The CLSI has published the Quality Assurance for Design Control and Implementation of Immunohistochemistry Assays; Approved Guideline - Second Edition (I/LA28-A2) document.
The 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 tumour specimens.
The guideline presents information on the total product lifecycle of the discovery, design, development, verification, and analytical and clinical validation of IHC and ICC reagents, kits, and systems, while emphasising that accurate and reliable IHC and ICC results require attention to the total test.
IHC is an analytical technique that applies an antibody reagent to detect and visualise 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 pre-examination (pre-analytical), examination (analytical), and post-examination (post-analytical) 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, the 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.
