Diagnostics
Thyroid Function Test
What are thyroid function tests?
Thyroid function tests are a group of blood tests used to evaluate the thyroid gland functioning.
Other names for this test are Thyroid profile, Thyroid panel, T3, T4, TSH test, and TFT.
How does the thyroid gland work?
Who conducts the thyroid function test?
When the doctor suspects imbalances in thyroid hormone levels, they may order comprehensive screening tests such as the T3, T4, or thyroid- stimulating hormone (TSH) test to assess the functioning of the thyroid gland. Generally, fasting is not required before doing this test. An individual can eat and drink normally unless the doctor suggests otherwise.
A laboratory technician will locate a vein in the arm, clean the site, and insert a small needle to draw blood into a vial. The process typically takes a few minutes. The blood sample will be sent to a lab for analysis.
Who should get a thyroid function (TFT) test?
- If there are signs or symptoms suggestive of thyroid dysfunction
- Fatigue
- Weight changes
- Changes in heart rate
- Muscle weakness
- Changes in mood or mental functioning
- Changes in menstrual patterns
- Dry skin and hair
- Sensitivity to cold or heat
- If an individual is taking medicines that can affect thyroid function, such as amiodarone and lithium
- If the lady is pregnant
- If an individual is on thyroid medication such as thyroxine, a thyroid test is recommended to monitor the response to it.
Thyroid Blood Test
What are normal thyroid levels?
- Thyroid-stimulating hormone (TSH): 0.4 to 4.0 mIU/L (milli-international units per liter).
- Free thyroxine (FT4): 0.8 to 1.8 ng/dL (nanograms per deciliter).
- Triiodothyronine (T3): 80 to 200 ng/dL (nanograms per deciliter).
References
- American Thyroid Association. Thyroid Function Tests. Available from: https://www.thyroid.org/thyroid-function-tests/
- Healthline. Thyroid Function Tests. [Internet]. Available from: https://www.healthline.com/health/thyroid-function-tests#results.
- Cleveland Clinic. Thyroid Blood Tests. [Internet]. Available from: https://my.clevelandclinic.org/health/diagnostics/17556-thyroid-blood-tests
- Thyroid Panel Test. Available from: https://www.testing.com/tests/thyroid-panel/
- Pearce EN, Farwell AP, Braverman LE. Thyroiditis. N Engl J Med. 2003;348(26):2646-2655