Practical application of cell counting method performance evaluation and comparison derived from the ISO Cell Counting Standards Part 1 and 2

Abstract

The increased utilization of cells in biomanufacturing and as therapeutic products over the last decade has prompted the development and publication of two ISO Cell Counting Standards, ISO 20391 – 1:2018 and ISO 20391 – 2:2019 to provide guidance on general principles relating to cell counting and to establish an approach to evaluate the quality of cell counting methods. In this work, we demonstrate the practical implementation of the experimental protocol outlined in ISO Cell Counting Standard Part 2 and a Bland-Altman comparative analysis to evaluate performance and comparison of cell counting methods. We compare two cell types, two image cytometry instruments, and two fluorescent stains, calculating the precision, coefficient of determination (R2), and a proportionality index (PI) parameter to evaluate cell counting method performance. In addition, the cell counting results are directly compared to evaluate bias between two cell counting methods. The protocol is suitable for evaluating and comparing the performance of multiple cell counting methods to select for downstream assays.