Anti-CHI3L1 antibodies are used in the immunodetection of the protein chitinase 3 like 1. In humans, the canonical protein has a reported length of 383 amino acid residues and a mass of 42.6 kDa. Its subcellular localization is in the ER, cytoplasm, and is also secreted. A member of the Glycosyl hydrolase 18 protein family, it is known to be involved with the apoptotic pathway and carbohydrate metabolism and homeostasis. Post-translational modifications have been described, including glycosylation. Synonyms for this target antigen include CGP-39, GP-39, GP39, HC-gp39, HCGP-3P, YK-40, YKL-40, and ASRT7.