Schilling test
Alternative names:
vitamin B12 absorption test
Normal values:
Excretion of 8 to 40% of the radioactive vitamin B12 within 24-hours is normal.
What abnormal results mean:
Pernicious anemia results when absorption of vitamin B12 is inadequate. This may be caused by a primary malabsorption problem; possibly caused by an inflammation in the intestines, a deficiency of vitamin B12 in the diet, or a deficiency of intrinsic factor. The most common cause of intrinsic factor deficiency is surgical resection of part of the stomach as treatment for peptic ulcer. Other causes include genetic deficiency and development of an antibody that reacts against the intrinsic factor. Patients who have pernicious anemia from lack of intrinsic factor will have abnormal results on the 1-stage Schilling test (that is, the first test with out intrinsic factor) and normal results when on 2-stage Schilling test (that is, the second test performed about 1 week after the first and after intrinsic factor is given). Patients with malabsorption from an intestinal source will have abnormal results from both the 1- and 2-stage Schilling tests.
Abnormal 1- and 2-stage Schilling tests may indicate: Lower-than-normal amounts of vitamin B12 absorption may indicate: - biliary disease, resulting in malabsorption (inadequate absorption of nutrients from the intestinal tract)
- intestinal malabsorption (for example, related to sprue or celiac disease)
- liver disease (causing malabsorption)
- pernicious anemia
Additional conditions under which the test may be performed:
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