Cellular Viability of Whole Blood Specimens Is a Sensitive Indicator of Transport Conditions

Transporting specimens can expose them to uncontrolled environmental factors. Whole blood viability is a commonly used preanalytic marker of quality for analysis of white blood cells.

To evaluate whole blood viability as a marker for transportation and specimen integrity for lymphocyte subset evaluation.

More than 9000 whole blood specimens, transported during a 4-year period, and their lymphocyte subset evaluation results were analyzed retrospectively. Viability was measured by using Cellaca MX imaging cytometer, and lymphocyte and lymphocyte subset counts were determined with flow cytometry. Specimen cell viability results were stratified based on different transportation factors to discern their potential effects. Lymphocyte subset evaluation results from specimens with lower viability were compared with those from optimal viability specimens.

Cell viability of transported specimens exhibited seasonal variation, decreasing during the warm summer months (median, 77.0% versus 83.4% in other seasons). The decline in viability negatively correlated with ambient temperature during transportation (r = -0.7876). Longer transportation time (>60 hours) also caused a decrease in viability (median, 64.0%). While we observed a decrease in absolute cell counts for CD45+ lymphocytes, CD3+ T cells, CD8+ T cells, and CD19+ B cells in specimens with low viability (50%-80%), the differences were well within the assay's total allowable error.

Control of preanalytic factors is critical for laboratory testing. Whole blood viability is a sensitive indicator of transport conditions and time, but it is not a specific predictor of quality for the main lymphocyte populations in cellular immunology testing.