Effect of increasingly abnormal FLC ratio on the relative risk of progression of monoclonal gammopathy of undetermined significance to multiple myeloma or related disorder. This figure illustrates that as the serum kappa-lambda FLC ratio becomes increasingly abnormal, the risk of progression increases (A) and that this effect is present even after adjusting for differences in the serum monoclonal protein spike among patients (B). The middle curve in both figures represents relative risk; upper and lower curves represent 95% confidence intervals.