About this test
TSH is made by the pituitary gland and tells the thyroid gland how much hormone to produce. A raised TSH commonly suggests an underactive thyroid, and a low TSH can suggest an overactive thyroid. It is usually the first test for thyroid problems.
Why it is done
- To screen for or diagnose thyroid disorders.
- To check symptoms such as tiredness, weight change, hair loss or palpitations.
- To monitor thyroid treatment.
- During pregnancy or while planning pregnancy, when advised.
Preparation
Fasting is not usually required. If you take thyroid medicine, ask your doctor whether to take it before or after the sample.
This information is general and is not medical advice. Please speak to your doctor about your results and treatment.