FLOW CYTOMETRY FOR WHITE BLOOD-CELL COUNT S IN WHOLE-BLOOD AND BLOOD COMPONENTS

The measurement of absolute cell concentrations by flow cytometry is e asily possible using the commercially available latex particles FACSCo unt ControlsTM. The measurements presented here were performed on a FA CScanTM flow cytometer. Leukocytes were stained with monoclonal antibo dies anti-CD45/anti-CD14, and erythrocytes were lysed without followin g centrifugation. The method was validated with hematology controls an d normal blood samples in comparison with the automatic cell counter T echnicon-H1TM. Both methods revealed a good correlation in normal leuk ocyte 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.