Richard Rosenquist, MD, PhD, Karolinska Institute, Stockholm, Sweden, discusses the importance of re-testing in chronic lymphocytic leukemia. Dr Rosenquist briefly discusses three types of genomic tests conducted in CLL, including fluorescence in situ hybridization (FISH) analysis, TP53 screening, and testing of immunoglobin heavy chain gene (IgHV) mutational status. Dr Rosenquist then explains that in cases of relapse or disease progression, both FISH and TP53 analysis must be performed again to improve subsequent lines of treatment. This interview took place during the 2nd ESH Translational Research Conference on Chronic Lymphocytic Leukemia (ESH CLL), 2022.