Predictive value of a novel parameter sFLC(κ + λ) and relationship with sFLC(κ/λ) ratio. (A) Kaplan-Meier curves demonstrating a significantly shorter 3-year TFS for those CLL cases with sFLC(κ + λ) reaching or exceeding the cut-off value (51.8%, χ² of log-rank 85.6, P < .0001). (B) Comparison of CLL cases in terms of sFLC(κ/λ) and sFLC(κ + λ) variables with respect to sFLC(κ + λ) cut-off value of 60.6 mg/mL. Of a total of 449 cases, 277 (61.7%) had normal sFLC(κ/λ) and sFLC(κ + λ) below the cut-off, 62 (13.8%) had both abnormal sFLC(κ/λ) and sFLC(κ + λ) above the cut-off with a concordance rate of 75.5%, 110 cases were discordant (24.5%) with 22 normal sFLC(κ/λ) and sFLC(κ + λ) above the cut-off, and 88 with abnormal sFLC(κ/λ) and sFLC(κ + λ) below the cut-off. (C) Estimated Kaplan-Meier curves of TFS according to the combination of sFLC(κ/λ) abnormality and sFLC(κ + λ) cut-off value. To better illustrate the predictive impact of summated sFLC on TFS, separate curves for patients with normal (D) or abnormal sFLC ratio (E) are shown with respect to the sFLC(κ + λ) cut-off.