Conventional and dual competitive binding analyses of thyroxine using the Thyopac - 4 kit ' SATOSHI HAMADA

sYNoPsis A simple method is described for the simultaneous determinations of thyroxine and the effective thyroxine ratio (ETR) using a single kit of Thyopac-4. Thyopac ETR values obtained were 1-00 ± 0'03 for normal subjects; 1 22 ± 0 11 for hyperthyroid; 0-87 ± 0-04 for hypothyroid; and 1 02 ± 0'05 for pregnant women. Cases with TBG deficiency and the nephrotic syndrome indicated normal values. The value (x) was correlated significantly (y = + 0-961) with the free Thyopac index (y), representing a regression equation of y = 71*7x2 88-4x + 24x2. Thyopac ETR was shown to be useful in differentiating normal thyroid states from abnormal, irrespective ofchanges in T4-binding globulin (TBG). Further, the T4 value obtained simultaneously made it possible to detect changes in the TBG level by noting an inconsistent value for the effective thyroxine ratio.