Figure 3

Receiver operating characteristic curve (ROC) analysis of serum free light chain ratio analysis in patients with dialysis-dependent renal failure. When using an abnormal serum FLC ratio as an indication of underlying multiple myeloma, comparison with the proposed renal reference range for the FLC ratio increased the area under the curve from that of 0.96 using the published reference range (green line, CI: 0.93–0.99; P < 0.001) to 0.99 with the new range (blue line, CI: 0.98–1.00; P < 0.001). Use of this new reference range did not change the sensitivity.