Vitamin B ₁₂ Concentrations of Serum and Urine in the First 72 Hours After Intramuscular Injections of the Vitamin

Abstract

The vitamin B12 concentrations of serum and urine can be assayed microbiologically with Euglena gracilis as test organism (Ross, 1950, 1952; Mollin and Ross, 1952). The mean vitamin B12 concentration of the serum of normal sub- jects was found to be 350 ,qL4g./ml. The lower limit of the range in normal subjects was 100 muscular dose of vitamin B12 after a first injection of 40 jig., the interval between injections being on July 18, 2023 by guest.