Flow cytometry is used as a simple, rapid method for detection of minimal residual disease (MRD), the persistence of malignant cells in the bone marrow or other tissues of patients with hematologic malignancies after remission at levels below the limit of detection by conventional morphologic assessment. It is believed that these residual malignant cells are the source of disease relapse in many patients, although additional therapy to eradicate very small numbers of residual cells does not improve survival in all patients. Researchers are actively evaluating the significance of MDR.
Flow cytometric analysis is less sensitive than the polymerase chain technique for MRD, but it is simple and rapid to perform, provides quantitative data, and has adequate sensitivity in many leukemia cases. Flow cytometric analysis detects the presence of aberrant immunophenotypic features that are not characteristic of normal cell populations in the specimen under study.(15.)
