Iodine Contamination in Iodometric Measurements of Thyroid Hormones

Abstract

The incidence of iodine contamination in serum protein-bound iodine requests was assessed by comparison of results with those of a method using anion-exchange columns to improve specificity. The precision, accuracy, and specificity of the column method was found to be adequate, abnormal elution patterns generally warning where results were affected by contamination. The proportion of discrepancies in results and diagnoses between the two tests showed the protein-bound iodine to be unsatisfactory as a sole test of thyroid hormone levels, or in hypothyroidism, even as a screening test.