A method and system for characterization of antibody-bound targets by sequencing of synthetic oligonucleotides bound to the antibodies, the method including: receiving a sample having a set of antibodies； conjugating each of the set of antibodies with an oligonucleotide, thereby generating a set of oligonucleotide-conjugated antibodies； binding a first subset of the set of oligonucleotide-conjugated antibodies to a set of targets at a capture substrate； determining a sequence for at least one of: 1) each oligonucleotide of the first subset of oligonucleotide-conjugated antibodies that bind to the set of targets and 2) each oligonucleotide of a second subset of the set of oligonucleotide-conjugated antibodies that fail to bind to the set of targets； and generating an analysis of the sample from the sequences determined from at least one of the first and the second subsets of oligonucleotide-conjugated antibodies.
