Ibrahim, N., Hamam, A. (2020). Diagnostic Value of Estimating the Ratio of Serum Free Triiodothyronine to Free Thyroxine in Differenti-ating Graves' Disease from Thyroiditis. Suez Canal University Medical Journal, 23(2), 135-142. doi: 10.21608/scumj.2020.124698
Nesma A Ibrahim; Ahmed M Hamam. "Diagnostic Value of Estimating the Ratio of Serum Free Triiodothyronine to Free Thyroxine in Differenti-ating Graves' Disease from Thyroiditis". Suez Canal University Medical Journal, 23, 2, 2020, 135-142. doi: 10.21608/scumj.2020.124698
Ibrahim, N., Hamam, A. (2020). 'Diagnostic Value of Estimating the Ratio of Serum Free Triiodothyronine to Free Thyroxine in Differenti-ating Graves' Disease from Thyroiditis', Suez Canal University Medical Journal, 23(2), pp. 135-142. doi: 10.21608/scumj.2020.124698
Ibrahim, N., Hamam, A. Diagnostic Value of Estimating the Ratio of Serum Free Triiodothyronine to Free Thyroxine in Differenti-ating Graves' Disease from Thyroiditis. Suez Canal University Medical Journal, 2020; 23(2): 135-142. doi: 10.21608/scumj.2020.124698
Diagnostic Value of Estimating the Ratio of Serum Free Triiodothyronine to Free Thyroxine in Differenti-ating Graves' Disease from Thyroiditis
1Department of Internal Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt,
2Department of Internal Medicine, Armed Forces College of Medicine (AFCM), Cairo, Egypt.
Abstract
Background: As the treatment approaches of Graves’ disease (GD) and thyroiditis are different, the differential diagnosis is essential. Aim: To assess the diagnostic value of free triiodothyronine (FT3) to free thyroxine (FT4) ratio for differentiation between GD and destructive thyroiditis. Subjects and Methods: The present study was conducted on 100 newly diagnosed thyrotoxicosis patients; 61 with thyroiditis (group 1) and 39 with GD (group 2) and 20 healthy, age-matched subjects representing a control group (Group 3). All participants underwent medical history taking and clinical examination, serum levels of thyroid-stimulating hormone (TSH), FT3, and FT4 were measured, Technetium 99m thyroid Scan was done to all recruited patients. Results: The present results recorded significant increases in FT3, FT4, and decreases in TSH levels in Graves’ disease group than in the thyroiditis group. There was a statistically significant difference between the study groups regarding FT3/FT4 ratio, which was lower in thyroiditis group than in Graves’ disease group (0.21± 0.03 in group 1 vs 0.35±0.18 in group 2, p-value <0.01), while there was no significant difference between thyroiditis group and the control group. The FT3/FT4 ratio showed a predictive value, with an area under the ROC curve (AUC) of 0.936 (95%CI, 0.876-0.995) for Graves' disease vs. thyroiditis (P < 0.001). Based on the cutoff value of this ratio of more than 0.269 offered a sensitivity of 89.7% and specificity of 91.8%. Conclusion: The results of the present study demonstrated that free thyroid hormones and the FT3/FT4 ratio are useful to differentiate Graves’ disease from destructive thyroiditis.