Schilling test

Part 1

0.65 uCi Co-57 B-12 + 1000 ug unlabelled B-12 injection

Unlabelled B-12 saturates all the liver and blood binding sites thus promoting urinary excretion of the labeled vitamin B-12.

• normal 24-hr specimen of 1 liter: 10-40% of administered dose
• excretion < 7% suggests pernicious anemia or malabsorption

Part 2

same as above plus intrinsic factor

low urinary excretion indicates malabsorption

• sprue
• Crohn disease
• blind loop syndrome

© 2002, C.E. Kahn, Jr.
2002-04-18