Thyroid-stimulating immunoglobulins as a reliable predictive blood test for thyroid eye disease

Thyroid stimulating hormone, T3, T4, and thyroid auto-antibodies are essential in diagnosis of immune thyroiditis, Graves' and Hashimoto's. These, however, may not correlate with thyroid eye disease or TED. In recent years, a new blood test for thyroid stimulating immunoglobulins (TSI) is in use. However, there is no sufficient clinical evidence of their role in TED. The purpose of the current study is to evaluate the correlation between TSI and TED activity and to examine if TSI is a predictor for the severity of the disease.

A retrospective analysis of electronic medical records of all patients who attended TED clinic at Sheba Medical Center, Israel between 2017 and 2022 and had at least one TSI sample was performed. Data included demographics, comprehensive ophthalmic examination, clinical activity scores (CASs), laboratory tests, and quality of life assessment by the Graves' Orbitopathy QOL questionnaire.

60 patients with 43 females (72%) were included. TSI at presentation correlated with eyelid retraction, IOP (Pearson correlation, 0.369, P< =0.01), and CAS (Pearson correlation, 0.392, P = 0.029). TSI values >500% were found to be significantly correlated with the use of medical treatment including high-dose steroids (P = 0.05), steroid treatment according to the European Group on Graves' Orbitopathy protocol (P = 0.02), and radioactive iodine (P = 0.03). Moreover, it was also significantly correlated with surgical procedures including decompression (P = 0.016) and strabismus surgeries (P = 0.024).

TSI is correlated with more severe clinical presentation and higher likelihood of medical or surgical treatment. Therefore, TSI can be considered as a predictor factor for the disease. Routing testing for TSI may be warranted for all TED patients.