Why is it important to have a TSH test regularly after I’ve been diagnosed?

A health care practitioner administering an injection to a patient

If you’ve been diagnosed with hypothyroidism and you are being treated, you should have a TSH blood test done after 4 to 8 weeks of treatment. If you’ve changed your dose of hypothyroidism medication, your TSH levels should be checked after 4 to 8 weeks.

Once your TSH levels are stabilized, a TSH test should be done after six months and then at least every year or more often if required by your doctor. Things like your health, weight and age can affect the dose of your medication. Because levothyroxine dosing needs to be precise, annual TSH tests are necessary to avoid the consequences of over- or under-treatment.