Urinary nucleic acids can be concentrated, dried on membranes and stored at room temperature in vacuum bags

11 Urine accumulates traces of changes that occur in the body and can potentially serve as a 12 better biomarker source. Urinary nucleic acids are a promising class of non-invasive disease 13 biomarkers. However, long-term frozen human urine samples are not a good source for the 14 extraction of nucleic acids. In this paper, we demonstrate that urinary nucleic acids can be 15 concentrated, dried on membranes and stored in vacuum bags at room temperature for several 16 months. The amount of total RNA on the membranes after storage at room temperature for three 17 months was unchanged. The levels of miR-16 and miR-21 exhibited no significant differences 18 (P = 0.564, 0.386). This simple and economical method makes the large-scale storage of clinical 19 samples of urinary nucleic acids possible. 20