Laurberg P, Pedersen K M
Second University Clinic of Internal Medicine, Aarhus Kommunehospital, Denmark.
Scand J Clin Lab Invest. 1987 Nov;47(7):685-9.
A new thyroglobulin (Tg) assay employing polyethylene glycol (PEG) for separation of free and antibody bound [125I]Tg is described. By choosing a suitable PEG concentration the non-specific precipitation of free [125I]Tg was kept low while both [125I]Tg bound to rabbit anti-Tg immunoglobulins and to human Tg autoantibodies were precipitated. For all sera a 'blank' incubation with no rabbit anti-Tg immunoglobulins was run in parallel with the assay tubes. Hence any interference of Tg autoantibodies would be detected. A two-phase incubation gave a very low detection limit of 0.2 microgram/l. The inter-assay coefficient of variation was 9.4% and the intra-assay coefficient of variation was 5.6%. Dilution curves of normal sera were parallel to the standard curve and Tg standards added to normal sera were recovered quantitatively. Twelve out of 60 normal sera from the Randers area contained Tg autoantibodies. The average serum Tg in the 48 sera without antibody was 44.6 +/- 5.2 micrograms/l (SEM).
描述了一种新的甲状腺球蛋白（Tg）检测方法，该方法采用聚乙二醇（PEG）分离游离的和与抗体结合的[125I]Tg。通过选择合适的PEG浓度，游离[125I]Tg的非特异性沉淀保持在较低水平，而与兔抗Tg免疫球蛋白和人Tg自身抗体结合的[125I]Tg均被沉淀。对于所有血清样本，在检测管平行运行一个不添加兔抗Tg免疫球蛋白的“空白”孵育。因此，可以检测到Tg自身抗体的任何干扰。两相孵育的检测限非常低，为0.2微克/升。批间变异系数为9.4%，批内变异系数为5.6%。正常血清的稀释曲线与标准曲线平行，添加到正常血清中的Tg标准品可被定量回收。来自兰讷斯地区的60份正常血清中有12份含有Tg自身抗体。另外48份无抗体血清的平均血清Tg为44.6±5.2微克/升（标准误）。
