ProtoArray Human Protein Microarray version 4.0 enables screening biological samples or labeled probes of interest against 8,000 unique human proteins in a single, rapid experiment. Full-length, native human proteins from a broad range of protein classes are arrayed in duplicate on nitrocellulose coated glass slides. These high content protein microarrays are utilized for identification of disease-specific protein biomarkers, mapping protein-protein interactions, antibody specificity profiling, and target discovery and validation.