Thyroid Function with Antibodies 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 Function with Antibodies Blood Test?

Our Thyroid Function with Antibodies Blood Test offers an affordable insight into what could be causing your thyroid-related symptoms - and many people begin their investigation into a thyroid condition with this test. This test includes thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3). By measuring the amount of thyroid hormone that is free or unbound to carrier proteins in the blood, you can get a better picture of how much thyroid hormone is available to your cells. Additionally, this test also includes tests for thyroglobulin and thyroid peroxidase antibodies.


What causes
a thyroid condition?

Many thyroid-related conditions are caused by autoimmune diseases. Your risk for this is raised if you or a family member has a history of autoimmune disease. Our test looks for specific thyroid antibodies, which can indicate that your thyroid is under attack by your immune system.


What autoimmune diseases
affect the thyroid?

The two main autoimmune conditions that affect the thyroid are Hashimoto's thyroiditis (which causes hypothyroidism) and Graves' disease (which causes hyperthyroidism). While there isn’t a cure for either of these, they can be managed with the right treatment plan – so getting tested is important. Your doctor will take your symptoms into account alongside doing some thyroid blood tests to give you a diagnosis of a thyroid disorder.


What's included?

Autoimmunity
Thyroid hormones
Select profile for more information

Thyroglobulin antibodies This test looks for antibodies to thyroglobulin, a protein which is specific to the thyroid gland. Under normal circumstances it does not enter the bloodstream, but if your thyroid is inflamed or under attack from the body's own immune system, then thyroglobulin can be secreted and antibodies detected. Most cases of thyroid disease are caused by an autoimmune condition where the thyroid gland is attacked by the body's own immune system. This can cause the thyroid gland to produce more thyroid hormone (as in the case of Graves' disease) or to produce less as the cells in the thyroid gland are gradually destroyed (as in the case of Hashimoto's thyroiditis).
Thyroid peroxidase antibodies Thyroid peroxidase is an enzyme which is produced in the thyroid gland and is important for converting T4 to the biologically active T3. This test looks for antibodies to thyroid peroxidase which indicates that the body's immune system is attacking the thyroid gland and impairing its function.
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.
Free T3 Triiodothyronine (T3) is the more active of the two thyroid hormones produced by the thyroid gland. Most T3 is bound to protein in the blood. Free T3 measures the level of T3 that is free, or unbound to protein, and is available to regulate metabolism.
Free thyroxine Thyroxine (T4) is one of two hormones produced by the thyroid gland. It works to speed up the rate of your metabolism. Most T4 is bound to carrier proteins in the blood - it is only the free, or unbound, T4 that is active in the body, which is measured in this test. Free T4 is the less active of the two main thyroid hormones. To have an impact on your cells it needs to convert to the more active T3 when your body needs it.

How to prepare
for your test

Special instructions

Prepare for your Thyroid Function with Antibodies Blood Test by following these instructions. Please take your sample before 10am. You should take this test before you take any medication or vitamin/mineral supplements. Do not take biotin supplements for two days before this test, discuss this with your doctor if it is prescribed.


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