Schilling test is used for -

Ans. is 'c' i.e., Vitamin B12 absorption [Ref: Clinical diagnosis and management by the laboratory method"Schilling test is used for l it B12 absorption "Schilling test Step 1o Administer an intramuscular injection of Vitamin Bl2This will saturate the vitamin B12 receptors because otherwise, the body would be hungry for the oral dose of vitamin B12 and radiolabelled vitamin B12 will not appear in urine even if there is no abnormality in vitamin B12 absorption.Step 2o Give a radiolabeled oral dose of vitamin BI2If the vitamin B 12 absorption is normal the radiolabelled vitamin B 12 would appear in the urine. In that case, Vitamin B12 deficiency is believed to be due to dietary deficiency.If the vitamin B 12 does not appear in the urine malabsorption of Vitamin B12 is suspected. It has to find out whether its due to pernicious anemia or some other cause.Step 3o Sow, administer intrinsic factor along with radiolabelled Vitamin BI2If vitamin B12 appears in the urine then the diagnosis is pernicious anemia.If the Vitamin Bl 2 still does not appear in the urine then it is a case of malabsorption but not due to pernicious anemia and most commonly due to ileal resection or small bowel infection and bacterial overgrowth.