What is the thyroglobulin-antibodies test?
The thyroglobulin antibodies test determines the blood levels of antibodies against thyroglobulin. Thyroglobulin is a large glycoprotein molecule produced by the protein-secreting cells of the thyroid gland.
The thyroid gland is a small endocrine gland, present at the base of the neck in front of the trachea, responsible for producing two major hormones, T4 (thyroxine or tetraiodothyronine) and T3 (triiodothyronine). Both of these hormones have a great impact on our bodies' metabolic rate and growth.
T3 and T4 are synthesized when thyroglobulin combines with iodine. The thyroid hormones are formed and stored within the thyroglobulin molecule. When the hormones have to be released in the circulating blood, they are detached from the thyroglobulin and then released in free forms.
Thyroglobulin antibodies test is done to ensure that our immune system is not making significant amounts of antibodies against thyroglobulin. Usually, antibodies are made by our immune system against foreign bodies, bacteria, or toxins to fight them and not let them affect our body.
What is this test used for?
Thyroglobulin-antibodies test usually detects an autoimmune disorder in the thyroid gland. Suppose our immune system is disturbed or malfunctioned and produces antibodies against the thyroid gland. In that case, the thyroglobulin-antibodies test result will have their levels high, which will destroy our thyroid gland. The quantities of the hormones produced by the thyroid gland will be changed effectively, causing abnormalities in the body's metabolism and other functions of the hormones.
Why and when do you need a thyroglobulin-antibodies test?
Your doctor may suspect an autoimmune disorder and may order a thyroglobulin-antibodies test, if:
- You are having symptoms of thyroid dysfunction, such as;
- Weight gain
- Change in heart rate
- Dry skin
- Hair loss
2. It can also be considered if you have got abnormal test results of the T3 and T4 levels.
3. You will be suspected of an autoimmune disorder if you have developed goiter (a condition in which your thyroid gland is greatly enlarged).
4. Your doctor can also order a thyroglobulin-antibodies test if you have thyroiditis (inflammation of the thyroid gland).
5. If you have been treated for thyroid cancer recently, your doctor may order this test for monitoring purposes.
What kind of sample is required?
For the testing of thyroglobulin antibodies, a blood sample is taken. Before drawing the blood, an elastic band is tied to your arm to increase the amount of blood in the veins, so it becomes easier to find a vein. After choosing an appropriate vein, blood will be drawn out by inserting a small needle; blood will be collected and sent to the laboratory for examination.
Do you need to prepare for the test?
If required, your doctor may advise you not to eat or drink the night before if you have the test in the morning. Your doctor may also suggest stopping taking certain medications if they alter blood levels of thyroglobulin antibodies. You are not supposed to stop any medicines without your doctor's consent.
Are there any risks to this test?
Any test involving a needle has slight risks like bleeding, soreness, or bruising at the puncture site. You may feel a little uncomfortable while the needle goes in. Besides this, you should contact your doctor if you experience any other issues like:
- Blood accumulation under the skin (hematoma)
- Lightheadedness or dizziness
- Excess bleeding
What does the test result mean?
Usually, a thyroglobulin-antibodies test is considered normal if the levels of antibodies against thyroglobulin are below 20 IU/ml. This range can vary according to the laboratory's measurements. Normal results are also known as the negative thyroglobulin-antibodies test. Thyroglobulin-antibodies levels may change when you have underlying issues with your thyroid gland. Some of the major contributors to altered levels of the thyroglobulin-antibodies and their causes are mentioned below:
1. Autoimmune diseases
When our immune system starts attacking our own body's cells, autoimmune diseases are developed. The thyroid conditions which elevate the thyroglobulin-antibodies level are:
- Hashimoto's disease
This is the most common autoimmune disease of the thyroid. In Hashimoto's disease, autoantibodies destroy the thyroid gland rather than stimulate it.
These patients are first diagnosed with inflammation of the thyroid gland, also known as thyroiditis, which causes deterioration and eventually fibrosis of the gland. Due to Hashimoto's disease, the patient suffers from low or diminished thyroid hormone levels and resultant hypothyroidism.
- Graves' disease
Another autoimmune disease of the thyroid gland eventually causes hyperthyroidism. In graves' disease, autoantibodies have a prolonged stimulating effect on the thyroid gland. This results in high levels of hormone secretion from the thyroid gland.
2. PCOS (polycystic ovarian syndrome)
PCOS is a hormonal disease that usually involves irregular or absent menstrual cycles and issues in pregnancy for females. This condition is due to excess male hormones in the female system but can also occur due to autoimmune thyroid disease. 27% of females suffering from PCOS have their thyroglobulin-antibodies tested positive.
3. High iodine intake
High iodine doses are related to an increment in the thyroglobulin-antibodies, and reduced levels of iodine are seen to reduce the levels of thyroglobulin-antibodies.
- Thyroglobulin test.
- TSH (thyroid-stimulating hormone) levels.
- T4 levels.
- T3 levels.
Frequently ordered together