Pair wise correlation of repeated protein microarray analyses. Pair wise correlation of repeated analyses of serum samples. Log2 transformed unnormalised intensities, with a threshold set to 512 intensity-units (derived from Genepix .gpr files) were used for analyses. Correlation coefficients are given in the paired scatterplots and were above 0.92 upon repetitive analyses. The "filled triangles" represent reactive clones from each individual serum found within membrane-based macroarray testing. Data from repetitive analyses (replicate-1 on x-axes; replicate-2 on y-axes) microarray analyses using serum from brain (left) and lung (right) tumour patients (identifiers of different patient sera on top of each scatter plot) are plotted.