Quality Assurance for Clinical Flow cytometry

Abstract

Flow cytometry is an indispensable methodology for immunological tests like immuno phenotyping of leukemic cells. Recently, it is becoming increasingly important to measure absolute count of particular cell populations, for example, enumerating CD34+ cells in hematopoietic stem cell transplantation and counting CD4+ T cells in HIV infection. Thus, quality control processes only focused on verifying optical alignment and instrument settings are not sufficient for quality assurance for clinical flow cytometry. Operators also need to pay close attention to both the precision and the accuracy of their measurements. Therefore, not only internal quality control but also external quality control is necessary for meaningful quality assurance for clinical flow cytometry. While the implementation of internal QC processes is possible by the use of appropriate control materials, there are no official external QC programs for clinical flow cytometry available in Japan. The Interlaboratory Quality Assurance Program (IQAP) is an external QC program provided by Beckman Coulter. In this program, the accuracy and the precision of measurements from each participant are simultaneously evaluated and compared to the pooled data from all participants. In this paper, I briefly illustrated the basic outlines of quality assurance for clinical flow cytometry as well as important points to consider when interpreting statistical data. I then summarized some IQAP results and showed the effectiveness of process automation for better precision, the importance of accurate lymphocyte gating for better accuracy, and the usefulness of CD45 for more appropriately gating lymphocytes.