Updated project metadata. Major advances have been made to develop an automated universal 384-well plate sample preparation platform with high reproducibility and adaptability for extraction of proteins from cells within a culture plate. An in-solution digest strategy is employed to generate peptides from the extracted proteins for LC-MS analysis in the 384-well plate. Method evaluation utilized HeLa cells cultured in the 384-well plate ranging from 500 – 10,000 cells. Digestion efficiency was excellent in comparison to the commercial digest peptides standard with minimal sample loss while improving sample preparation throughput by 20 – 40 fold. Analysis of six human cell types, which included two primary cell samples identified and quantified approximately 4,000 proteins for each sample in a single LC-MS/MS injection with as little as 100 – 10,000 cells depending on cell type demonstrating universality of the platform. Implementation of the comprehensive 384-well format protocol for processing cells to clean digested peptides enables large-scale biomarker validation and compound screening through proteomic analysis.