SAT462 TSI Versus TRAb In The Diagnosis Of Grave’s Disease

Abstract

Abstract Disclosure: K. Ibrahim: None. K. Raju: None. M. Morkos: None. Objective: Improvement in the thyroid antibody titers can help in predicting the remission of Graves’ disease. We aimed to assess the level of elevation of the antibody titers, thyroid stimulating immunoglobulin (TSI) and thyroid receptor antibody (TRAb) in patients with Grave’s disease. Research and Design Methods: This is a retrospective cross-sectional study of patients diagnosed with Graves’ disease at an academic outpatient endocrinology clinic from August 2019 to November 2022. TSI and TRAb were measured synchronously during the initial assessment of the patients, titers were compared against the upper limit of normal to assess their level of elevation. TSI was measured using Semi-Quantitative Chemiluminescent Immunoassay and TRAb using Quantitative Electrochemiluminescent Immunoassay. SPSS® (version 28) was used for statistical analysis, descriptive statistics were utilized and paired-sample t-test was used to compare TSI And TRAb ratios. Results: We identified 41 patients who presented for initial assessment of Graves’ disease, 31 (75.6%) were female, 23 (56.1%) Caucasian, and 16 (39.0%) African American. Mean age (± standard deviation) 46.3 ± 14.2 years. Mean TSI 8.3 ± 15.9 IU/L (ref <0.55), TSI ratio of elevation above the upper limit of normal was 11.1 ± 15.3, Mean TRAb 8.9 ± 9.4 (ref ≤1.75), TRAb ratio of elevation above the upper limit of normal was 5.1 ± 5.4. The correlation coefficient for both TSI and TRAb ratios was 0.92 (p <0.001). One patient had a normal TSI but elevated TRAb level and two patients had a normal TRAb level but elevated TSI levels. Conclusion: TSI was more highly elevated above its normal range than TRAb. TSI can be a reasonable initial antibody test for patients with Graves’ disease to establish a baseline. Presentation: Saturday, June 17, 2023