Validation of multiple whole slide imaging scanners based on the guideline from the College of American Pathologists Pathology and Laboratory Quality Center

Arch Pathol Lab Med. 2015 May;139(5):656-64. doi: 10.5858/arpa.2014-0073-OA.


Context: Whole slide imaging (WSI) produces a virtual image that can be transmitted electronically. This technology has clinical applications in situations in which glass slides are not readily available.

Objective: To examine the results of a validation study performed using the draft version of the WSI clinical validation guideline recently released by the College of American Pathologists.

Design: Ten iScan Coreo Au scanners (Ventana Medical Systems, Tucson, Arizona) were validated, 6 with one set of 100 cases and 4 with a different set of 100 cases, for 1000 case examinations. The cases were selected consecutively from the following case types: internal consultations and malignancies and cases with frozen sections, special stains, and/or immunohistochemistry. Only key slides were scanned from each case. The slides were scanned at ×20 magnification. Pathologists reviewed the cases as both glass slides and WSI, with at least a 3-week washout period between viewings.

Results: Intraobserver agreement between glass slides and WSI was present for 786 (79%) of the 1000 cases. Major discrepancies occurred in 18 cases (1.8%). κ statistics compiled for the subset of cases (n = 504; 50%) with concern for neoplasia showed excellent agreement (κ = 0.8782). Individual scanners performed similarly to one another. Analysis of the results revealed an area of concern: small focal findings.

Conclusions: The results were felt to validate the use of WSI for the intended applications in our multiinstitutional laboratory system, although scans at ×20 magnification may be insufficient for cases hinging on small focal findings, such as microorganisms and inflammatory processes.

Publication types

  • Validation Study

MeSH terms

  • Biopsy
  • Diagnostic Imaging / instrumentation
  • Diagnostic Imaging / methods*
  • Feasibility Studies
  • Female
  • Humans
  • Image Interpretation, Computer-Assisted / methods*
  • Male
  • Microscopy / instrumentation
  • Microscopy / methods
  • Neoplasms / diagnosis*
  • Observer Variation
  • Pathology, Clinical / instrumentation
  • Pathology, Clinical / methods*
  • Pathology, Surgical / instrumentation
  • Pathology, Surgical / methods*
  • Remote Consultation
  • Software
  • Telepathology / instrumentation
  • Telepathology / methods
  • Workflow