Figure 3.

Comparison of C1‐INH concentration by Optilite and RID. The C1‐INH concentration was measured using the Optilite assay, and compared to the radial immunodiffusion (RID) method used routinely in the clinical laboratory. Two hundred and sixty serum samples from patients with, or undergoing investigation for angioedema were used. Comparison between the two assays was assessed using A, Passing‐Bablok analysis (identity line shown where y = x) and B, Bland‐Altman analysis (solid line demonstrates the mean difference and broken lines show the limits of agreement, −1.96 and +1.96 standard deviations)