Abstract
As the therapeutic landscape for chronic lymphocytic leukemia (CLL) continues to expand, biological predictors of response to therapy are becoming increasingly important. One such predictive biomarker is the mutational status of the variable region of the immunoglobulin heavy chain (IGHV) gene, which is a powerful predictor of duration of response and overall survival with chemoimmunotherapy (CIT). As this test may influence choice of therapy between CIT and novel agents, it is critical that providers understand how mutational status is determined and the limitations of testing. Here, we describe the details of IGHV mutational status testing, highlighting the appropriate way to interpret this information and best apply it to the care of patients with CLL.