Miniaturization and multiplexing are two areas that need improvement in immunoassays. However, it is unclear how associated changes in size, substrate, binding capacity, protein concentration, and other parameters affect sensitivity and quantitative range. In the study here we compared a new protein microarray substrate and system (Zeta-Grip, Miragene Inc., Anaheim, CA) with enzyme-linked immunosorbent assay (ELISA) for the application of immunoassays. We found that the protein microarray system performed better than ELISA in both sensitivity and quantitative range for use in immunoassay.