Thyroid Tests
Various laboratory blood tests are used to assess thyroid gland function, detect abnormalities, diagnose diseases, and monitor treatment effectiveness.
Main tests for thyroid evaluation:
- Thyroid-stimulating hormone (TSH) — the primary marker of thyroid function, regulated by the pituitary gland and stimulates hormone production by the thyroid.
- Free thyroxine (T4 free, fT4) — the main thyroid hormone reflecting functional activity and involved in metabolism regulation.
- Free triiodothyronine (T3 free, fT3) — the active hormone form influencing energy metabolism, mood, weight, and other bodily processes.
- Antibodies to thyroid peroxidase (Anti-TPO) — indicate autoimmune processes where the immune system attacks thyroid cells.
- Antibodies to thyroglobulin (Anti-TG) — suggest possible autoimmune thyroid diseases.
- Thyroglobulin (TG) — used for monitoring patients after thyroid removal due to cancer and for recurrence control.
- Calcitonin — important for diagnosis and monitoring of medullary thyroid cancer.
Additional tests:
- Antibodies to TSH receptors (Anti-TSHR) — for suspected Graves’ disease (diffuse toxic goiter).
- Total T3 and T4 — less commonly used as free forms are more informative.
When tests are ordered:
- Suspected hypothyroidism or hyperthyroidism (thyroid dysfunction).
- Detection of nodules on ultrasound.
- During pregnancy.
- For monitoring thyroid disease treatment.
- After surgery to remove the thyroid or when tumors are suspected.
Sample material: venous blood.
These tests may be ordered individually or as a panel, depending on the clinical situation and diagnostic goals.