Anti-chitinase acidic antibodies are used for the immunodetection of the protein encoded by the CHIA gene. In humans, the canonical protein has a reported length of 476 amino acid residues and a mass of 52.3 kDa. It is known to be a secreted protein. Alternative splicing is reported to yield 3 different isoforms for this protein. It is notably expressed in the lung epithelial cells from asthma patients. A member of the Glycosyl hydrolase 18 protein family, it is known to be involved with the apoptotic pathway. Other names for this target antigen include CHIT2, TSA1902, acidic mammalian chitinase, lung-specific protein TSA1902, and AMCASE. Gene orthologs have been identified in the frog and bovine species.