Evaluation of the Prevalence and Laboratory Test Results of Overt Thyrotoxicosis Cases

Background The frequency of thyrotoxicosis may vary between countries and some laboratory test results may be used in etiology research. This study aimed to evaluate the prevalence of thyrotoxicosis diagnoses and laboratory test results. Methods 3246 patients with overt thyrotoxicosis were included in this study. Laboratory test results, epicrisis, thyroid ultrasonography, thyroid scintigraphy, and radioactive iodine uptake test reports of the patients were examined in the study. Results Thyrotoxicosis was found due to levothyroxine overdose in 58.1% of the patients. When this group was excluded, 36.1% of the patients were diagnosed with toxic multinodular goiter most frequently. TRab levels were 8.5 times higher in Graves' disease than in other diagnostic groups. Anti-TPO levels were found to be the highest in the Graves' disease and Hashitoxicosis groups compared to other diagnostic groups (p<0.001). Anti-Tg levels were found to be highest in Graves' disease, Postpartum thyroiditis, and Hashitoxicosis patients (p<0.001). The free triiodothyronine / free thyroxine ratio was significantly higher, a cut-off value of >2.94 provided a sensitivity of 66% and specificity of 64% in diagnosing Graves' disease. Conclusion The causes of thyrotoxicosis show some differences between countries. Patients using levothyroxine should be informed about drug use and dose titration. The free triiodothyronine / free thyroxine ratio can be used in addition to other tests during diagnosis.