"Thyrolute"キットによるFree T4 Equivalent(FTE)並びに"Trilute""Tetralute"キットによるFree T4 Index(FTI)の臨床的評価

Abstract

Usefulness of a new dual competitive protein binding analysis for determination of total thyroxine and free thyroxine equivalent (FTE), "Thyrolute kit" was clinically evaluated. And at the same time, usefulness of the free thyroxine index (FTI) obtained by using "Trilute" and "Tetralute" kit was evaluated. The sera from 97 cases with various conditions were used for the study. Further, using a part of these serum samples, T_3 uptake and T_4 were determined by "Triosorb" and "Tetrasorb" kit respectively. T_4 values obtained by "Thyrolute" correlated well with those by "Tetralute" (γ=0.880). FTE values obtained were as follows : normal subjects (44 cases) 1.11±0.27,hyperthyroidism (20 cases) 2.83±0.47,hypothyroidism (17 cases) 0.47±0.19 and pregnant women (7 cases) 1.23±0.12. FTI values on the same sera were as follows : normal subjects (44 cases) 9.38±2.58,hyperthyroidism (20 cases) 24.70±4.49,hypothyroidism (17 cases) 2.97±1.28 and pregnant women (7 cases) 6.60±0.57. In both of the two indices, a highly significant difference was observed between the values in the patients with hyperthy roidism and those in normal subjects but slight overlapping was found between the values in normal subjects and those in the patients with hypothyroidism. The indices of the patients with abnormal TBG concentration fell within the normal range. A good correlation was observed between FTE and FTI (γ=0.940). FTI calculated from Triosorb and Tetrasorb values correlated well with the FTI and the FTE obtained by the methods described above, (γ=0.890 and 0.885). Although FTI was found to be useful in evaluating various thyroid conditions, it requires the use of two kits. Thyrolute kit, on the other hand, was shown to give reliable data on T_4 concentration and FTF in a single kit, and was considered to be useful in clinical practice.