CLINICAL APPLICATION OF THE THIOCHROME REACTION IN THE STUDY OF THIAMIN (VITAMIN B,) DEFICIENCY *

A CHEMICAL method for the estimation of thiamin (vitamin Bi), should have the advantages, as compared to biological assay, of speed, accuracy, cheapness, and ease of performance. The great advantage of biological assay is definite specificity. However, under well controlled conditions the uncertainties of chemical assay may become negligible. Of the several methods proposed for the chemical estimation of thiamin, the thiochrome method of Jansen * has received the most attention. Re-cently, the method of Prebluda and McCollum 2 as modified by Melnick and Field3 has been shown to possess a high degree of specificity and accuracy, but the technic as described seems too complex for ordinary clinical purposes. Schultz et al.4 have developed a fermentation test for vitamin Bx which ap-parently is rapid and sufficiently specific for most purposes. The phycomyces growth method of Schopfer,5 applied to various ma-terials by Meiklejohn,6 Bonner,7 and Rowlands,8 may prove to be of con-siderable value as a comparatively simple method of biological assay suitable for clinical investigation. The purpose of this paper is to relate experiences with the thiochrome method as applied to urine in study of the metabolism of thiamin in normal and thiamin deficient subjects, with special attention to the possibility of diagnosis of thiamin deficiency states. Using the bradycardia method of bioassay, Harris and his associates 9 showed that the urinary excretion of thiamin depends upon the amount in-gested; that subjects on adequate diets excrete in the urine more thiamin than patients with varying degrees of deficiency. In 24 hours normal sub