Thyroglobulin Antibody: Overview, Reference Ranges, High Levels

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The Thyroid is responsible for the production of two essential hormones that play a role in metabolism. The gland is relatively small in size and a shape like a butterfly.

Thyroglobulin is a type of glycoprotein homodimer or a protein to keep things simple. This particular protein is made by the Thyroid gland. Thyroglobulin is involved in the synthesis of Thyroid hormones, including both triiodothyronines, as well as thyroxine1.

Furthermore, the protein also assists with the storage of iodine, as well as thyroid hormones that are in an inactive form.

In patients suspected to have Thyroid-related diseases, a blood test may be performed to determine if there are Thyroglobulin antibodies in the patient’s body.

This type of test can assist in the diagnosis of these conditions, as well as help the physician or specialist understand what treatment protocols will be most appropriate for a particular patient.

What Are Thyroglobulin Antibodies

Thyroglobulin antibodies play a role in autoimmune conditions that cause a patient to develop Thyroid diseases. The term refers to the body developing antibodies that attack the Thyroglobulin proteins that are active within the Thyroid.

When these proteins are attacked by the immune system, then the Thyroid may become damaged. This can, in turn, lead to the development of certain diseases associated with the Thyroid gland – the result of which would be an impairment in the gland’s function.

Thyroglobulin antibodies are sometimes referred to as anti-thyroid antibodies as well.

A review paper2 led by the University of Tuebingen in Germany describes that patients with autoimmune Thyroid diseases have elevated levels of these antibodies in their blood circulatory system.

The same paper also describes that researchers sometimes find an elevation of these antibodies in the body, even when the patient does not present an impairment of their Thyroid function.

The study also describes a potential effect that these Thyroglobulin antibodies may have on the thyroid-stimulating hormone receptors that are located in this particular gland. This may further describe the dysfunction of the Thyroid gland that is often observed in patients with the antibodies present in their blood.

The presence of anti-thyroid hormones may also have an impact on the risk of cancer. In one study3, a connection was found between the level of these antibodies in the patient’s body and the possibility of developing Thyroid-related cancers. The presence of a condition such as Hashimoto’s disease and other autoimmune Thyroid conditions also seem to have a role to play in the risk of cancers affecting this gland.

Furthermore, some studies have found that Thyroglobulin antibodies may have extra-thyroidal effects in the body, which means they may affect parts of the body other than the Thyroid gland itself as well.

How Is A Thyroglobulin Antibody Test Performed?

A Thyroglobulin antibody test is relatively simple and straightforward and does not require any invasive procedures in the patient suspected to have an autoimmune Thyroid disorder.

The test ordered will be referred to as either one of the two:

  • Thyroglobulin antibody test
  • Thyroid antibody test

Only a single blood sample is usually needed to perform this particular test. A needle will be used during the procedure, which will allow the physician or scientist to withdraw blood from the patient’s body. The needle will be inserted into the hand or arm of the patient, directly into a vein.

Once a blood sample has been collected, it will be sent toward a laboratory that specializes in performing blood tests.

Thyroid Antibody Reference Ranges

Patients should be able to understand the results of their tests thoroughly. It is important to note that physicians will usually take a look at various results when they order tests to see if an autoimmune action is causing the patient difficulties with their Thyroid function.

Generally, Thyroglobulin antibodies often referred to as “TgAb” on test results, should read 20 IU/mL or less on the test results to provide a “normal” reading. Anything higher than this means there are too many of these antibodies in the patient’s body. This, in turn, may yield adverse effects and cause Thyroglobulin proteins in the patient’s Thyroid gland to be attacked by their immune system.

Another important antibody test that may also be requested is to test for Thyroid Peroxidase antibodies in the patient’s blood. If there is a presence of these antibodies, then the reading should ideally be 35 IU/mL or less.

When the antibody levels are higher, it may indicate a reaction by the patient’s immune system attacking the Thyroid gland and adversely affecting the gland’s ability to produce Thyroid hormones effectively.

It is important that the patient also notes that even when the antibody tests fall below these references, there may still be problems with their Thyroid if they experience symptoms associated with Hypothyroidism or Hyperthyroidism.

A complete Thyroid test should be conducted to help the physician understand if the patient’s Thyroid is functioning properly. If autoimmune diseases are not an underlying cause for Thyroid-related issues, then another potential cause needs to be identified.

Who Needs To Undergo A Thyroglobulin Antibody Test?

The Thyroglobulin antibody test is usually performed when a physician suspects that a patient may have a Thyroid disorder.

Since the Thyroid gland produces two crucial hormones that have a role to play in metabolism, many symptoms can start to develop when the patient develops a condition that adversely affects this part of the body.

A physician will start by asking the patient about the symptoms that they are experiencing. A physical examination will be conducted. If the physician expects a possibility of issues with the patient’s Thyroid gland, then the neck region will be taken into careful consideration during the physical examination.

Thyroid diseases cannot be diagnosed with a physical examination alone. A series of additional tests will be required. The physician will need to determine if the patient has elevated levels of Thyroid hormones or perhaps a deficiency of these hormones in their bodies.

It is also important for patients to understand the particular symptoms associated with common Thyroid diseases. This can help a patient understand if they might require Thyroid testing, including the possibility of undergoing Thyroglobulin antibody tests.

It should be noted that the Thyroglobulin antibody test is usually conducted in addition to other particular Thyroid-related tests to assist in determining if the changes in Thyroid hormones may be due to an autoimmune condition.

Thyroid Diseases And Related Symptoms

There are two primary types of autoimmune conditions that affect the Thyroid gland. This includes Graves’ disease, which usually leads to Hyperthyroidism. In such a case, the patient will experience an excessive amount of Thyroid hormones in their circulatory blood system4.

When the patient has too many Thyroid hormones in their body, then they can experience the following symptoms:

  • The patient may experience weight loss without putting in any effort to do so
  • The patient may feel irritable and nervous
  • Anxiety may develop
  • An irregular heartbeat may occur
  • A feeling of tiredness and weakness may occur
  • An increase in sweating
  • Reduced tolerance to heat

Hashimoto’s disease is another autoimmune condition that causes problems with the Thyroid gland. This condition tends to contribute to the development of Hypothyroidism. This disease leads to a decrease in the number of thyroxine and triiodothyronine, both being important Thyroid hormones5. The result would be a slower metabolism.

Symptoms that a patient may experience when they have Hypothyroidism, including in cases where the underlying cause may be Hashimoto’s disease, can consist of the following:

Female patients may also experience issues with their menstruation cycles if they have Hypothyroidism.

Other Tests That May Also Be Requested

While a Thyroglobulin antibody test is certainly a very useful option to assist in determining if a patient may have an autoimmune condition attacking their Thyroid gland, there are other tests that may also be ordered alongside this one.

These tests can further assist in the diagnosis of the patient and ensure the physician is able to determine the severity of the patient’s condition. Furthermore, these tests can also be utilized to help the physician in providing the patient with the appropriate medication and doses to treat the particular condition they are diagnosed with.

Additional tests may assist in providing a count or concentration level on the following substances and hormones in the patient’s blood sample:

  • Triiodothyronine levels also called T3 hormones
  • Thyroxine levels also called T4 hormones
  • Thyroid-stimulating hormone levels, also known as TSH

A crucial reason why TSH levels also need to be tested is that this hormone stimulates the Thyroid gland to produce the hormones Triiodothyronine and Thyroxine. When levels of this hormone are affected, it may have implications for the Thyroid gland as well.

Are There Any Risks Associated With A Thyroglobulin Antibody Test?

A Thyroglobulin antibody test is generally considered very safe. The patient will simply be asked to sit still while a needle is used to withdraw a vial of blood from their arm. In some cases, a vein may rather be used in the patient’s hand to extract blood.

Some bruising may occur in the area where the blood is extracted, but this will resolve in just a few days. There are cases where a patient may experience slight pain in the region, but this type of side-effect will also subside quickly. Patients should be aware that a minimal risk of infection associated with this procedure. This is, however, a very rare complication.

What Patients Should Know About A Thyroglobulin Antibody Test

Patients who have been requested to undergo a Thyroglobulin antibody test should understand the protocols involved in the test, and ensure they prepare themselves. While the test is simple and does not pose significant risks to the patient, there are certain factors that may influence the results of the blood tests.

The patient should provide their physician with details of an existing medication that they might be taking. This would include both prescription medications and non-prescription medications. The use of multivitamins and herbal supplements should also be noted to the patient’s physician.

This will help the physician understand if any factors may have an impact on the patient’s blood tests. The patient may be advised to stop using some types of medications or supplements prior to undergoing a Thyroglobulin antibody test.


Thyroid disorders are exceptionally common in the modern day. Different conditions have been identified to have adverse effects on Thyroid function, either causing Thyroid hormone levels to increase or to decrease.

This may yield complications for metabolic functions, as well as other areas of the body that depend on Thyroid hormones. A Thyroglobulin antibody test can assist in understanding if the body has made antibodies that attack the protein involved in the production of these hormones and can be a useful diagnostics tool in patients suspected to have developed a Thyroid disease.


1 T Thyroglobulin [Homo sapiens (human)]. NCBI: Gene Database. 5 Mar 2019.

2 E. Frohlich, R. Wahl. Thyroid Autoimmunity: Role of Anti-thyroid Antibodies in Thyroid and Extra-Thyroidal Diseases. Frontiers in Immunology. 9 May 2017.

3 C.A. Spencer. Clinical review: Clinical utility of thyroglobulin antibody (TgAb) measurements for patients with differentiated thyroid cancers (DTC). The Journal of Clinical Endocrinology and Metabolism. 14 Sep 2011.

4 S.D. Leo, S.Y. Lee, L.E. Braverman. Hyperthyroidism. HHS Public Access. 27 Sep 2016.

5 N. Patil, I. Jialal. Hypothyroidism. StatPearls. 7 Jan 2019.

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