Figure 1. Example workflow for deciphering the urinary proteome/peptidome.

Each step of the workflow should be optimized based on pathophysiology, and pre-analytical, analytical, post-analytical variables. Freezing urine specimens prior to centrifugation ensures that the cellular elements will be lysed and the cytoplasmic contents will contribute to the overall proteomic signature. Due to the large dynamic range of urinary protein concentrations, a variety of technologies are utilized to enhance the ability to detect low abundance urine proteins/peptides. Not all analytical platforms perform each step; however, the processes that are utilized in the test set/training set/pilot study should be identical to the processes used in the validation and verification studies.