Endocr Pract. 2018 Jun;24(6):512-516. doi: 10.4158/EP-2018-0059. Epub 2018 Apr 6.
Thyrotropin (TSH) receptor antibody (TRAb) testing is considered accurate for the diagnosis of Graves disease (GD) and has been identified rarely in thyrotoxic patients without GD. We describe 4 patients with transient thyrotoxicosis and positive TRAb to highlight this clinical possibility.
Patient demographics, symptoms, laboratory findings, and time to resolution of thyrotoxicosis are summarized. TRAb testing was performed by either a third-generation thyrotropin-binding inhibitory immunoglobulin (TBII) competitive-binding assay or a thyroid-stimulating immunoglobulin (TSI) bioassay from either Mayo Clinic Laboratory or Quest Diagnostics.
Four patients with transient thyrotoxicosis and positive TRAb testing were identified. Of these, three were female, and the median age was 44 years (range, 25 to 49 years). Median symptom duration at evaluation was 6.5 weeks (range, 3 to 12 weeks). No patient had any clinical manifestations unique to GD or exposure to biotin, thyroid hormone, supplements, iodine, or relevant medications. The TSH was <0.1 mIU/L in all patients. Three patients had a positive TSI, which was elevated less than twice the upper limit of the reference range in all cases, and 1 patient had a strongly positive TBII. None of the patients were treated with thionamides or radioactive iodine. Spontaneous resolution occurred in all patients at a median of 5.5 weeks (range, 2 to 14.4 weeks).
These cases demonstrate that TSI or TBII may be present in thyrotoxic patients with transient thyrotoxicosis. For clinically stable patients presenting without pathognomonic evidence of GD, mildly elevated TRAb results may require cautious interpretation, and alterative diagnostic testing or close monitoring should be considered.
cAMP = cyclic adenosine monophosphate; FT4 = free thyroxine; GD = Graves disease; TBII = thyrotropin-binding inhibitory immunoglobulin (also known as TBI); TRAb = thyrotropin receptor antibody; TSH = thyrotropin; TSHR = thyrotropin receptor; TSI = thyroid-stimulating immunoglobulin; TT3 = total triiodothyronine; TT4 = total thyroxine.
促甲状腺素（TSH）受体抗体（TRAb）检测被认为可准确诊断格雷夫斯病（GD），并且在无 GD 的甲状腺毒症患者中很少发现。我们描述了 4 例一过性甲状腺毒症和阳性 TRAb 的患者，以强调这种临床可能性。
总结患者的人口统计学、症状、实验室发现以及甲状腺毒症缓解时间。TRAb 检测是通过第三代促甲状腺素结合抑制免疫球蛋白（TBII）竞争性结合测定法或甲状腺刺激免疫球蛋白（TSI）生物测定法进行的，这些检测法来自梅奥诊所实验室或 Quest 诊断公司。
确定了 4 例具有一过性甲状腺毒症和阳性 TRAb 检测的患者。其中 3 例为女性，中位年龄为 44 岁（范围 25 至 49 岁）。评估时的中位症状持续时间为 6.5 周（范围 3 至 12 周）。没有患者有 GD 特有的任何临床表现或接触过生物素、甲状腺激素、补充剂、碘或相关药物。所有患者的 TSH 均<0.1mIU/L。3 例患者的 TSI 阳性，所有病例的 TSI 均升高不到参考范围上限的 2 倍，1 例患者的 TBII 强阳性。所有患者均未接受硫脲类药物或放射性碘治疗。所有患者的自发缓解中位时间为 5.5 周（范围 2 至 14.4 周）。
这些病例表明，TSI 或 TBII 可能存在于具有一过性甲状腺毒症的甲状腺毒症患者中。对于临床稳定且无 GD 特征性证据的患者，轻度升高的 TRAb 结果可能需要谨慎解释，应考虑替代诊断性检测或密切监测。
cAMP = 环磷酸腺苷；FT4 = 游离甲状腺素；GD = Graves 病；TBII = 促甲状腺素结合抑制免疫球蛋白（也称为 TBI）；TRAb = 促甲状腺素受体抗体；TSH = 促甲状腺素；TSHR = 促甲状腺素受体；TSI = 甲状腺刺激免疫球蛋白；TT3 = 总三碘甲状腺原氨酸；TT4 = 总甲状腺素。
