Membrane-based cytokine arrays as semi-quantitative assay. (a) TNF-α signal derived from the membrane-based assay for six progressive dilutions of a pool of plasma obtained from two LPS treated rats. The concentrations range from 930 to 18 pg/mL (from left to right). In b, the correlation between the membrane-based assay intensity and ELISA concentration detected for the same samples measured with the two different techniques is shown. The red dashed lines delimited the 95% confidence interval.