Fig. 4

Sensitivity and range of detection of the protein assays. a Scatter plot of RFU values for the 49 shared proteins comparing correlated and non-correlated proteins in the Discovery and SOMAscan assays. The RFU values between the correlated and non-correlated proteins in each assay were compared using a Mann-Whitney test (b). Median RFU of VEGF, IL-13 and TARC from the SOMAscan and Discovery assays were tested for correlation using Spearman’s rank correlation coefficient; only TARC showed significant positive correlation (r = 0.867, p < 0.001). Correlation graphs of the non-correlated, high abundance VEGF and low abundance IL-13 showed limited range of RFU in the SOMAscan assay compared to the Discovery assay, in contrast to the correlated TARC protein