Used in biomedical research to detect and quantify intrinsic factor (IF) antibodies of the (S) subtype in rat serum or plasma samples. This kit supports studies related to autoimmune gastritis and pernicious anemia models in rats by enabling specific measurement of inhibitory antibodies that interfere with the vitamin B12 absorption pathway. It is particularly useful in immunoassay development, preclinical evaluation of gastrointestinal autoimmunity, and monitoring immune responses in experimental animal models. The assay aids in understanding the pathogenesis of vitamin B12 deficiency and assessing therapeutic interventions targeting the intrinsic factor-cobalamin complex.