Thyroglobulin - Blood test measures the levels of thyroglobulin in the blood. Thyroglobulin (Tg) is a protein produced by the cells of the thyroid gland. This protein is the main source of triiodothyronine (T3) and thyroxine (T4). These hormones are also produced by the thyroid gland. They help to control the rate at which energy is used in almost every tissue in the body. Normally, the blood will contain very low levels of thyroglobulin. Abnormal levels of thyroglobulin levels in the blood may indicate thyroid dysfunction.
Why this test is performed?
This test is one amongst many tests that may be helpful to determine if the thyroid gland is functioning normally. The thyroid gland is a part of the endocrine system. It produces and releases the thyroid hormones into the bloodstream. The hormones produced by the thyroid gland regulate various functions in the body including heart function, digestive function, bone maintenance, brain development, muscle control, metabolism (the rate at which the body uses energy), etc.
This test is used to identify if the thyroid gland is hyperactive (hyperthyroidism) or underactive (hypothyroidism). Hyperthyroidism is a condition where the thyroid gland produces too many hormones. This condition may cause signs and symptoms such as a sudden weight loss, irritability, sweating, irregular heartbeats, etc. Hypothyroidism is a condition where the thyroid gland does not produce enough amount of hormones. This condition may cause signs and symptoms such as a sudden weight gain, dry skin, constipation, feeling cold, slow heart rate, etc. Your doctor may ask you to undergo this test if you are suffering from any such symptoms. However, your doctor may recommend a few more additional thyroid tests to diagnose certain thyroid disorders.
Your doctor may ask to perform this test to evaluate the treatment response of thyroid cancer. This test is also recommended to perform at intervals after the treatment of thyroid cancer to monitor for cancer recurrence.
If you are suffering from a thyroid disorder and receiving treatment for the same, your doctor may advise you to undergo this test as part of routine monitoring as well as to determine the effectiveness of the treatment.
If you are an otherwise healthy individual and the test results are in the normal range, then the thyroid gland is functioning normally and there is no need for medical intervention. If you have been diagnosed with a thyroid disorder and the test results are in the normal range, then the treatment you are receiving is working effectively.
Inform your doctor if you are on any medications, have any allergies or underlying medical conditions before your TG. Your doctor will give specific instructions depending on your condition on how to prepare for TG.
No specific preparation is necessary for this test. However, if it is performed along with other blood tests, you may need to fast (not eat or drink) for several hours, as instructed by the doctor.
If the thyroglobulin levels are above the normal range, it may be indicative of hyperthyroidism. Certain conditions such as thyroiditis (inflammation of the thyroid gland), etc. may also be responsible for the increased levels of thyroglobulin protein in the blood. Sometimes thyroglobulin levels will be elevated in individuals with thyroid cancer.
If the thyroglobulin levels are below the normal range, then it may be indicative of hypothyroidism. Decreased thyroglobulin levels in individuals receiving treatment for Graves disease may indicate a positive response to the treatment
Individuals who had undergone surgical removal of the thyroid and/ or after radioactive iodine therapy may show no or very low thyroglobulin levels in their blood. Presence of thyroglobulin in individuals who had undergone surgical removal of the thyroid may indicate thyroid cancer recurrence.
If you have abnormal thyroglobulin levels in the blood consult your doctor for further instructions. Based on the test results, your doctor may advise appropriate medical treatments or further diagnostic tests.
|OTHER||All age groups||0.5 - 1 ng/ml|