Measurement of the amount in blood of a molecular chain compound composed of two or more amino acids joined by peptide bonds that is produced in one part or organ of the body and initiates or regulates the activity of an organ or a group of cells in another part of the body.
blood plasminogen activator inhibitor 1 level +
blood steroid hormone level +
blood tissue inhibitor of metalloproteinase-1 level +
blood troponin level +
blood type I collagen C-terminal telopeptide level +
blood vascular endothelial growth factor A (VEGF-a) +