Recommendations for Validating Whole Slide Imaging in Pathology: College of American Pathologists Pathology and Laboratory Quality Center
Liron Pantanowitz, John H. Sinard, Lisa A. Fatheree, Walter H. Henricks, Alexis Byrne Carter, Lydia C. Contis, Bruce A. Beckwith, Andrew John Evans, Christopher N. Otis, James H. MacDonald, Anil Vasdev Parwani · American Journal of Clinical Pathology · 2012
Whole slide imaging (WSI) is increasingly being used for diagnostic purposes, education, and research. Concern has arisen whether WSI can replace the conventional light microscope as the method by which pathologists view patient samples and render a diagnosis (primary and/or consultation). Validation of WSI is important to ensure that digitized slides are at least equivalent to glass slides. There are currently no standardized guidelines regarding validation of WSI for clinical diagnostic use. The CAP Pathology and Laboratory Quality Center convened a nonvendor panel from North America with expertise in digital pathology. Data sources for recommendations were derived from panel consensus and an extensive literature review. For the final selected articles, publication year, author country, WSI clinical application, number of persons and cases used, validation method, and outcome measurement were recorded, analyzed, and graded. Validation of WSI is necessary to ensure that a pathologist using this technique to view digitized glass slides can consistently make the same clinical interpretation as from viewing the glass slides using a traditional bright-field microscope. Validation should address technical and interpretation components, thus demonstrating that the WSI system is capable of producing an acceptable digital slide for interpretation. Approved use of WSI should be limited to the conditions under which validation occurred. A minimum sample size is recommended for a validation study that includes a broad spectrum of specimen types and diagnoses likely to be encountered for the intended clinical use, thereby simulating real-world clinical practice. A pathologist must be involved in the validation process. Measurable outcomes should document diagnostic concordance (accuracy) between digitized and glass slides for the same observer (intraobserver variability) within a reasonable washout period. Our intention is to submit detailed recommendations for public commentary before final publication.