71. Validation of automated cell counter instruments for downstream cytogenetic testing

Counting while blood cells (WBCs) from blood and bone marrow samples before culturing aids in standardizing workflows, yields, and quality of downstream testing in the cytogenetics laboratory. However, traditional cell counting methods are limited in speed and accuracy, prompting the search for a high-throughput, reliable replacement method. Here, we describe the results from validations of two automated fluorescent cell counting instruments (Cellaca MX and DeNovix CellDrop FL) for use in a high-throughput cytogenetics laboratory setting. These instruments utilize imaging cytometry principles and Acridine Orange/Propidium Iodide (AOPI) stains for assessing cellularity and viability assessment and do not require lysing of non-nucleated cells. Both instruments underwent validation incorporating a range of performance criteria including accuracy, precision, reagent stability, cellularity range, and cytogenetic culture (mitotic index) performance. The Cellaca MX was initially validated against a traditional Coulter counter, followed by the validation of the CellDrop FL compared to the Cellaca MX. Validation samples representing the clinical diagnostic encounter and with sufficient cellularity to set up concurrent cultures were counted using the clinical and test methods. A minimum of 10 samples were used for accuracy and internal volume/cellularity thresholds were evaluated. Concurrent cultures were evaluated for mitotic index following dropping and staining to assess quality. Ranges of cellularity used for inoculums were established to culture at 1M cells/mL. Both instruments have shown reliable operation across the full clinical range of sample cellularity. Our work shows automated fluorescent cell counting instruments employing AOPI stains can provide accurate and reproducible results in a high throughput setting.