Figure 4.

Kaplan–Meier analysis of PFS based upon (a) the ISS that utilizes elevated serum β₂-M and low albumin concentrations. Stage I (green, n=140) β₂-M <3.5 mg/l and albumin ⩾35 g/l, stage II (blue, n=102) not stage I or II, stage III (red, n=60) β₂-M >5.5 mg/l; (b) a risk stratification based upon elevated serum β₂-M and more extreme HLC κ/λ ratios (within or outside of 0.01–200) as a replacement for albumin. Low risk (green, n=124) β₂-M <3.5 mg/l and a less extreme HLC ratio (0.01–200), intermediate risk (blue, n=122) either β₂-M >3.5 mg/l or an extreme HLC ratio (<0.01 or >200), high risk (red, n=62) both β₂-M >3.5 mg/l and an extreme HLC ratio (<0.01 or >200).