Anti-Intrinsic Factor antibodies are used in antigen-specific immunodetection in biological samples. The target Intrinsic Factor is a known alias name of the protein cobalamin binding intrinsic factor, encoded by the CBLIF gene in humans. This 417-amino acid residue protein is reported to promote absorption of the essential vitamin cobalamin (Cbl) in the ileum. The protein is secreted and features glycosylated post-translational modifications. It is reported to be expressed in the stomach and testis. Other synonyms for Intrinsic Factor include GIF, GIF, and IF.