Ready-to-use ELISA kits are available for the detection of antithrombin, an alias of the protein, serpin family C member 1. The official gene symbol is SERPINC1. The kits can detect several species variants of the protein, including: human, mouse, rat, chicken, primate, guinea pig, and other mammalian. The protein, with a mass of 52.6 kDa and length of 464 residues, is reported to be secreted. It is a member of the Serpin family and may be known by other names, including: ATIII, AT3D, serpin peptidase inhibitor clade C member 1, serine (or cysteine) proteinase inhibitor clade C (antithrombin) member 1, antithrombin III isoform, and antithrombin-III, and ATIII-T1.