Effect of increasingly abnormal FLC ratio on the relative risk of progression of SMM to MM or related disorder. As the serum kappa/lambda FLC ratio becomes increasingly abnormal, the risk of progression increases. The middle curve in represents relative risk; upper and lower curves represent 95% confidence intervals. Vertical bars represent the normal range for kappa to lambda ratio. (A) Unadjusted. (B) Adjusted for BMPC count and M protein.