title: Validation of methodologies for quantifying isolated human islets: an Islet Cell Resources study.
abstract: BACKGROUND
  Quantification of islet mass is a crucial criterion for defining the quality of the islet product ensuring a potent islet transplant when used as a therapeutic intervention for select patients with type I diabetes.
  
  
  METHODS
  This multi-center study involved all eight member institutions of the National Institutes of Health-supported Islet Cell Resources Consortium. The study was designed to validate the standard counting procedure for quantifying isolated, dithizone-stained human islets as a reliable methodology by ascertaining the accuracy, repeatability (intra-observer variability), and intermediate precision (inter-observer variability). The secondary aim of the study was to evaluate a new software-assisted digital image analysis method as a supplement for islet quantification.
  
  
  RESULTS
  The study demonstrated the accuracy, repeatability and intermediate precision of the standard counting procedure for isolated human islets. This study also demonstrated that software-assisted digital image analysis as a supplemental method for islet quantification was more accurate and consistent than the standard manual counting method.
  
  
  CONCLUSIONS
  Standard counting procedures for enumerating isolated stained human islets is a valid methodology, but computer-assisted digital image analysis assessment of islet mass has the added benefit of providing a permanent record of the isolated islet product being evaluated that improves quality assurance operations of current good manufacturing practice.
authors.affiliation: Department of Surgery, Northwestern University, Chicago, IL 60611, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Kissler
authors.forename: J C
authors.initials: JC
authors.lastname: Niland
authors.forename: B
authors.initials: B
authors.lastname: Olack
authors.forename: C
authors.initials: C
authors.lastname: Ricordi
authors.forename: B J
authors.initials: BJ
authors.lastname: Hering
authors.forename: A
authors.initials: A
authors.lastname: Naji
authors.forename: F
authors.initials: F
authors.lastname: Kandeel
authors.forename: J
authors.initials: J
authors.lastname: Oberholzer
authors.forename: L
authors.initials: L
authors.lastname: Fernandez
authors.forename: J
authors.initials: J
authors.lastname: Contreras
authors.forename: T
authors.initials: T
authors.lastname: Stiller
authors.forename: J
authors.initials: J
authors.lastname: Sowinski
authors.forename: D B
authors.initials: DB
authors.lastname: Kaufman
mesh_terms: D002469:Cell Separation / Q000379:methods; D048429:Cell Size; D003697:Delphi Technique; D005434:Flow Cytometry; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007515:Islets of Langerhans / Q000166:cytology*; D016381:Islets of Langerhans Transplantation / Q000379:methods; D015203:Reproducibility of Results