Provided below are ELISA kits targeting haptoglobin, a human protein encoded by HP. This protein is 406 amino acids long, with a mass of 45.2 kDa, and is a member of the Peptidase S1 family. 2 isoforms have been identified. This is reported to be a secreted protein. There is a noted implication in Anhaptoglobinemia. Other alias names for this protein include: binding peptide, haptoglobin alpha(1S)-beta, haptoglobin alpha(2FS)-beta, haptoglobin alpha polypeptide, zonulin, BP, and HP2ALPHA2. ELISA kits are available that are reactive to human, mouse, rat, bovine, chicken, primate, guinea pig, fish, plant, and other mammalian variants of the target antigen.