Giovanella Luca, Keller Franco, Ceriani Luca, Tozzoli Renato
Department of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Clin Chem Lab Med. 2009;47(8):952-4. doi: 10.1515/CCLM.2009.230.
To examine the prevalence of significant interference from heterophile antibodies (HAb) in the measurement of serum thyroglobulin (Tg), we evaluated a large cohort of samples from patients with differentiated thyroid carcinoma (DTC).
Serum Tg measurements were performed in 406 serum samples before and after incubation of each serum sample in heterophile-blocking tubes (HBT) at room temperature for 1 h. We calculated the difference between the original Tg value and the value obtained after HBT treatment. We considered any sample showing an absolute percent difference >3 SD from the mean percent difference as being affected by HAb interference.
We identified five patients (1%) as showing interference from HAb. Of these, three (60%) showed a false positive or falsely increased Tg concentration without any recurrence following clinical work-up; two (40%) showed a false negative or falsely reduced Tg levels, and metastases were detected in both cases by imaging procedures.
HAb may increase as well as reduce the measured Tg in a significant number of patients. A positive HAb interference should be suspected if Tg elevation does not fit the clinical pictures. A negative interference is a more challenging problem because increases in Tg generally occur as the first sign of recurrence of DTC. Therefore, treatment using HBT tubes of all sera referred for Tg measurement should be considered in order to prevent both unwarranted investigations or therapy, and delayed diagnosis of recurrence in patients affected by DTC.
为了研究嗜异性抗体（HAb）在血清甲状腺球蛋白（Tg）检测中显著干扰的发生率，我们评估了一大组分化型甲状腺癌（DTC）患者的样本。
对406份血清样本在室温下于嗜异性阻断管（HBT）中孵育1小时前后进行血清Tg检测。我们计算了原始Tg值与HBT处理后获得的值之间的差异。我们将任何显示绝对百分比差异大于平均百分比差异3个标准差的样本视为受HAb干扰影响。
我们确定有5名患者（1%）显示受HAb干扰。其中，3名患者（60%）显示Tg浓度出现假阳性或假性升高，临床检查后无任何复发情况；2名患者（40%）显示Tg水平出现假阴性或假性降低，且这两例通过影像学检查均检测到转移灶。
在相当数量的患者中，HAb可能会使检测到的Tg升高或降低。如果Tg升高与临床表现不符，则应怀疑存在阳性HAb干扰。阴性干扰是一个更具挑战性的问题，因为Tg升高通常是DTC复发的首个迹象。因此，为了避免不必要的检查或治疗以及DTC患者复发的延迟诊断，对于所有送检进行Tg检测的血清，应考虑使用HBT管进行处理。
