The test is carried out to:
TSH levels help in confirming the diagnosis of hypothyroidism as well as hyperthyroidism and in assessing their severity. TSH is done singularly as a basic screening test for thyroid function. TSH test, along with other tests of the thyroid panel / thyroid profile, helps in accurate diagnosis of underlying thyroid or pituitary disease.
This test is performed when a person has:
The test result is normal if TSH levels are 0.5-5.0 mU/L.
It means either of the following:
If TSH levels are above 10 mU/L (high); and corresponding free T4 levels are below 5.0 pmol/L (low), it indicates either of the following:
If TSH levels are below 0.5 mU/L (low); and corresponding free T4 levels are above 25.0 pmol/L (high), it indicates either of the following:
If TSH levels are between 5 - 10 mU/L and Free T4 levels are 9.0-25.0 pmol/L; it means subclinical hypothyroidism. i.e. no symptoms
If TSH levels are below 0.5 mU/L (low) and Free T4 levels are below 9 pmol/L (low); it means either of the following:
If Free T3 levels are above 8 pmol/L (high), it means hyperthyroidism. If Free T3 levels are very high, it means severe form of hyperthyroidism.
Other tests that can be done after TSH is tested include: