Improved Sensitivity in the Measurement of Residual Leukocytes in Platelet Products Using an Automated Leukocyte Counter

Abstract

Background and Objectives: Leukocytes remaining in platelet concentrates may be responsible for side effects caused by platelet transfusion. A simple method of high sensitivity for determining trace numbers of leukocytes is currently needed. Materials and Methods: An automated leukocyte counter, the LD-1000, the principle of which is a combination of spinning down on the observation field of stained nuclei derived from a 100 μl neat sample and image digitization with a charge coupled device camera, was newly developed and tested for sensitivity and reproducibility. Results: While the theoretical lower limit of detection was 0.01 cells/μl, the limit of detection of the LD-1000 was verified to be 0.2 cells/μl. A good correlation (r = 0.86) was observed between the results obtained using the Nageotte method and the LD-1000. Repeated measurements also confirmed satisfactory reproducibility. Conclusions: The instrument provides a new method of enumerating residual leukocytes in platelet products with better sensitivity and easier procedure compared to the Nageotte method and will be useful for quality assurance purposes at blood centers.

The Development of Leukocyte Counter Using Fluorescence Imaging Analysis

“…In 2000, we developed a new method named the image cytometry centrifugation (ICC) method and the instrument to count leukocytes in the blood products (Yabusaki et al 1999Nagahashi et al 2000). It is a comparatively quick, easy, and cost-effective procedure.…”