Definition

An antithyroglobulin or antithyroglobulin antibody test is a test to identify the presence of antibodies to thyroglobulin. Thyroglobulin is a protein made by the thyroid gland. The thyroid gland is located at the front of the neck, a small, butterfly-shaped gland.

The thyroid gland releases hormones that regulate the body's metabolism and produces several proteins including thyroglobulin. Thyroglobulin helps the thyroid gland to produce the hormones triiodothyronine (T3) and thyroxine (T4). These hormones have a role in controlling the metabolic processes, which is the process of the body converting food or drink consumed into energy.

The immune system forms antibodies to protect the body from various pathogens such as viruses, bacteria, and other microorganisms. However, in autoimmune conditions, the antibodies attack healthy cells. When the immune system attacks the thyroid, it usually targets thyroglobulin. This causes it to produce antithyroglobulin antibodies.

Indications

Your doctor will suggest this test if you have symptoms related to thyroid problems, such as:

• Fatigue
• Trouble sleeping
• Muscle weakness or tremors
• Unexplained weight loss
• Constipation
• Dry or flaky skin

In addition, this test can also be used to:

• Detect thyroiditis conditions
• Diagnose thyroid disease caused by autoimmune conditions
• Monitor thyroid cancer therapy

Contraindication

There are no contraindications or conditions that prevent a person from having this test done.

Preparations Prior to Test 

The antithyroglobulin test requires no special preparation except fasting. You will be asked to fast for a few hours before the test is performed.

You are advised to consult your doctor before the test, as there are certain conditions or the use of certain medications such as blood thinners or vitamin supplements that may interfere with laboratory results. These things can affect the results of the test so that it does not reflect your true condition.

Test Procedures

The antithyroglobulin test generally uses a blood serum sample of 0.25 - 0.5 ml. This blood serum sample is taken from a vein and will be collected into a special tube. Laboratory staff will wear special gloves and PPE (Personal Protective Equipment) when taking the test sample.

Before taking the blood, the staff will put on an elastic band and clean the needle stick area with antiseptic swabs. Usually the officer takes blood in the elbow crease area. After the blood is drawn and put into a special tube, the officer will remove the elastic band, apply pressure and clean the needle stick area with antiseptic swabs.

This test procedure only lasts for a few minutes. The blood sample that has been obtained will be examined using special equipment in the laboratory, and the results can be known within a few hours.

Normal And Abnormal Values

Antithyroglobulin test results may vary depending on age, gender, medical history, and others. In general, the following are normal and abnormal values for antithyroglobulin test results.

However, each laboratory has a benchmark range that varies slightly from one laboratory to another according to the guidelines it follows and the machines it uses.

Results and Suggestions (Follow-up Tests)

Normal

If your antithyroglobulin test results show normal levels, it is likely that you have a healthy lifestyle and there are no abnormalities associated with thyroid disease in the absence of specific symptoms and clinical signs.

You are advised to maintain your current healthy lifestyle so as to prevent thyroid disease which is characterized by the presence of antibodies to thyroglobulin.

Abnormal

If the antithyroglobulin test shows an abnormal or positive result, you should consult your doctor. A positive result on the antithyroglobulin test means that antibodies are present in the blood and may indicate the following conditions:

• Hypothyroidism
• Hyperthyroidism
• Goiter disease
• Graves' disease
• Thyroiditis
• Thyroid cancer
• Autoimmune diseases such as lupus and type 1 diabetes

Although your test results show a positive value, it is not recommended that you make a medical diagnosis on your own so it is necessary to see a doctor for a consultation and physical examination if there are certain symptoms and signs.

Consult To The Right Doctor

The results of the antithyroglobulin test in adults can be consulted with a general practitioner, for further examination or to start therapy for an appropriate diagnosis. You can also consult a specialist in metabolic and endocrine consultant internal medicine to discuss your thyroglobulin problem further. In pediatric patients, test results other than normal should be consulted with a pediatrician.