Wayne, Pennsylvania, USA-February 2011-The Clinical and Laboratory Standards Institute (CLSI) recently published Quality Assurance for Design Control and Implementation of Immunohistochemistry Assays; Approved Guideline-Second Edition (I/LA28-A2). This document provides guidelines for the development of validated diagnostic, prognostic, and predictive immunohistochemical assays, and is a revision of the previous CLSI document MM04.
The focus of this guideline is the application of immunohistochemistry (IHC) and immunocytochemistry (ICC) for the study of human tumor specimens. This guideline presents information on the total product life cycle of the discovery, design, development, verification, and analytical and clinical validation of IHC and ICC reagents, kits, and systems, while emphasizing that accurate and reliable IHC and ICC results require attention to the total test.
"The new CLSI IHC Quality Assurance document is easily the most complete and most comprehensive analysis of IHC technology and methodology, ever produced. It not only covers theoretical principles but also deals with assay (IHC stain) development by manufacturers, biospecimen handling, test performance and interpretation or scoring," said Clive R Taylor MD, D.Phil. FRCPath. MRCP(Ir), USC Department of Pathology.
IHC is an analytical technique that applies an antibody reagent to detect and visualize an antigen in cytological and surgical pathology microscopy specimens in the context of histomorphology and cytomorphology. The clinical-pathological interpretation of the presence and patterns of the antibody-antigen reactions is performed in a manner similar to other molecular pathology assays.
IHC is used in diagnostic pathology for diagnosis, determination of prognosis, and predictive assays for response to therapy. Accurate and reproducible results require quality assurance of the total test system, including the design control of the reagents and the preexamination (preanalytical), examination (analytical), and postexamination (postanalytical) interpretation steps (processes) of the assay to ensure its clinical applicability. This guideline focuses on validation of IHC assays on formalin-fixed, paraffin-embedded pathology material. Additionally, this document contains recommendations on design and statistical analysis of experiments for estimating the precision of IHC assay results.
The audience for this guideline includes the assay developer, the reagent supplier, the laboratory histotechnologist who performs the assay, and the laboratory director or pathologist who implements and interprets the assay.
CLSI is a volunteer-driven, membership-supported, nonprofit organization dedicated to developing standards and guidelines for the health care and medical testing community through a consensus process that balances the perspectives of industry, government, and the health care professions. For additional information, visit the CLSI website at www.clsi.org or call 610.688.0100.