Thyroid Stimulating Hormone Blood Test, from our experts to you.
Dr Sam Rodgers MBBS, MRCGP

Chief Medical Officer meet our doctors

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What is a
Thyroid Stimulating Hormone Blood Test?

Our Thyroid Stimulating Hormone Blood Test is an entry-level test for thyroid function that measures the amount of thyroid-stimulating hormone (TSH) in your blood. A TSH test is often the first test for evaluating thyroid function and symptoms of hyper or hypothyroidism.

What are the symptoms
of a thyroid condition?

Symptoms of an overactive thyroid (hyperthyroidism) include heat intolerance, weight loss, heart palpitations and breathlessness. On the flip side, symptoms of an underactive thyroid (hypothyroidism) include fatigue, weakness, weight gain, slow heart rate, and cold intolerance.

Which hormones does
the thyroid make?

Your thyroid produces hormones that affect almost every cell in your body. Thyroid hormones thyroxine (T4) and triiodothyronine (T3) help regulate the rate your body uses energy. Thyroid-stimulating hormone (TSH) is produced in the pituitary gland and regulates the production of T3 and T4. It is usually measured as a proxy for thyroid hormones T4 and T3. When circulating hormones are low, TSH elevates, and when circulating hormones are high, TSH will be low. Raised levels of TSH can indicate that the thyroid is struggling to produce sufficient quantities of thyroid hormones and is underactive. Low levels can show that the thyroid produces excess levels of thyroid hormones and is overactive.

What's Included?

Thyroid hormones
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TSH Thyroid stimulating hormone (TSH) is produced in the pituitary gland in order to regulate the production of thyroid hormones thyroxine (T4) and triiodothyronine (T3) by the thyroid gland. If thyroid hormones in the blood are low, then more TSH is produced to stimulate the thyroid gland to produce more of them. If thyroid hormone levels are high, then the pituitary produces less TSH to slow the production of thyroid hormones. If TSH is too high or too low, it normally signifies that there is a problem with the thyroid gland which is causing it to under or over produce thyroid hormones. Sometimes a disorder of the pituitary gland can also cause abnormal TSH levels.

How to prepare
for your test?

Special Instructions

Prepare for your Thyroid Stimulating Hormone Blood Test by following these instructions. Please take your sample before 10am. Do not take biotin supplements for two days before this test, discuss this with your doctor if it is prescribed.