Prof. Merlini, the session chair, provides an updated, foundational overview of the great impact that the free light chain (FLC) assay has had on improvements in screening, risk assessment, and the evaluation of therapy response for monoclonal gammopathies. FLC in particular is credited with revolutionizing the care of diseases caused by the proteotoxic effect exerted by light chains, such as AL amyloidosis, light chain deposition disease, and monoclonal gammopathies of renal significance. Further, Prof. Merlini outlines how the FLC assay may support further clinical excellence in the treatment of asymptomatic myeloma patients through the quantification of their serum FLC levels. Such quantification may help physicians decide when best to commence treatment.