College of American Pathologists

Validating Whole Slide Imaging for Diagnostic Purposes
in Pathology

Guideline from the College of American Pathologists: Pathology and Laboratory Quality Center


Updated July 14, 2014


The CAP’s evidence-based guideline, “Validating Whole Slide Imaging for Diagnostic Purposes in Pathology,” serves as a practical guide for pathologists and laboratories to confirm the accuracy and concordance of their own WSI systems for diagnostic work while ensuring the digital tool is being used properly for its intended clinical use.

The panel addressed the key question of “What should be done to validate a whole slide digital imaging system for diagnostic purposes before it is placed in clinical service?” and developed twelve practical recommendations, including these key points:

  • Validation of the entire WSI system, involving pathologists trained to use the system, should be performed in a manner which emulates the laboratory’s actual clinical environment.
  • It is recommended that such a validation study include at least 60 routine cases per application, comparing intra-observer diagnosis concordance between digitized and glass slides viewed at least two weeks apart.
  • It is important that the validation process confirms that all material present on a glass slide to be scanned is included in the digital image.

Currently, the US Food and Drug Administration does not approve WSI systems for primary diagnosis. In that context, this CAP guideline gives current recommendations while preparing its members for wider adoption of digital imaging technology in the future. Pathologists practicing abroad can begin to implement the guideline immediately in concordance with their country’s regulatory guidelines for using WSI in making primary diagnoses.

Guideline and Supplemental Digital Content Guideline and Supplemental Digital Content

Validating Whole Slide Imaging for Diagnostic Purposes in Pathology

Detailed information regarding the project’s comprehensive literature review, evidence grading and conflict of interest policy, etc., may be accessed in the Supplemental Digital Content available online within the manuscript.

Resources Resources

Summary of Recommendations
(PDF, 224 KB)

CAP Digital Pathology Guideline Overview and Discussion
May 17, 2013
Access Presentation Slides from Webinar

Teaching Presentation
(PDF, 440 KB)
Download the recommendations with background evidence information

Frequently Asked Questions
(PDF, 68 KB)

CAP Digital Pathology Resource Guide
(PDF, 1 MB)
Prepared by the CAP and intended for Pathologists who are considering or actively planning to adopt digital pathology technology in their practice

Chapter 7 from CAP eBook: New Paths...New Choices: Pathology in an Era of Advancing Science and Disruptive Health Economics
Digital Pathology: New Technology Breaks the Distance Barrier

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