If an autoimmune disease that affects the thyroid is suspected by a medical provider, then the thyroglobulin blood test is one common method of helping to develop a specific diagnosis. It can be used to help distinguish autoimmune disorders from other issues that may be similar, but related instead to thyroid dysfunction. This test measures the TGAb antibody, which is the storage form of the hormones that the thyroid produces.
When Will This Blood Test Be Ordered?
Many people will live with the signs and symptoms of an autoimmune disorder for some time because many of them can be self-managed fairly easily. In the case of targeted hormone storage antibodies, the symptoms of a thyroid problem depend on if it is over-functioning or under-functioning. Weight gain, fatigue, and dry skin are common for an under-functioning thyroid, while an over-functioning one may create anxiety, tremors, and a rapid heart rate.
The thyroglobulin blood test is also ordered to make sure there aren’t antibodies present that could interfere with other blood tests that have been ordered. This is usually after a thyroid cancer has been detected, but it is also known to occur with Hashimoto’s disease.
Some women who are pregnant or expecting to become pregnant may also have this blood test ordered to eliminate the threat of an autoimmune disease.
What Do My Test Results Mean?
A negative thyroglobulin blood test indicates that there are no detectable antibodies that are attacking the hormone storage centers of the thyroid. This may be an indication that another cause is creating the bothersome signs and symptoms. A small number of people, however, do not develop the antibodies that are detected by this test even when the autoimmune disorder is present, so a negative result is not always a 100% guarantee.
A positive result may indicate a number of medical issues that could require further testing. Thyroid antibodies are common in cancers and autoimmune disorders, but they can also be present in individuals who have undiagnosed Type 1 diabetes or rheumatoid arthritis. Certain forms of anemia and autoimmune vascular diseases are also known to provide positive test results.
Some people may also have a false positive test result. This happens more often in women who are in the 65+ age demographic. The risks of a false positive occurring increase with age. When no thyroid dysfunction can be detected, the positive result is typically treated as an increased risk for future disease development even though most people may never experience such a problem.
Here’s What You Need to Know
The thyroglobulin blood test is fairly specific and sensitive, but it isn’t a 100% guarantee. Because there are different reference points used by individual laboratories in thyroid testing, it is usually best to have this blood test and any others that are thyroid-related to be done in the same place. This provides better monitoring of the health condition because the same methodologies are being used to create results.
Testing for antibodies is not part of the standard process of thyroid testing. It will usually be ordered by a medical provider only when there seems to be an enlarged thyroid or there are symptoms that indicate problems with the storage mechanisms of the thyroid hormones. If there are abnormal test results on the more common blood tests, such as the T3, T4, or TSH, then the thyroglobulin blood test may be ordered as a follow-up to determine if there are specific issues which need to be addressed.
This blood test needs specific equipment for it to be completed. It is not unusual for it to take 5-7 business days to receive results because not every laboratory is equipped to conduct this test. This is especially true for individuals who live in rural areas.
If a thyroid needs to be removed, this blood test is ordered prior to and after the procedure to make sure the cancerous tissues have been removed. It will also be ordered on a regular basis to make sure any thyroid cancer has not returned. About 20% of people who are diagnosed with thyroid cancer will develop antibodies that are detectable by this test.
The thyroglobulin blood test results explained here will help to finalize a diagnosis. It is normal to have a small amount present as regular thyroid function requires it. If levels are higher in concentration and are accompanied by the signs and symptoms listed here, then be sure to speak with a medical provider right away about the benefits of this test and if it could be right for you.