tract, it will pass into the urine. The patients urine is then collected over the next 24 hours to assess the absorption. Normally, the ingested radiolabeled vitamin B12 will be absorbed into the body. Since the body already has liver receptors for transcobalamin/vitamin B12 saturated by the injection, much of the ingested vitamin B12 will be excreted in the urine. A normal result shows at least 10% of the radiolabeled vitamin B12 in the urine over the first 24 hours. In patients with pernicious anemia or with deficiency due to impaired absorption, less than 10% of the radiolabeled vitamin B12 is detected.The normal test will result in a higher amount of the radiolabeled cobalamin in the urine because it would have been absorbed by the intestinal epithelium, but passed into the urine because all hepatic B12 receptors were occupied. An abnormal result is caused by less of the labeled cobalamin to appear in the urine because it will remain in the intestine and be passed into the feces. Stage 2: vitamin B12 and intrinsic factor
If an abnormality is found, i.e. the B12 in the urine is only present in low levels, the test is repeated, this time with additional oral intrinsic factor. If this second urine collection is normal, this shows a lack of intrinsic factor production. This is by definition pernicious anemia.
A low result on the second test implies abnormal intestinal absorption (malabsorption), which could be caused by coeliac disease, biliary disease, Whipples disease, small bowel bacterial overgrowth syndrome, fish tapeworm infestation (Diphyllobothrium latum), or liver disease. Malabsorption of B12 can be caused by intestinal dysfunction from a low vitamin level in-and-of-itself (see below), causing test result confusion if repletion has not been done for some days previously. Stage 3: vitamin B12 and antibiotics
This stage is useful for identifying patients with bacterial overgrowth syndrome. The physician will provide you a course of 2 weeks of antibiotics to eliminate any possible bacterial overgrowth and repeat the test to check whether radio-labeled Vitamin B12 would be found in urine or not. Stage 4: vitamin B12 and pancreatic enzymes
This stage, in which pancreatic enzymes are administered, can be useful in identifying patients with pancreatic insufficiency. The physician will give you 3 days of pancreatic enzymes followed by repeating the test to check if radio-labeled Vitamin B12 would be detected in urine. Combined stage 1 and stage 2
In some versions of the Schilling test, B12 can be given both with and without intrinsic factor at the same time, using different cobalt radioisotopes 57Co and 58Co, which have different radiation signatures, in order to differentiate the two forms of B12. This is performed with the Dicopac kitset. This allows for only a single radioactive urine collection.