Department of Laboratory Medicine, Cliniques Universitaires Saint-Luc and Université Catholique de Louvain, Brussels, Belgium.
Service d'Endocrinologie et Nutrition, Cliniques Universitaires Saint-Luc and Université Catholique de Louvain, Brussels, Belgium.
Endocr Rev. 2018 Oct 1;39(5):830-850. doi: 10.1210/er.2018-00119.
Automated immunoassays used to evaluate thyroid function are vulnerable to different types of interference that can affect clinical decisions. This review provides a detailed overview of the six main types of interference known to affect measurements of thyroid stimulating hormone (TSH), free thyroxine (T4) and free triiodothyronine (T3): macro-TSH, biotin, antistreptavidin antibodies, anti-ruthenium antibodies, thyroid hormone autoantibodies, and heterophilic antibodies. Because the prevalence of some of these conditions has been reported to approach 1% and the frequency of testing for thyroid dysfunction is important, the scale of the problem might be tremendous. Potential interferences in thyroid function testing should always be suspected whenever clinical or biochemical discrepancies arise. Their identification usually relies on additional laboratory tests, including assay method comparison, dilution procedures, blocking reagents studies, and polyethylene glycol precipitation. Based on the pattern of thyroid function test alterations, to screen for the six aforementioned types of interference, we propose a detection algorithm, which should facilitate their identification in clinical practice. The review also evaluates the clinical impact of thyroid interference on immunoassays. On review of reported data from more than 150 patients, we found that ≥50% of documented thyroid interferences led to misdiagnosis and/or inappropriate management, including prescription of an unnecessary treatment (with adverse effects in some situations), inappropriate suppression or modification of an ongoing treatment, or use of unnecessary complementary tests such as an I123 thyroid scan. Strong interaction between the clinician and the laboratory is necessary to avoid such pitfalls.
用于评估甲状腺功能的自动化免疫分析容易受到各种类型的干扰，从而影响临床决策。本综述详细介绍了已知会影响促甲状腺激素（TSH）、游离甲状腺素（T4）和游离三碘甲状腺原氨酸（T3）测量的六种主要类型的干扰：巨 TSH、生物素、抗链霉亲和素抗体、抗钌抗体、甲状腺激素自身抗体和异嗜性抗体。由于这些情况的患病率据报道接近 1%，且检测甲状腺功能障碍的频率很重要，因此问题的规模可能非常大。每当出现临床或生化差异时，都应怀疑是否存在潜在的甲状腺功能检测干扰。通常需要通过额外的实验室测试来识别这些干扰，包括方法比较、稀释程序、阻断试剂研究和聚乙二醇沉淀。基于甲状腺功能测试改变的模式，为了筛查上述六种类型的干扰，我们提出了一种检测算法，这有助于在临床实践中识别这些干扰。该综述还评估了甲状腺干扰对免疫分析的临床影响。对 150 多名患者的报告数据进行审查后，我们发现≥50%的有记录的甲状腺干扰导致误诊和/或不适当的治疗，包括不必要的治疗（在某些情况下会产生不良反应）、不适当的抑制或修改正在进行的治疗，或使用不必要的补充测试，如 I123 甲状腺扫描。临床医生和实验室之间需要进行强有力的互动，以避免这些陷阱。
