Serum Protein-Bound Iodine Estimation in Thyroid Disorders

Abstract

216amount to more than 50 % of the wet weight of the leucocytes.For the modified method, thin tubes were made from 250 gauge polythene sheet. The leucocytes were centrifuged into its conical tip and the rest of the tube was cut away. Excess extracellular material which overlaid the cell mass was blotted off. The results of analysis showed minimal contamination and gave the expected intracellular pattern for sodium and potassium.A polythene tube has other advantages. Its light weight reduces weighing errors. When sealed all round, it minimises loss of water by evaporation from the cell mass. It can be conveniently stored in the deep freeze, dispatched through the post for neutron activation analysis, or ashed as whole without need for transfer of cells.The Measurement of Chelatable Body Iron J. FIELDING PADDINGTON GENERAL HOSPITAL, LONDONThe differential ferrioxamine test is a simple method for the measurement of in vivo chelation of body iron by desferrioxamine.A single six hour specimen of urine is obtained after intravenous desferal, accompanied by li9Fe-ferrioxamine. Two values are measured: Ed, the excretion of ferrioxamine derived from body iron by chelation and Fex, the excretion of ferrioxamine from a known intravenous dose. The data enables in vivo chelation of iron (Fv) to be calculated by simple proportion.Desferrioxamine chelation proceeds for about half an hour after injection.The results in normal subjects, in cases with known high iron stores and in cases of iron deficiency anremia were described. High, normal and low body iron status have been differentiated.Fv values in the higher ranges obtained in iron storage diseases and in heemolytic states, are differentiated by the pattern of excretion: high Fd values and low Fex values respectively.The results suggest that there are two main sources of chelatable body iron-(a) stores as ferritin-hremosiderin, (b) iron newly released from hrem, in a more readily chelatable form.The variable chelatability of different sources of body iron may be significant for the understanding of iron metabolism. It may explain for instance, preferential utilisation of iron released from red cells or absorbed from the intestine, rather than storage iron, in the biosynthesis of heem, The work carried out over the past four years blood by iodine-containing preparations used at the Protein-Bound Iodine Reference Labora-for therapeutic or radiological purposes. tory~t the Staffordshire General Infirmary was A survey of 600 adults gave statistically a descnbed.normal range for PBI of 3'7-7,0 ILg/IOO ml., low The estimation of the iodine contained in values being found in hypothyroidism and high thyroxine and tri-iodothyronine (serum PBI) re-values in thyrotoxicosis. Using these PBI levels fleets the level of the circulating thyroid hor-as the sole criterion of diagnosis, 96·2 %of normal mones, The method used is that of Acland (1957) people, 95·8 %of thyrotoxic and 100% of hypoand requires technical competence and care; a . thyroid patients are correctly assessed. In pracsepara...