title: Validating whole slide imaging for diagnostic purposes in pathology: guideline from the College of American Pathologists Pathology and Laboratory Quality Center.
abstract: BACKGROUND
  There is increasing interest in using whole slide imaging (WSI) for diagnostic purposes (primary and/or consultation). An important consideration is whether WSI can safely replace conventional light microscopy as the method by which pathologists review histologic sections, cytology slides, and/or hematology slides to render diagnoses. Validation of WSI is crucial to ensure that diagnostic performance based on digitized slides is at least equivalent to that of glass slides and light microscopy. Currently, there are no standard guidelines regarding validation of WSI for diagnostic use.
  
  
  OBJECTIVE
  To recommend validation requirements for WSI systems to be used for diagnostic purposes.
  
  
  METHODS
  The College of American Pathologists Pathology and Laboratory Quality Center convened a nonvendor panel from North America with expertise in digital pathology to develop these validation recommendations. A literature review was performed in which 767 international publications that met search term requirements were identified. Studies outside the scope of this effort and those related solely to technical elements, education, and image analysis were excluded. A total of 27 publications were graded and underwent data extraction for evidence evaluation. Recommendations were derived from the strength of evidence determined from 23 of these published studies, open comment feedback, and expert panel consensus.
  
  
  RESULTS
  Twelve guideline statements were established to help pathology laboratories validate their own WSI systems intended for clinical use. Validation of the entire WSI system, involving pathologists trained to use the system, should be performed in a manner that emulates the laboratory's actual clinical environment. It is recommended that such a validation study include at least 60 routine cases per application, comparing intraobserver diagnostic concordance between digitized and glass slides viewed at least 2 weeks apart. It is important that the validation process confirm that all material present on a glass slide to be scanned is included in the digital image.
  
  
  CONCLUSIONS
  Validation should demonstrate that the WSI system under review produces acceptable digital slides for diagnostic interpretation. The intention of validating WSI systems is to permit the clinical use of this technology in a manner that does not compromise patient care.
authors: From the Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (Drs Pantanowitz, Contis, and Parwani); the Department of Pathology, Yale University School of Medicine, New Haven, Connecticut (Dr Sinard); the Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, Ohio (Dr Henricks); the College of American Pathologists, Northfield, Illinois (Ms Fatheree); the Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia (Dr Carter); the Department of Pathology, North Shore Medical Center, Salem, Massachusetts (Dr Beckwith); the Laboratory Medicine Program, University Health Network, Toronto, Ontario, Canada (Dr Evans); the Department of Pathology, Baystate Medical Center, Tufts University School of Medicine, Springfield, Massachusetts (Dr Otis); and University Hospital, London Health Science Center, London, Ontario, Canada (Dr Lal).
authors: Liron
authors: L
authors: Pantanowitz
authors: John H
authors: JH
authors: Sinard
authors: Walter H
authors: WH
authors: Henricks
authors: Lisa A
authors: LA
authors: Fatheree
authors: Alexis B
authors: AB
authors: Carter
authors: Lydia
authors: L
authors: Contis
authors: Bruce A
authors: BA
authors: Beckwith
authors: Andrew J
authors: AJ
authors: Evans
authors: Avtar
authors: A
authors: Lal
authors: Anil V
authors: AV
authors: Parwani
mesh_terms: D006801:Humans; D003952:Diagnostic Imaging / Q000379:methods / Q000592:standards; D006651:Histocytochemistry / Q000379:methods / Q000592:standards; D007090:Image Interpretation, Computer-Assisted / Q000379:methods / Q000592:standards; D007753:Laboratories; D009656:North America; D015588:Observer Variation; D010338:Pathology, Clinical / Q000379:methods / Q000592:standards; D015203:Reproducibility of Results; D000078202:Systematic Reviews as Topic
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