50-100 μg/g range.
  
  
  CONCLUSIONS
  The fecal calprotectin PETIA, fCal Turbo, is well suited for rapid analysis of fecal calprotectin on Mindray BS-380 or Cobas 501 clinical chemistry analyzers. The test results are commutable with Bühlmann fecal MRP8/14 ELISA.
authors.affiliation: Department of Medical Sciences, Uppsala University, Uppsala, Sweden.|Gentian AS, Moss, Norway.
authors.forename: Tom
authors.initials: T
authors.lastname: Nilsen
authors.affiliation: Gentian AS, Moss, Norway.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Sunde
authors.affiliation: Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Lars-Olof
authors.initials: LO
authors.lastname: Hansson
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institute and Clinical Chemistry, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Aleksandra Mandic
authors.initials: AM
authors.lastname: Havelka
authors.affiliation: Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Larsson
mesh_terms: D015415:Biomarkers / Q000032:analysis*; D005243:Feces / Q000737:chemistry*; D006801:Humans; D000074024:Immunoturbidimetry / Q000379:methods*; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis; D039841:Leukocyte L1 Antigen Complex / Q000737:chemistry*; D057230:Limit of Detection; D016014:Linear Models; D015203:Reproducibility of Results
chemical_list: D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex
keywords: biological markers; calprotectin; feces; humans; inflammatory bowel diseases; method validation