Schilling test is Abnormal in:

Answer is A (Intrinsic factor deficiency) Shilling's test is typically done to determine the cause of cobalamine malabsorption (Vitamin B12 malabsorption) Vitamin B12 absorption (Schilling) test is typically used to diagnose conditions in which intrinsic factor (IF) may be absent, such as pernicious anemia or gastric atrophy. A diagnosis of Intrinsic factor deficiency can be established if radiolabelled cobalamine (Vitamin B12) appears in urine after administration of Intrinsic factor. Since cobalamine absorption requires multiple steps including gastric, pancreatic and ileal processes, the Schilling test can also be used to assess the integrity of these other organs. Dietary vitamin B 12 is bound in the stomach to an endogenous protein called R protein. Pancreatic enzymes degrade the R protein in the proximal small bowel and lower its affinity for vitamin B12 resulting in the rapid transfer of B 12 to IF; The IF-B12 Complex continues to the terminal ileum, where it binds to specific receptors on the surface of the epithelial cells. Thus lack of intrinsic factor, lack of sufficient pancreatic enzymes (pancreatic exocrine dysfunction) or presence of terminal heal mucosal disease may all result in abnormal vitamin B12 excretion.