Validation of automated fluorescent-based technology for measuring total nucleated cell viability of hematopoietic progenitor cell products

Background: A reliable rapid method for measuring total nucleated cell (TNC) viability is essential for cell-based products manufacturing. The trypan blue (TB) exclusion method, commonly used to measure TNC viability of hematopoietic progenitor cell (HPC) products, is a subjective assay, typically uses a microscope, and includes a limited number of cells. The NucleoCounter NC-200 is an automated fluorescent-based cell counter that uses pre-calibrated cartridges with acridine orange and DAPI dyes to measure cell count and viability. This study describes the validation of the NC-200 for testing HPC's viability.

Methods: Samples from 189 fresh and 60 cryopreserved HPC products were included. Fresh products were tested for viability after collection by both TB and NC-200. 7-aminoactinomycin D (7AAD) CD45+ cell viability results were obtained from a flow cytometry test. Cryopreserved products thawed specimens were tested for viability by both TB and NC-200. The NC-200 viability results were compared with the other methods. Acceptability criteria were defined as ≤10% difference between the NC-200 method and the other methods for at least 95% of the samples.

Results: Fresh products' mean viability difference between NC-200 and TB or 7AAD CD45+ method was 4.9% (95%CI 4.6-5.4) and 2.8% (95%CI 2.2-3.4), respectively. Thawed products' mean viability difference between NC-200 and TB was 3.0% (95%CI 0.4-5.6).

Conclusion: The NC-200 automated fluorescent-based method can be used effectively to determine HPC's viability for both fresh and cryopreserved products. It can help eliminate human bias and provide consistent data and operational ease.