Researchers generated a draft atlas of the human plasma proteome at isoform resolution by separating plasma into 3,114 intact protein fractions and analysing them using data-independent acquisition mass spectrometry. The study reports 5,077 plasma proteins circulating in at least 179,049 distinct proteoforms, with 44,083 detected at high confidence. Canonical protein forms account for less than half of the total protein mass in plasma. The atlas also helps explain discrepancies between Olink and SomaScan measurements and highlights proteoform diversity as a resource for biomedical research and biomarker discovery. This work was posted on bioRxiv on 28 September 2026 and is a preprint, not a peer-reviewed journal article. Our scientific co-founder and CSO, Markus Ralser, has led the study at Charité Berlin.