The goals of testing include detecting thyroid dysfunction, diagnosing Graves disease, and monitoring Treatment.
To detect thyroid dysfunction, testing may begin with:
- TSH — typically low in Graves disease
- Total or free T4 — usually elevated
- Total or free T3 — often elevated
The above tests may also be ordered periodically to monitor thyroid function and hormone production.
- Thyroid stimulating immunoglobulin (TSI) — The presence of this antibody is diagnostic for Graves disease.
- Thyroid stimulating hormone receptor antibody (TRAb) — less specific than TSI
- Anti-thyroid peroxidase antibody (anti-TPO) — This autoantibody is found in most people with Graves disease as well as in Hashimoto thyroiditis.
- Radioactive iodine uptake — For this test, a capsule or "cocktail" containing a measured amount of radioactive iodine is swallowed; iodine is a critical component of thyroid hormones. The iodine accumulates in the thyroid; more accumulates when the gland is overactive, as occurs in Graves disease. After a specified amount of time, a probe similar to a Geiger counter is placed over the thyroid and the amount of radioactivity is compared to the amount that was given. For additional details, visit Radiologyinfo.org.