A SIMPLIFIED METHOD FOR THE DETERMINATION OF THE PROTEIN-BOUND BLOOD IODINE AND ITS CLINICAL APPLICATION*†

Abstract

A shorter and simpler method of determining the protein-bound blood I has been attained by developing a procedure which requires no transfer of material during the entire analysis. This necessitates an apparatus of especially constructed glassware. 3 ml. of serum are fractionated in a 250-ml. reagent flask by use of the Somogyi reagent. This flask is centrifuged in an International, size 2, centrifuge. The supernatant fluid containing the soluble "inorganic" I is poured off and read in the colorimeter directly. The protein precipitate containing the physiologically significant protein-bound iodine remains in the 250 ml. reagent flask and is oxidized by the chromic acid procedure. The same flask fits a distillation assembly. The iodine is then released by phosphorous acid and collected directly in a colorimeter tube, which also fits the distillation assembly. The quantity of iodine is detd. by its catalytic effect on the rate of reaction between ceric sulfate and arsenious acid. A well-trained technician can make an analysis in less than 3 hrs. and about 10 analyses during an 8-hr. day. The avg. deviation is [plus or minus] 5%. Since the method is essentially a closed procedure, contamination has been practically eliminated. It yields results which have a good clinical correlation.