What is an antithyroglobulin antibody test?
Antithyroglobulin antibody test is done to measure the levels of antithyroglobulin antibodies in the blood. The thyroid gland is a gland situated anteriorly in the neck. It is responsible for making the thyroid hormones – thyroxine and triiodothyronine. In the path of formation of thyroid hormones, the protein thyroglobulin is first made and this is later used for the synthesis of the active form of the thyroid hormone. Thyroid hormones regulate the metabolic processes of the body. When an autoimmune disease is present in the thyroid gland, alterations exist in the production of the protein thyroglobulin. The immune system ends up producing antithyroglobulin antibodies because the presence of this autoimmune condition means that the immune system wrongfully attacks the thyroid gland. An autoimmune condition occurs when the healthy, normal cells of the body are being fought by antibodies made by the immune system. The antithyroglobulin antibody test is usually requested by a doctor to ascertain the levels of the antithyroglobulin antibodies in circulation as an elevated value may suggest an autoimmune condition.
Indications for an antithyroglobulin antibody test
When an individual presents to a physician with signs and symptoms suggestive of a thyroid disorder, the doctor usually would request for the antithyroglobulin antibody test. The presenting symptoms and signs include:
- Excessive tiredness
- Weight gain despite a poor appetite
- Dry skin
In addition, a neck swelling when clinically examined and found to be a goiter may also necessitate this test. A goiter is a swelling of the thyroid gland situated in the anterior neck. When an autoimmune condition of the thyroid gland such as Hashimoto thyroiditis and Grave’s disease are suspected, the test should be ordered. This antithyroglobulin antibody test helps to check for abnormal functioning of the thyroid gland.
Preparation for the test
Like most tests, a blood sample is needed. This sample may be drawn by a doctor, phlebotomist, nurse or any other trained health care worker. Prior to this test, speak to your doctor about any drugs you are taking, whether they are prescription-only medications or over-the-counter drugs. Tell them also about any dietary supplement you are on. Do not stop taking any medication by yourself, do that only if the doctor says so. The doctor will tell you what to do and what not to do. He may ask you to temporarily fast for the test-for few hours maybe. For some likely drugs that may affect the test results, your doctor would ask you to withhold intake. Example of such drug that may interfere is the blood thinner warfarin. Multivitamins can also interfere.
Procedure for the antithyroglobulin antibody test
When the blood is drawn either in the hospital or laboratory, the sample is then sent for analysis. For sample collection, an elastic band is tied at the upper arm over the site of collection, the vein is located and site disinfected, needle bearing a tube is inserted and the blood is collected into the tube.
Risks associated with the antithyroglobulin antibody test
Like most other blood tests, the risks associated with this test are minimal. Slight discomfort or pain may be felt when the blood is drawn, bruising may even occur. Multiple needle sticks when blood sample collection proves difficult. Other risks that may be incurred include:
- Dizziness due to blood loss
- Blood accumulation under skin called hematoma
- Infection at the puncture site- is a delayed reaction
- Venous inflammation devoid of clot formation called phlebitis
To perform any test or as a general principle, the usefulness has to be more than the risk involved in the process.
Interpretation of test results
For the test to be taken as normal, the result should be negative meaning that antithyroglobulin antibodies were not detected in the blood sample that was gotten. Once any quantity of antithyroglobulin antibodies has been detected, it may be a pointer to any of the following conditions:
- Diabetes mellitus, type 1
- Pernicious anemia which means a decline in the quantity of red blood cells due to a vitamin B-12 deficiency
- Connective tissue disorders such as Rheumatoid arthritis and Scleroderma
- Cancer of the thyroid
An elevated antithyroglobulin antibody level may be a pointer to an autoimmune condition of the thyroid gland example Grave’s disease or Hashimoto thyroiditis.
For some other people who may have the antithyroglobulin antibodies (test positive to antithyroglobulin antibodies) but in the absence of any particular complication, they just need to be effectively monitored in case any disease condition comes forth.
The doctor will extensively explain the results of the test. The next steps to be taken will depend on the diagnosis made from the results. Further tests may even be requested for if needed. Always remember to ask the doctor questions on the result to ensure that all doubts are cleared.