Urine is a valuable biological sample that contains huge amounts of information with high diagnostic and prognostic value. The non-invasive and easy method underlying urine collection allows the repetitive assemblage of urine in large quantities and in different time points. Urine samples have become a standard sample on medical diagnosis and widely applied in proteomics cohort studies for biomarker discovery. In proteomics studies, the variety present in urine samples from different specimens represents one of the major drawbacks in urine sample handling and storage. Furthermore, the development of a new standard and optimized methodology for urine sample handling is required. Currently, the common urine storage method is by freezing at - 20 or - 80 ˚C. This method requires specific dedicated refrigerators, and the effect of freeze-thaw cycles have been showed to induce proteome alterations which is not ideal for urine biomarker discovery. In this work, we aim to overcome this limitation by developing a new method for urine preservation and storage at room temperature. Samples were storage for 6 months and compared using mass spectrometry label-free quantification. We were able to prove that both storage methods could effetely storage the urine proteome for at least 6 months without significant alterations in the preserved proteome. We have validated a new storage and preservation method for urine preservation at room temperature
