Implementation of a Canadian External Quality Assurance Program for Breast Cancer Biomarkers: An Initiative of Canadian Quality Control in Immunohistochemistry (cIQc) and Canadian Association of Pathologists (CAP) National Standards Committee/Immunohistochemistry
J Terry, BC Gilks, J Garratt, EE Torlakovic. Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada; College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
Background: Immunohistochemistry (IHC) results for ER, PR, and HER2 are used to guide breast carcinoma patient management. To obtain fewest false-positive or false-negative results, it is essential to monitor laboratory performance through participation in external quality assurance (EQA) programs. Canadian Immunohistochemistry Quality Control (cIQc, www.ciqc.ca) is the first web-based independent EQA program for Canadian laboratories.
Design: Slides from TMA with 38 tissue cores were sent to 18 Canadian diagnostic IHC laboratories. All results were de-identified for the source and posted for viewing including protocols, Garrattograms, and virtual microscopy at www.ciqc.ca. Sensitivity, specificity, Kendall's W Test for concordance, and kappa statistics were calculated. MultiViewer enables side-by-side comparison of up to four different results by virtual microscopy. This feature is specific to virtual microscopy, more specifically to the MutiViewer, as this is not possible using actual microscopy.
Results: High average observed agreement, sensitivity, and specificity in ER, PR, and HER2 testing was observed (all > 90%). Kappa values were within the target range (> 0.8, or near perfect agreement) for all participating laboratories except the following: 1 laboratory for ER, 6 laboratories for PR, and 1 laboratory for HER2. Kendall's coefficient of concordance between the 18 laboratories was 0.942 for ER, 0.930 for PR, and 0.958 for HER2. False positive and false negative results could be identified as either interpretive or technical errors.
Conclusions: The first Canadian IHC EQA testing for ER, PR, and HER2 showed very high concordance between laboratories. The anonymous participation and unrestricted full access provides a means for rapid insight into technical or interpretive deficiencies, allowing appropriate corrective action to be taken.
Category: Quality Assurance
Tuesday, March 10, 2009 8:15 AM
Platform Session: Section F 1, Tuesday Morning