Ready-to-use ELISA kits are available for the detection of YKL-40, an alias of the protein, chitinase 3 like 1. The official gene symbol is CHI3L1. The kits can detect several species variants of the protein, including: human and other mammalian. The protein, with a mass of 42.6 kDa and length of 383 residues, is reported to be cytoplasmic and secreted. It is a member of the Glycosyl hydrolase 18 family and may be known by other names, including: GP-39, CGP-39, chitinase 3-like 1 (cartilage glycoprotein-39), cartilage glycoprotein 39, 39 kDa synovial protein, and chitinase-3-like protein 1, and HC-gp39.