Researchers split human blood plasma into over 3,000 fractions and analyzed them with mass spectrometry. The resulting atlas mapped 5,077 proteins and confirmed more than 44,000 distinct versions of them, called proteoforms — a median of 11 per protein.
Blood tests measure proteins to detect disease, and most tests assume one standard version of each protein. This atlas shows those standard versions make up less than half of the protein mass in plasma. It also helps explain why two major platforms, Olink and SomaScan, disagree on proteins that come in many forms.
✦ Your blood's proteins are families of forms, not single molecules — and most forms remain uncharted.