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 whole slide imaging (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 intraobserver 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.