American Red Cross Philadelphia, Pennsylvania, United States
Background/Case Studies: Leukapheresis and autologous stem cell collections rely on hematology analyzers for their white blood cell (WBC) count results. The WBC drives the downstream processing of these valuable products, including concentration calculations. To date, hematology analyzers have been built with only whole blood samples in mind. Evaluation of these analyzers by individual laboratories is then necessary for different types of cellular therapy products. Our study documents the preliminary evaluation of the Abbott Cell-Dyn Ruby Hematology Analyzer (Ruby) against our hematology analyzer of more than twenty years, the Beckman Coulter AcT 5diff CP (Coulter).
Study
Design/Methods: The Coulter has been our main source of complete blood count (CBC) and differential results for upwards of two decades. The Coulter was used as our reference instrument when evaluating the Ruby for CBC testing. For a period of approximately three months (78 days total), we ran the Coulter and Ruby in parallel for both autologous stem cell products and leukopak products (via leukapheresis). Both pre and post processing samples were tested for the leukopak products. We chose to focus on the WBC count for this study, as this is the value that drives the processing of these units. 154 readings were obtained on both the Coulter and the Ruby: 39 – Autologous Stem Cell products, 62 – PRE-processed leukopak products, 53 – POST-processed leukopak products. A correlation coefficient (CC) and coefficient of determination (R2) greater than or equal to 0.9 was predicted.
Results/Findings: All controls for both the Coulter and the Ruby performed as expected. Using a linear regression model, the Coulter vs. Ruby comparison for the total sample size (n=154) resulted in a CC of 0.9965 and an R2 of 0.993 (Table 1). We then broke down the results into their three separate categories: Autologous Stem Cell products (STEM), PRE-processed leukopak products (L-PRE), and POST-processed leukopak products (L-POST). Linear regression of STEM (n=39) resulted in a CC of 0.9967 and an R2 of 0.9934 (Table 2), L-PRE (n=62) resulted in a CC of 0.9821 and an R2 of 0.9646 (Table 3), and L-POST (n=53) resulted in a CC of 0.9885 and an R2 of 0.9772 (Table 4). When comparing CC’s of each population, it was determined that the results were statistically significant. Conclusions: All CC and R2 values were above the predicted 0.9 and determined to be statistically significant. This preliminary study has potential for comparison of additional variables such as Red Blood Cell (RBC) count and corresponding Hematocrit (HCT). HCT is sometimes used as a quality metric for collections staff and so additional investigation into this value may be necessary in the future. Ultimately, a hematology analyzer optimized for cellular therapy products would be ideal. As the biotherapies field continues to grow, involvement from the vendors would make changing with the times even easier.
Importance of research: Leukapheresis processing and autologous stem cell collections rely on hematology analyzers for their WBC results; results which drive their downstream processing. These analyzers are built with only whole blood in mind. Evaluation of these analyzers is necessary for different types of cellular therapy products in each individual laboratory. Publication of this data will potentially bring opportunities to work with the vendors and increase their direct interest in cellular product testing.
