Analyte characterization via iterative analysis

A system for characterizing proteins from a sample, comprising:

• a substrate having proteins deposited thereon, each protein of the proteins attached to unique spatial addresses on the substrate;
• a fluidic system configured to expose the proteins attached to the unique spatial addresses on the substrate to a series of affinity reagents;
• a detector configured to determine an observed binding measurements model indicating positive binding measurement outcomes and negative binding measurement outcomes for the proteins binding to the series of affinity reagents;
• and
• a computing device comprising one or more computer processors, configured to:
• receive a first probe probability binding model indicating estimated probabilities of the series of affinity reagents binding to one or more candidate proteins that may be in the sample;
• assign, to each candidate protein, a pseudocount for each protein of the proteins, wherein the pseudocount is a value proportional to the calculated probability for the protein being identified as the candidate protein, the pseudocounts calculated based on (i) the observed binding measurements model and (ii) the first probe probability binding model;
• and
• quantify the proteins by summing, for each of the candidate proteins, the pseudocounts across all the proteins to determine a first abundance for each of the candidate proteins.