Issues for quality assurance in clinical flow cytometry.

An increasing number of clinical laboratories are using flow cytometry to analyze cells stained with fluorescent antibodies or dyes. Many articles discuss the analytical performance of immunofluorescent assays and DNA staining procedures. However, quality assurance transcends the performance of analytical methods and includes preanalytic, analytic, and postanalytic phases of the test procedure. This review focuses on preanalytic and analytic factors that affect the results of flow cytometric analysis of cells stained with fluorescent antibody or dyes specific for nucleic acid. The article reviews the controls used to assess instrument performance followed by a discussion of biological variables, and reagent, methodological, and instrumental factors that may affect the interpretation of these results.