Much effort has been expended in optimizing antibody attachment to the microarray substrate. Finally, various signal generation and signal enhancement strategies have been employed in antibody arrays, including colorimetry, radioactivity, fluorescence, chemiluminescence, quantum dots and other nanoparticles, enzyme-linked assays, resonance light scattering, tyramide signal amplification, and rolling circle amplification. Each of these formats and procedures has distinct advantages and disadvantages, relating broadly to sensitivity, specificity, dynamic range, multiplexing capability, precision, throughput, and ease of use. In general, multiplexed microarray immunoassays are ambient analyte assays [160] . Given the heterogeneity of antibody array formats and procedures currently in use in proteomics studies, and the absence of a "gold standard," there exists an urgent need for development and adoption of standards that permit platform comparisons and benchmarking.