Anti-APOH antibodies are used in the immunodetection of the protein apolipoprotein H. In humans, the canonical protein has a reported length of 345 amino acid residues and a mass of 38.3 kDa. It is known to be a secreted protein. It is notably expressed by the liver and secreted in plasma. APOH is known to bind to various kinds of negatively charged substances such as heparin, phospholipids, and dextran sulfate. Post-translational modifications have been described, including O-glycosylation. Synonyms for this target antigen include B2GP1, BG, beta-2-glycoprotein 1, APC inhibitor, B2GPI, and B2G1.