Halpern E P, Bordens R W
Clin Chem. 1979 Sep;25(9):1561-3.
We describe a method for directly measuring free thyroxine in human serum. Antibody to thyroxine was encapsulated within a semipermeable nylon membrane that excludes substances of relative molecular mass greater than 20,000. The microencapsulated antibody was then presaturated with [125I]thyroxine. Serum incubated with the microcapsules initiated a displacement reaction between free thyroxine and [125I]thyroxine bound to the antibody. The displaced thyroxine was separated from the bound thyroxine by centrifugation and the concentration of free thyroxine determined from a standard curve prepared by use of known amounts of free thyroxine. The within-day coefficient of variation for two control samples was 8.8 and 6.8%; day-to-day precision for the same material was 12.5 and 13.5%. Lipemia, icterus, or hemoglobin had no adverse effect. Interlaboratory evaluation of the procedure revealed no significant difference in mean values for 20 speciments (p greater than 0.05).
我们描述了一种直接测量人血清中游离甲状腺素的方法。甲状腺素抗体被包裹在半透性尼龙膜内，该膜可排除相对分子质量大于20,000的物质。然后用[125I]甲状腺素对微囊化抗体进行预饱和。与微囊一起孵育的血清引发了游离甲状腺素与结合在抗体上的[125I]甲状腺素之间的置换反应。通过离心将置换出的甲状腺素与结合的甲状腺素分离，并根据使用已知量的游离甲状腺素制备的标准曲线确定游离甲状腺素的浓度。两个对照样品的日内变异系数分别为8.8%和6.8%；同一材料的日间精密度分别为12.5%和13.5%。脂血、黄疸或血红蛋白均无不良影响。该方法的实验室间评估显示，20个样本的平均值无显著差异（p>0.05）。
