Urine is a readily available biospecimen with utility for research and clinical testing. Its non-invasive nature proves to be advantageous over other biospecimens. Among the proteins detected in urine, approximately 70% originate from the urinary tract. The remaining 30% come from filtered blood, meaning that urine samples could serve as an alternative to serum or plasma for biomarker discovery and monitoring. Traditionally, urine has been difficult for analysis by mass spectrometry because of low peptide abundance, high concentrations of salts and metabolites like urea, and degradation of proteins in the sample. Previous studies focusing on urine have utilized LC-MS due to its high sensitivity and ability to detect low-abundance proteins and have identified >5,800 unique proteins in urine. This pilot study utilized 80 urine samples: 69 positive for drug use (via Discovery Life Science’s biospecimen inventory) and 11 obtained from healthy volunteers at baseline, post-exercise, and post-fasting conditions. This work demonstrates the potential of urine as a biofluid for deep biomarker discovery, with the combination of Seer Proteograph XT and Orbitrap Astral delivering comprehensive proteomics data sets from which we can gain significant insight.
