Sample Treatment for Urine Proteomics.

Urine is a biological fluid that can be collected noninvasively in relatively large quantities which can be used for the search of biomarkers of disease, both diseases of the urological tract and systemic diseases. One of the most important aspects in proteomic studies is sample treatment before further analysis. Methods of preparation of a urine sample depend on the techniques that will be used later for separation and identification of the proteins. Also, urine preparation should be as simple as possible to increase reproducibility. Normal urine has a much diluted protein concentration with a high-salt content, which interferes with proteomic analysis. Thus, an initial step in the handling of urine sample should be to concentrate and eliminate salts. As range of protein concentrations in urine spans several orders of magnitude, effective proteomic analyses require either removal of most abundant protein or enrichment of the less abundant ones. In this chapter, we discuss the aspects related to the collection and treatment of urine for proteomic studies.