Schilling-Test

With the Schilling test (after Robert F. Schilling 1953) the absorption of vitamin B12 can be determined in the small intestine.

Implementation

The patient is asked to empty the bladder. With the beginning of the experiment, the 24 -hour collection of urine begins. The patient is administered orally by 57Co radiolabeled vitamin B12 1 ug. The labeled vitamin B12 is normally absorbed in the small intestine into the blood. Two hours after the oral administration of the labeled vitamin patient 1000 micrograms of unlabeled vitamin B12 can be injected intramuscularly. Thereby, the labeled vitamin is displaced from the binding proteins prevent deposition in the liver and excretion in the urine provoked. Then, the amount present is measured by radioactive vitamin B12 in the urine collected. Important in the implementation is the discontinuation of all medications that may interfere with the absorption of vitamin B12. A sufficient distance from other studies with radiolabeled isotopes must be guaranteed. Iodinated contrast agents may reduce the radiation from 57Co.

Assessment

• In a healthy patient at least 6% of radiolabeled vitamin B12 are excreted.
• In the absence of intrinsic factor, which is needed for the absorption of vitamin B12, the proportion of excreted urinary 57Co -labeled vitamin B12 is reduced because much of it is excreted in the stool. In this case, may be repeated with the addition of an intrinsic factor of the test after a few days.
• When the function of the small intestine is affected ( malabsorption ), and the fraction is also reduced. A new test with intrinsic factor does not show a different result.
• Also, an overgrowth of the small intestine with bacteria can lead to a reduction of the Group, as well as various bacteria vitamin B12 can record.
• Renal failure may delay the precipitation of vitamin B12.