Vitamin B12 absorption studies using radioactive vitamin B12: comparison of whole body retention and urinary excretion after flushing dose (Schilling's test).

Vitamin B-12 absorption of 12 healthy young male subjects was determined by using labelled vitamin B-12 by Schilling's test and whole body retention test. The whole body retention test was performed first using low energy Co57 isotope and a week later, Schilling's test was performed. Whole body retention showed a mean absorption of 56.5% while Schilling's test showed mean absorption of 16.9% in the same subjects. Data supports the whole body retention test being more accurate.