Controls for flow cytometers in hematology and cellular immunology.

The necessity of using freshly prepared biological samples to control and calibrate flow cytometers has impeded the utilization of flow cytometry in the clinical laboratory where regulations demand careful control calibration and yet workload and technician training militate against the preparation of specialized control samples. For a number of years, cell preparations with stabilized properties have been used routinely in hematology laboratories to evaluate the daily performance of automated blood cell counters including optical flow cytometers. Unfortunately, the stabilized preparations do not necessarily duplicate many important aspects of whole blood, resulting in variable performance of a given control preparation on different types of instrumentation. The new generation of hematology analyzers measures a host of new parameters and will require more sophisticated controls for these enhanced parameters. Some practical aspects of present and future hematology controls will be discussed. Immunology, a new area for automated cell analysis, can benefit greatly from controls both for instrument performance and for cell staining. Up to this time there has been little availability of control materials suitable for clinical immunology. We have been evaluating fluorochrome-stained cell nuclei for use as an instrument control and for calibration of immunofluorescence analyses. Our development and use of this type of control will be described. We will also discuss approaches and experiments aimed at producing cells with stabilized antigenic properties which can be stained with monoclonal antibodies and can thus act as actual reagent controls.