Anti-angiopoietin like 4 antibodies are used in the immunodetection of the protein encoded by the ANGPTL4 gene. In humans, the canonical protein has a reported length of 406 amino acid residues and a mass of 45.2 kDa. Its subcellular localization is in the extracellular matrix and is also secreted. Alternative splicing is reported to yield 3 different isoforms for this protein. It is notably expressed in blood plasma. It is known to mediate inactivation of the lipoprotein lipase LPL, and thereby plays a role in the regulation of triglyceride clearance from the blood serum and in lipid metabolism. Post-translational modifications have been described, including N-glycosylation and protein cleavage. Other names for this target antigen include FIAF, HARP, HFARP, NL2, PGAR, TGQTL, UNQ171, and ARP4.