[Evaluation of Cell-Dyn 3500 in extreme values]

The quality tests made during the preparation of labile blood products permit to validate the product and to make sure the making procedures are applied properly. The labile blood products have to correspond to a number of standards set by a ministerial order. It is thus necessary to check the manufacturing unit of some products. On account of the original technology of Cell-Dyn 3500 which associates methods of impedance variation measure analysis and flow cytometric technique analysis on non-marked cells, and of its veterinary modulus permitting counting in extreme values, it seemed to be worth being evaluated in a blood bank quality control laboratory. Linearity was studied from a range of dilutions obtained from high value samples prepared by the centrifugation of blood bags and collection of the buffy coat by Optipress system. The study was performed on 22 samples. The linearity in the counting of red cells, white cells, platelets and haematocrit was measured. Intersample contamination was measured. It focused on the values of platelets and white cells. A sample of high cell concentration prepared in the condition mentioned above and a white cell-reduced blood concentrate were used. The study of repeatability was done by treating 20 times three samples covering a wide range of values of the different parameters of cell numeration. The linearity concerning parameters and the range of the values studied are good (example: from 10 to 3000 10(9)/l for platelets). Contamination is low for white cells and non appreciable for platelets. Repeatability shows excellent variation coefficients.