update publication The Targeted Urine Proteome Assay (TUPA) consist of 200 potential urine protein biomarkers. TUPA uses scheduled multiple reaction monitoring (MRM) to determine protein expression based on two ?light? and two ?heavy?, stable isotope labeled tryptic peptides/protein, monitoring >1,600 transitions and using up to 8 data points (2 transitions/peptide) to determine the actual level of expression of each protein.