Determination of residual disease by flow cytometry in chronic lymphocytic leukemia: state of play of technical practices and prospects

Minimum Residual Disease (MRD) assessment in chronic lymphocytic leukemia (CLL) is restricted to clinical trials according to good practice recommendations. Flow cytometry (FCM) is the preferred method for this specialized activity but little is known as regard to its use in routine laboratory practice. Early 2019, a survey was conducted in laboratories with flow cytometry departments, concerning the practice of MRD tests in CLL. Eighty responses were collected, allowing us to define the landscape of CLL MRD assessment in France. This study shows that MRD tests are mainly performed by hematology laboratories in public hospitals, but in a reduced number of centers. However, numerous laboratories wanted to receive training and join a working group on the subject. This work highlights the need for an evolution of the practices to make MRD test more broadly available, anticipating a possible evolution of the indications of this test in the follow-up of treated CLL patients.