111 - First comparative evaluation of leucocyte differential and reticulocyte count between Abbott Cell -DYN 3700 and Beckman-Coulter Gen S

H. Vandeputte, D. Darre, F. Leroy, J. Nemmiche, C. Pucalowski, MC. Chretien. Abstract. Background: The Cell-Dyn 3700 has been launched with the same CBC and flagging performance specifications as the Cell-Dyn 3500. The primary goal of our evaluation was to evaluate the new algorithms of its reticulocyte method and the performance capabilities in comparison to our routine analyser (Coulter Gen S). Methods: The WBC differential and reticulocyte counts were evaluated on the new Cell-Dyn 3700 instrument (Abbott Laboratories) on 758 normal and 727 pathological samples. Results: When compared to the routine laboratory analyser (Gen S, Beckman Coulter) in the normal population, similar WBC differential results were found. In contrast, we noted some differences within the pathological samples. A bias of 0,643 Giga/L WBCs (white blood cells) was found between Cell-Dyn 3700 and Gen S measurements in samples with WBC counts of less than 3 Giga/L (no. 89). For WBC counts less than 1 Giga/L the Cell-Dyn 3700 residual plots of linear regression analysis provided the closer fit to its regression line. FWBC (Fragile White Blood Cells) flag on the Cell-Dyn 3700 is a good indicator of the osmotic fragility of lymphocytes from CLL (chronic lymphocyte leukaemia). This highlights the limited linearity of impedance methods in these situations at a level of 100 Giga/L and above. The Cell- Dyn 3700 KWOC (Corrected White Optical Count) reported value is higher than the impedance and microscopy counts. This study also evaluated the new Cell-Dyn 3700 reticulocyte algorithm method. In the evaluation of 400 random samples, the Cell - Dyn 3700 analyser showed a significant bias compared to Gen S (0,4 %) in a population ranging from 0,37 to 8 % for Gen S and 0,17 to 9,44 % for Cell-Dyn 3700 (with the exception of one value at 14,7 %). Conclusions: These results suggest a clear improvement of the reticulocyte methodology on the Cell- Dyn 3700.