Peptide array quality control

A method for determining quality and fidelity of an in situ synthesized immunosignature array, wherein the in situ synthesized immunosignature array comprises an array of peptides, the method comprising:

• obtaining a specific binding strength of each peptide of the in situ synthesized immunosignature array, wherein the specific binding strength is obtained from binding with a first sample, the first sample comprising a biological sample from a subject;
• obtaining a background binding pattern of an immunosignature reference array, wherein the background binding pattern is represented by a mean binding strength of empty control regions in the immunosignature reference array;
• and
• measuring a standard deviation of the specific binding strength of each peptide compared to the background binding pattern, wherein a measurement of more than three standard deviations establishes synthesis quality and fidelity of the in situ synthesized immunosignature array.