Previous proteomic studies in IBD patients have revealed specific protein expression profiles that correlate with either Crohn's disease (CD) or ulcerative colitis (UC). Four potential protein markers, PF4, MRP8, FIBA and Hpalpha2, have been found, which appear to be characteristic of IBD and therefore can be used to screen for IBD in undiagnosed populations. In addition, a frequent problem of IBD is the difficulty of diagnosis between CD and UC, which may present similar symptoms and clinical picture and make it difficult for the attending physician to diagnose them and, consequently, to choose the appropriate treatment. Proteome analysis between these two groups has revealed specific expression profiles that correlate with either CD or UC and therefore, can be used as specific biomarkers. Corresponding proteomic analyzes with the aim of a better and more accurate diagnosis are also carried out in other diseases, such as neurological diseases (Parkinson's), leukemias, spondyloarthritis, psoriasis, etc.