This experiment includes the data analysis shown in the section of Querying sequence variances with PECAN. Based on the UniProt Swiss-Prot human natural variant database, 342 proteins from the DIA plasma library are reported with a total of 4,264 single amino acid variants. We used PECAN to query variant-specific, tryptic peptides from the 4,264 variants against the plasma library data. Of the 4,264 variants, 3,714 variants resulted in at least one variant-specific peptide in the mass range of 600 to 4000 Da that are unique to the variant and not present in the human UniProt Swiss-Prot database. PECAN detected 133 variant specific peptides, corresponding to 115 variants. In some cases, PECAN detected multiple variant-specific peptides resulting from the same variants.