Neil Kay, MD, Mayo Clinic, Rochester, MN, discusses measurable residual disease (MRD) testing in chronic lymphocytic leukemia (CLL). MRD assessment has increasingly been implemented in CLL trials, but its role in routine clinical practice has not yet been defined. Prof. Kay mentions flow cytometry and next-generation sequencing for MRD evaluation. Currently, MRD data from clinical trials suggest that patients on Bruton’s tyrosine kinase inhibitors plus an anti-CD20 antibody or venetoclax with undetectable MRD forecast for excellent durable responses. This interview took place at the Lymphoma, Leukemia & Myeloma Congress 2021.