An enzyme immunoassay for intrinsic factor in urine

An enzyme immunoassay for intrinsic factor has been used on urine. The assay can measure intrinsic factor in native urine from healthy people and from patients with pernicious anaemia with no antibodies. The urinary intrinsic factor concentration in healthy individuals ranged from 40 to 54 pmol/l. Intrinsic factor antibodies, demonstrated by testing the recovery of added intrinsic factor, interfered with the assay. Cobalamin at high concentrations also affected the assay result. A low intrinsic factor concentration or the presence of antibodies to intrinsic factor was found in the urine of individuals with pernicious anaemia.