Piticchio Tommaso, Chiardi Isabella, Tumminia Andrea, Frasca Francesco, Rotondi Mario, Trimboli Pierpaolo
Department of Clinical and Experimental Medicine, Endocrinology Section, University of Catania, Catania, Italy.
Department of Medicine and Surgery, University of Enna "Kore", Enna, Italy.
Clin Endocrinol (Oxf). 2025 Mar;102(3):235-244. doi: 10.1111/cen.15179. Epub 2024 Dec 19.
Macro-thyroid-stimulating hormone (macro-TSH) is a complex formed by monomeric TSH with anti-TSH antibodies, causing falsely elevated TSH levels and potential misdiagnosis of hypothyroidism. Identification of macro-TSH is essential for proper treatment and patient follow-up. Its diagnostic gold standard is gel filtration chromatography (GFC), which is very expensive, time-consuming, and rarely available. Polyethylene glycol (PEG) precipitation is more accessible and inexpensive. The aim of the study was to review evidence on PEG precipitation for the detection of macro-TSH to standardize its application in clinical practice.
According to PRISMA guidelines, we conducted up to August 2024 a comprehensive search of PubMed and Scopus databases, using terms related to macro-TSH and PEG precipitation.
We included 23 studies with 4476 subjects, encompassing 10 observational studies and 13 case series/reports. All studies showed a low risk of bias. They were conducted in tertiary centres and included newborns to elderly subjects. The most of evidence about the procedure has been achieved with PEG concentrations of 12.5%. The PEG-precipitable TSH of the macro-TSH cases was always higher than 75% ranging on average from 81% to 90%. No-macro-TSH cases (controls) showed a PEG-precipitable TSH percentage ranging from 44.1% to 61.8%.
PEG precipitation can be taken into account as a useful diagnostic tool for macro-TSH. However, it is necessary to perform PEG precipitation in cases with a highly suspicious clinical picture and at the same time perform all available ancillary tests. PEG-precipitable TSH > 75% can be considered a reliable diagnostic threshold for macro-TSH cases.
巨甲状腺刺激激素（macro-TSH）是由单体促甲状腺激素（TSH）与抗TSH抗体形成的复合物，可导致TSH水平假性升高，并可能导致甲状腺功能减退的误诊。识别macro-TSH对于正确治疗和患者随访至关重要。其诊断金标准是凝胶过滤色谱法（GFC），该方法非常昂贵、耗时且很少可用。聚乙二醇（PEG）沉淀法更易获得且成本较低。本研究的目的是回顾关于PEG沉淀法检测macro-TSH的证据，以规范其在临床实践中的应用。
根据PRISMA指南，截至2024年8月，我们对PubMed和Scopus数据库进行了全面检索，使用了与macro-TSH和PEG沉淀相关的术语。
我们纳入了23项研究，共4476名受试者，包括10项观察性研究和13项病例系列/报告。所有研究显示偏倚风险较低。这些研究在三级中心进行，纳入了从新生儿到老年受试者。关于该方法的大多数证据是在PEG浓度为12.5%的情况下获得的。macro-TSH病例的PEG可沉淀TSH始终高于75%，平均范围为81%至90%。非macro-TSH病例（对照）的PEG可沉淀TSH百分比范围为44.1%至61.8%。
PEG沉淀法可被视为检测macro-TSH的有用诊断工具。然而，对于临床高度可疑的病例，有必要进行PEG沉淀，同时进行所有可用的辅助检查。PEG可沉淀TSH > 75%可被视为macro-TSH病例的可靠诊断阈值。
