CAP Launches Update to Whole Slide Imaging (WSI) Guideline

Northfield, Ill.— As clinical applications for whole slide imaging and digital pathology rapidly advance, the College of American Pathologists (CAP), in collaboration with the American Society for Clinical Pathology (ASCP) and the Association for Pathology Informatics (API), has updated the guideline “Validating Whole Slide Imaging for Diagnostic Purposes in Pathology,” published today as an early online release in Archives of Pathology & Laboratory Medicine.

Since publication of the original 2013 guideline, the US Food and Drug Administration has approved select digital WSI systems for primary diagnoses in surgical pathology, ushering in new applications for digital pathology but also underscoring the value of the updated guidance and the need to conduct validation before diagnoses are made using WSI.

“Validation of WSI systems is crucial to ensure the quality and consistency of diagnostic performance as an alternative to light microscopy,” said chair for the guideline update, Andrew J. Evans, MD, PhD, FCAP.  “For patients, this could mean receiving their pathologic diagnosis more quickly with the same quality test results and thereby possibly receiving treatment sooner.” 

Dr. Evans led an expert panel of pathologists, histotechnologists, and a methodologist in the systematic reviewed of nearly 1,400 titles and abstracts, 163 manuscripts, and extracted data from 62 studies to update the guideline, following standards established by the National Academies of Medicine.

The updated guideline reaffirms most of the original recommendations but differs in two ways.

First, ASCP and API collaborated on the update, which expanded the reach for the guideline open comment period.  Second, the CAP recently adopted the globally recognized evaluation method known as GRADE, for Grading of Recommendations Assessment, Development and Evaluation, which impacts both the strength and number of recommendations.

As a result, the update provides three strong recommendations that reaffirm the original findings on the validation process, case concordance levels, and washout period. 

Additionally, the update reaffirms nine additional recommendation statements from the 2013 guideline, but using GRADE, now describes them as “good practice statements,” which indicates a high level of certainty, but a lack of direct, published evidence.

The CAP and collaborating societies encourage members to adopt the guideline recommendations. Pathologists and their colleagues should discuss the recommendations to coordinate efforts to implement them. Resources to support guideline adoption are published on cap.org as part of guideline launch.

About the College of American Pathologists

As the world’s largest organization of board-certified pathologists and leading provider of laboratory accreditation and proficiency testing programs, the College of American Pathologists (CAP) serves patients, pathologists, and the public by fostering and advocating excellence in the practice of pathology and laboratory medicine worldwide. For more information, READ THE CAP ANNUAL REPORT at CAP.ORG.