Type of protein/peptide quantification, where the relative amounts of one protein in different samples is determined, i.e. the ratio of the content of a protein/peptide in sample 1 to sample 2.
Source:
PAC, 2018, 90, 1121. 'Terminology of bioanalytical methods (IUPAC Recommendations 2018)' on page 1164 (https://doi.org/10.1515/pac-2016-1120)