Dual isotope Schilling test for measuring absorption of food-bound and free vitamin B12 simultaneously.
A prototype food-bound vitamin B12 (food-B12) absorption test has been developed in which 57Co-B12 was incorporated in vitro into egg yolk (yolk-B12) and served to volunteers in 50-g cooked portions together with toast and coffee for breakfast. Six hours later, 1 mg nonlabeled B12 was given intramuscularly and 24-hour urine was collected for radioactivity measurement. In separate tests, the absorption of yolk-B12 and crystalline 57Co-B12 was equally poor in patients with pernicious anemia. However, in patients with simple gastric achlorhydria and those who had undergone gastric surgery, the assimilation of yolk-B12 was impaired greatly, whereas the absorption of crystalline radio-B12 was normal. Egg yolk labeled with 58Co-B12 was administered together with crystalline 57Co-B12 in a dual isotope test with results similar to those obtained when the tests were prepared separately. This yolk-58Co-B12 test with its ability to detect malabsorption of food-B12 may be considered as an addition to the first part of the Schilling test.
D000042:Absorption; D000126:Achlorhydria / Q000150:complications; D000752:Anemia, Pernicious / Q000150:complications; D003037:Cobalt Radioisotopes; D004529:Egg White; D004530:Egg Yolk; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D012546:Schilling Test / Q000379:methods*; D013270:Stomach / Q000601:surgery; D014805:Vitamin B 12 / Q000008:administration & dosage* / Q000652:urine; D014806:Vitamin B 12 Deficiency / Q000150:complications / Q000175:diagnosis* / Q000652:urine
D003037:Cobalt Radioisotopes; D014805:Vitamin B 12