From the Guidelines
Graves' disease is diagnosed by a blood test measuring TSH receptor antibodies.
Diagnostic Approach
- The diagnosis of Graves' disease involves laboratory tests, including the measurement of TSH receptor antibodies 1.
- A low TSH level can indicate thyrotoxicosis, but further evaluation is necessary to establish the etiology, which may include Graves' disease, toxic adenoma, or toxic multinodular goiter 1.
- In cases where the diagnosis is ambiguous, imaging with an iodine uptake and scan can help confirm the cause of thyrotoxicosis 1.
- The measurement of TSH receptor antibodies is a key diagnostic test for Graves' disease, as it can distinguish between Graves' disease and other causes of thyrotoxicosis 1.
From the Research
Blood Tests for Diagnosing Graves' Disease
The following blood tests are used to diagnose Graves' disease:
- Thyroid-stimulating hormone (TSH) level test: This test measures the level of TSH in the blood, which can be suppressed in the presence of thyroid-stimulating immunoglobulin (TSI) 2
- Thyroid-stimulating immunoglobulin (TSI) test: This test measures the level of TSI in the blood, which is a relatively new method for assessing TSH-receptor antibodies function 3
- TSH-receptor antibodies (TRAb) test: This test measures the level of TRAb in the blood, which is considered the gold standard diagnostic test for the autoimmunity of Graves' disease 4, 5
- Free thyroxine (T4) and triiodothyronine (T3) level tests: These tests measure the levels of T4 and T3 in the blood, which can be elevated in patients with Graves' disease 2, 3
Comparison of Blood Tests
The TSI test and TRAb test are both used to diagnose Graves' disease, but they measure different aspects of the disease:
- The TSI test measures the functional activity of TSH-receptor antibodies, while the TRAb test measures the presence of these antibodies 3
- The TSI test is considered to be more reflective of the circulating TSI concentration than thyroid gland function, and may be as reliable a predictor of remission as TSI 2
- The TRAb test is considered the gold standard diagnostic test for the autoimmunity of Graves' disease, but the TSI test may also be important in the clinical diagnosis and prognosis of the disease 3, 4, 5