1973 Volume 22 Issue 12 Pages 701-706
This is a report on the basical and clinical study of Thyopac 4 method developed by RCC, which is a simple method of measuring thyroxine (T4) in the blood.
The procedure of Thyopac 4 was easier than that of Res-O-Mat T4 and Tetrasorb T4 method, and automatic counter was available to this method. Stable values were obtained about 30 to 40 minutes of incubation time at about 23°C room temperature. Concerning variation of the measurement values σ was ±12.3%. Normal values ranged from 4.7 to 12.9 μg/dl. These values were compared with Res-O-Mat T4 values, thyroidal uptake of 131I and Thyopac 3 values measured at the same time. The correlation and the clinical value were as follows: Thyopac 4 value was well correlated with Res-O-Mat T4 value and Thyopac 4/Res-O-Mat T4=0.938±0.02 with the correlation rate of 89.3%. Thyopac 4 value was also well correlated with the 24-hour thyroidal uptake of 131I with the correlation rate of 82.7%. In the correlation between Thyopac 4 value and Thyopac 3 value Katayama line was determined, of which upper line was θ=∠35°, and lower line was μ=∠11°18'. Various diseases were divided by these lines. When we assume Thyopac 4/Thyopac 3=Thyopac FTI value, the correlation between Thyopac 4 value and Thyopac FTI value was significant with the correlation rate of 94.0%, and the correlation between Thyopac FTI value and the 24-hour thyroidal uptake of 131I was also significant with the correlation rate of 84.2%.
As described above, the measurement of thyroxine in the blood by Thyopac 4 was very simple and valuable from both basical and clinical points of view.