Measuring disease levels in myeloma using flow cytometry in combination with other laboratory techniques: Lessons from the past 20 years at the Leeds Haematological Malignancy Diagnostic Service.

People with myeloma who obtain a good response to treatment have a better survival if sensitive molecular or flow-cytometric techniques show no detectable minimal residual disease (MRD). The application of MRD techniques to clinical trials is now considered to be increasingly important because treatment approaches are sufficiently effective that using survival outcomes is slowing down the identification of the best new treatments. The articles in this issue consider the laboratory requirements for harmonization of MRD analysis by flow cytometry but there are practical considerations that are also important in implementing a myeloma MRD assay in the cytometry laboratory. In particular, it is important to consider when to request, and how best to utilize, a bone marrow aspirate sample because the procedure is invasive and the cells obtained are valuable for a number of different investigations. This brief article considers some experience obtained over two decades of implementing a service for MRD detection, initially as a scientific bolt-on to clinical trials through to a routine clinical diagnostic assay.