Explore the proteins in human blood

The Blood Proteins section presents estimated plasma concentrations of the proteins detected in human blood from mass spectrometry-based proteomics studies, published immune assay data and a longitudinal study based on proximity extension assay (PEA). Further, an analysis of the “human secretome” is presented including annotation of the genes predicted to be actively secreted to human blood, as well as to other compartments or organ systems of the human body such as the digestive tract or the brain. More information about the specific content and the generation and analysis of the data in this section can be found in the Methods Summary.

Learn about:

  • the plasma levels of blood proteins in a longitudinal study of healthy individuals
  • the levels of plasma proteins using immune assays and mass spectrometry-based proteomics
  • the classification of the human secretome (proteins secreted from human cells)


The Human Plasma Proteome chapter presents the estimated protein concentrations of proteins detected in human plasma based on immunoassays and mass spectrometry-based proteomics, respectively.

Plasma concentrations for 435 proteins predicted to be secreted in blood have been collected from immunoassay based studies in literature and are displayed together with information on their predicted function. Further, plasma concentrations and functions are presented for 4072 both secreted and leakage proteins estimated from mass spectrometry-based proteomics studies publicly available in the Peptide Atlas database. Finally, plasma levels for 1456 proteins measured in a two year longitudinal study of healthy individuals using proximity extension assay combined with next generation DNA sequencing (Olink Explore) will be presented.

Proteins detected
by immmunoasay

Proteins detected
by MS

Proteins detected
by PEA


The proteins secreted by human tissues (the secretome) are important for the basic understanding of human biology, but also for the identification of potential targets for future diagnostics and therapy. Based on a genome-wide analysis of the human protein-coding genes in which the secretome was identified as proteins with a signal peptide and no transmembrane-spanning region altogether 2793 genes were identified, corresponding to approximately 14% of the protein-coding genes. A systematic analysis of these genes has been performed with the aim to through literature, bioinformatics and experimental data annotate each gene with a single final location in the human body, including blood, digestive tract and intracellular compartments like Golgi and ER. Included in the human secretome are further 148 predicted secreted genes coding for different parts of the immunoglobulin proteins. Below the genes annotated to each of the compartments are displayed and the complete list, as well as, information on function and tissue specificity can be obtained by clicking the corresponding icon.

The human secretome

Secreted to extracellular matrix

Secreted to blood

Secreted in other tissues

Secreted in brain

Secreted - unknown location

Secreted to digestive system

Secreted in male reproductive system

Intracellular and membrane

Immunoglobulin genes

Secreted in female reproductive system