Thyroid Function medical test
Learn about Thyroid Function Test medical tests, including what the tests are used for, why a doctor may order a test, how a test will feel, and what the results may mean.
What is Thyroid Function Test?
Thyroid function tests are a series of blood tests used to measure how well your thyroid gland is working. Available tests include the T3, T3RU, T4, and TSH. Blood tests for thyroid function are an important part of diagnosing and treating thyroid disorders.
What the Thyroid Function Test test used for?
Thyroid function tests can also be done to:
- Monitor treatment with thyroid replacement medicine for people who have hypothyroidism.
- Check thyroid gland function in people who are being treated for hyperthyroidism.
- Screen new born babies for inherited problems with the thyroid gland.
How is the procedure performed?
A thyroid function test is a simple blood test. The blood sample is then sent to the laboratory for analysis and the results are sent back to the doctor who asked for the tests. The results usually take 1-3 days to come back.
What will be the results interprets?
The interpretation of the test results can vary based on the individual and comparative values. The one test that arguably provides the most insight is the TSH. When used in combination with free T3 and free T4, the TSH can also suggest the cause of an abnormality.
| TSH Test | |
|---|---|
| Result | Interpretation |
| 4.7 - 10 mU/L | Subclinical hypothyroidism |
| Over 10 mU/L | Overt (symptomatic) hypothyroidism |
| 0.1 - 0.5 mU/L | Subclinical hyperthyroidism |
| Below 0.1 mU/L | Overt hyperthyroidism |
| 0.4 - 4.0 mIU/L | Normal |
| T3 Test | |
| 100–200 ng/dL | Normal |
| Abnormally high levels | Indicate a condition called Grave’s disease. This is an autoimmune disorder associated with hyperthyroidism. |
Other related tests for Thyroid Function Tests: Thyroid Profile (Free T4), Thyroid Stimulating Hormone (TSH)