FLOW CYTOMETRY FOR WHITE BLOOD-CELL COUNTS IN WHOLE-BLOOD AND BLOOD COMPONENTS

The measurement of absolute cell concentrations by flow cytometry is easily possible using the commercially available latex particles FACSCount ControlsTM. The measurements presented here were performed on a FACScanTM flow cytometer. Leukocytes were stained with monoclonal antibodies anti-CD45/anti-CD14, and erythrocytes were lysed without following centrifugation. The method was validated with hematology controls and normal blood samples in comparison with the automatic cell counter Technicon-H1TM. Both methods revealed a good correlation in normal leukocyte counts. Dilution experiments were performed to define the lowest range of detectable cell counts. Calculated and measured cell counts coincided down to 0.5 leukocyte/mu l. Leukocyte counts measured in the Nageotte chamber and flow cytometry correlated well. The coefficient of variation increased from 3% in hematology controls to a maximum of about 20% in a leukocyte range lower than 1/mu l.