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Alternative Names Return to topVitamin B12 absorption test
Definition Return to top
The Schilling test is used to determine whether the body absorbs vitamin B12 normally.
How the Test is Performed Return to top
This test may be performed in four different stages to find the cause of low vitamin B12 levels.
Stage I: You will get two doses of vitamin B12 (cobalamin). The first dose is taken by mouth. The second dose is a radioactive form of B12. It is given as a shot 2 - 6 hours later. You will need to collect your urine over the next 24 hours, and deliver it to a lab or your doctor's office. The urine will be checked to see if you are absorbing vitamin B12 normally. For information on collecting the urine sample, see: 24-hour urine collection
If Stage I is abnormal, Stage II may be done 3 - 7 days later.
Stage II: You are given radioactive B12 along with intrinsic factor. Intrinsic factor is a protein produced by cells in the stomach lining. The body needs it so the intestines can absorb vitamin B12 efficiently.
Stage II of the test can tell whether low vitamin B12 levels are caused by problems in the stomach that prevent it from producing intrinsic factor.
If a Stage II test is abnormal, a Stage III test is performed.
Stage III: This test is done after you have taken antibiotics for 2 weeks. It can tell whether abnormal bacterial growth has caused the low vitamin B12 levels.
Stage IV: This test determines whether low vitamin B12 levels are caused by problems with the pancreas. With this test, you will take pancreatic enzymes for three days, followed by a radioactive dose of vitamin B12.
How to Prepare for the Test Return to top
How the Test Will Feel Return to top
The injection of vitamin B12 may sting.
Why the Test is Performed Return to top
The Schilling test is performed to check vitamin B12 absorption and to evaluate patients for pernicious anemia.
Additional conditions under which the test may be performed:
Normal Results Return to top
Urinating 8 - 40% of the radioactive vitamin B12 within 24 hours is normal.
Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean Return to top
Low vitamin B12 levels can cause megoblastic anemia.
If there is a problem with the stomach's ability to make intrinsic factor, Stage I of the test will be abnormal and Stage II will be normal.
Both the Stage I and II Schilling tests will be abnormal in people who have problems absorbing vitamin B12 and intrinsic factor in the small intestine.
Abnormal results may be due:
Risks Return to top
References Return to top
Antony AC. Megaloblastic anemias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 170.Update Date: 2/13/2009 Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.