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Jan Klos

Hematolymphoid markers

– results of the 1st decennium in NordiQC


During the last decennium (2003-2012) the NordiQC organization has conducted 36 runs with 5-6 epitopes each, assessing totally 85 different epitopes where majority was evaluated numerous times. Among them were 27 different epitopes of relevance in diagnostic hematopathology, comprising 32% of all markers evaluated. On average ~100 laboratories were participating in assessment of each epitope. The highest number of laboratories (187) participated in the assessment of CD5 while only 7 submitted CD14 stains. As many as 140 different concentrated antibodies and 113 different RTU products from 19 different vendors were submitted by the participants during all runs. Ten epitopes (ALK, BSAP, CD8, CD14, CD19, CD45, CD163, IgLambda, MUM1 and TdT) were evaluated only once. The other 17 epitopes (Bcl-2, Bcl-6, CD3, CD4, CD5, CD10, CD15, CD20, CD23, CD30, CD34, CD68, CD79a, CD138, Cyclin D1, IgKappa and IgM) were evaluated on several (2-4) assessments due to poor pass rate or increased number of new participating laboratories.
The results confirm that External Quality Assurance is crucial for identification of poorly calibrated IHC systems which are not detected by internal quality control at the laboratories. The percentage of successful results (assessed as optimal or good) varied greatly among the runs and epitopes, ranging from 34% for IgLambda to 100% for CD14 according to last registered run. On average were 25% of participants assessed with insufficient results (borderline or poor) as compared to average 31% for all markers. The common reasons of insufficient staining were: inappropriate concentration of primary antibody (39%), inappropriate (most often inefficient) antigen retrieval (31%) and use of less successful antibodies (18%). The less common errors (12%) included inappropriate calibration of the protocol, use of biotin based detection system and drying-out of sections after HIER or technical errors. Interestingly, we found that performance of some antibodies/products was dependent on staining platform. Only 80 (57%) out of 140 concentrated antibodies fulfilled criteria for successful antibody (defined as at least one laboratory achieving optimal score with given product). Among 113 RTU products only 55 (49%) achieved an optimal score. For some antibodies/products the low number of participants submitting particular clone/product could have an influence on these results. The use of appropriate control tissue and focus on Critical Stain Quality Indicators are crucial for proper calibration of protocols and optimal staining results.


Dr. Jan Klos MD is a Senior Consultant and a  Head of the Immunohistochemistry Section in the Department of Pathology, Stavanger University Hospital, Norway.  He was educated at Medical University of Warsaw (1968-1974), trained and practiced pathology in Warsaw, Poland (1975-1982). Since 1982 he has been practicing and teaching pathology abroad, working first at the University of Jos, Nigeria (1982-84), later at the Central Hospitals in Falun and Gavle as well as University of Umeå, Sweden (1984-1998) and since 1998 in Stavanger, Norway.  His professional interest is diagnostic pathology main focus on hematopathology, pathology of the breast and cytopathology.  He is a co-author of more than 30 publications in the field of pathology.  He is a member of Editorial Board of Polish Journal of Pathology. Since 2009 he is a member of the core group in NordiQC representing there also Norwegian Society of Pathology.  He has been actively involved in teaching immunohistochemistry since 2000 as an invited lecturer on various international and national courses and meetings and since 2008 also as a co-organizer of annual NordiQC Workshops in Immunohistochemistry.

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