Preferred Specimen(s) 1 mL serum
Transport Container Plastic screw-cap vial
Transport Temperature Refrigerated (cold packs)
Reject Criteria Grossly hemolysed
Methodology Immunoassay
Clinical Significance Intrinsic Factor, produced by cells lining the stomach, binds vitamin B12 (cyanocobalamin) to facilitate absorption of the vitamin. Blocking antibody impedes the action of Intrinsic Factor as observed in approximately half of the patients who develop pernicious anemia.