Quality control procedures for flow cytometric applications in the hematology laboratory

Clinical diagnosis is one of the areas in which flow cytometry (FCM) has gained wide popularity and FCM now plays a crucial role in several aspects of medical hematology. It has progressively replaced many traditional laboratory tests due to its greater accuracy, sensitivity and rapidity. Unfortunately, among the very large number of its potential applications, only a minority of flow cytometric protocols have been standardized. Numerous factors are responsible for variation in analytical conditions and may affect results obtained by FCM. All these variables can be schematically divided into three major groups: factors related to the biological samples, immunological and accessory reagent factors and factors associated with the use of instruments. The quality control program must monitor and evaluate all aspects of the procedure. This includes the following main aspects: 1) performance of the flow cytometer, 2) specimen collection, transportation and maintenance of its integrity, 3) reagents, particularly monoclonal antibodies and 4) sample measurement, data acquisition and their interpretation. Procedures described here are designed to assess all the settings which affect the reliability, reproducibility and sensitivity of the cytometer in order to ensure identical conditions on a daily basis.