Accurate measurement of viable cell density (VCD) and viability is essential for consistent performance in cell culture processes. Automated cell counters are widely used, but ensuring their comparability is critical for data integrity and reliable decision making.

Instrument and operator variability can introduce measurement error, affecting process control and product quality. Without a statistically validated measurement system, confidence in data precision and accuracy is compromised.

A structured experiment was designed using crossed Gauge R&R, a core method in measurement system analysis (MSA), to isolate sources of variation (equipment and operator). Identical samples were measured across equipment-operator combinations. JMP was used to calculate % Gauge R&R, variance components, and precision-to-tolerance (P/T) ratios, providing a robust assessment of comparability across the equipment. Interactive JMP visualizations (such as variability charts and component plots) provided clear insight into the dominant sources of variation and system comparability.

The analysis showed that biological (part-to-part) variation dominated, while measurement system variation was minimal. VCD measurements were statistically consistent across instruments. Viability showed slightly higher variability but remained within acceptable thresholds. Both instruments were deemed statistically comparable and interchangeable.