Minimal residual disease (MRD) refers to the small number of leukaemia cells still left in the body after remission. MRD measures the presence of leukaemia in the body at a molecular level rather than at a cellular level.
As with immunophenotyping, MRD involves tagging the leukaemia cells with fluorescent markers and measuring them using flow cytometry.
Following complete remission, evidence of MRD could warn of patients’ chances of relapsing.
MRD testing can monitor the presence of leukaemia cells both during and after treatment. It provides a sensitive assessment of remission, and an early detection of relapse.