Schilling test
Vitamin B12 absorption testThe Schilling test can determine whether the body absorbs vitamin B12 normally. It helps assess the cause of vitamin B12 deficiency. This test is rarely, if ever, done today.
References
Höegenauer C, Hammer HF. Maldigestion and malabsorption. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 104.