Improved sensitivity in the measurement of residual leukocytes in plateletproducts using an automated leukocyte counter

Background and Objectives: Leukocytes remaining in platelet concentrates ma y be responsible for side effects caused by platelet transfusion. A simple method of high sensitivity for determining trace numbers of leukocytes is c urrently needed. Materials and Methods: An automated leukocyte counter, the LD-1000, the pri nciple of which is a combination of spinning down on the observation field of stained nuclei derived from a 100 mu l neat sample and image digitizatio n with a charge coupled device camera, was newly developed and tested for s ensitivity and reproducibility, Results: While the theoretical lower limit of detection was 0.01 cells/mu l , the limit of detection of the LD-1000 was verified to be 0.2 cells/mu l. A good correlation (r = 0.86) was observed between the results obtained usi ng the Nageotte method and the LD-1000, Repeated measurements also confirme d satisfactory reproducibility. Conclusions: The instrument provides a new method of enumerating residual l eukocytes in platelet products with better sensitivity and easier procedure compared to the Nageotte method and will be useful for quality assurance p urposes at blood centers. Copyright (C) 2000 S. Karger AG, Basel.