In order to diagnose Basedow’s disease, we begin by assessing a patient’s symptoms. We perform blood tests and, in some cases, a radioactive iodine uptake test. In addition, ultrasonography is performed to detect possible complications. Since a burden may be placed on the heart due to high thyroid hormone levels, chest radiography or electrocardiography may also be used.
- (1) Blood test
- A blood test is carried out in order to confirm abnormalities, including increased thyroid hormone (FT3 and FT4) levels, low thyroid-stimulating hormone (TSH) levels, and high anti-TSH receptor antibody (TRAb) levels.
- (2) Radioactive iodine uptake test
- If a blood test reveals normal or slightly elevated TRAb levels, a definitive diagnosis needs to be made using a radioactive iodine uptake test with radioactive iodine and technetium. If thyroid hormone production is excessive, as in the case of Basedow’s disease, the incorporation rate of these isotopes into the thyroid will be high.
- (3) Ultrasonography
- This examination is performed to assess the size of the thyroid and detect the presence of nodules.
- (4) Electrocardiography and chest radiography
- These examinations can detect arrhythmia and heart failure, which may occur in a state of hyperthyroidism.
Precautions for a radioactive iodine uptake test
- In an examination using radioactive iodine, patients need to limit intake of food containing high levels of iodine for seven days before the examination.
- Since a radioactive substance is used, this examination is not suitable for pregnant women. Women who are breastfeeding undergo the examination using an isotope with a short half-life* (123I). After the examination, they will need to temporarily refrain from breastfeeding for three days (including the day of the test).A detailed explanation is given when a radioactive iodine uptake test is performed.
*Half-life: the time required for a 50% reduction in the radioactive substance in the body.