The estimation of vitamin B1 in blood

Abstract

Following the work of Schopfer with the fungus Phycomyces, Meiklejohn descr. a method of estimating vit. B1 in blood. His conclusion that it provides a quantitative estimate of the true vit. B1content of the blood has not been confirmed. Under given conditions blood always contains substances that affect the growth of the fungus. Hydrolysed casein is the most satisfactory source of N that has been found. By means of this it can be shown that sources of N in the blood affect the growth of the fungus even in presence of optimal concs, of asparagine. Under the conditions of the test the addition to blood of small amts. of vit. B1 usually produces a greater growth than expected, and addition of excess vit. invariably does so. The method is known not to be specific for vit. B1. The importance is emphasized of carefully controlling factors such as the temperature of autoclaving and the length of time the blood is stored. If the possible sources of error are borne in mind and controlled as far as possible, the method is valuable for comparing the apparent vit. B1 in different samples of blood.