Contributed by – Healthians Team

What is the Thyroglobulin test?

Thyroglobulin test, which is also known as Tg, TGB and thyroglobulin tumour marker, measures the level of thyroglobulin present in your blood. Thyroglobulin is a protein manufactured by the cells of your thyroid gland. The thyroid is a small, butterfly-shaped gland situated near your throat. This test is commonly used as a tumour marker test to aid the treatment of thyroid cancer. Tumour markers, also called cancer markers, are substances either produced by the cancer cells or by the normal cells in the body. Thyroglobulin is made by both normal as well as cancerous thyroid cells.

The key aim of thyroid cancer treatment is to get rid of all the malignant thyroid cells from your body. It generally includes surgical removal of the thyroid gland followed by therapy with radioactive iodine. Radioiodine is a medicine which is used to destroy thyroid cells that are left in the body after surgery. It is given as a liquid or in a capsule. No thyroglobulin should be found in your blood post treatment. Assessment of thyroglobulin levels can show whether malignant cells are still present in the body post treatment.

Who should get the test?

You will probably require this test after you’ve been treated for thyroid cancer. Your doctor might test you frequently to see if any thyroid cells remain after treatment. You might be tested every few weeks or months after the treatment ends.

Why is the test needed?

The test is needed to see if your thyroid cancer treatment was successful. If your thyroglobulin levels remain the same or increase after the treatment, then it might mean that cancer cells are still present in your body. If they decrease or disappear after treatment, then it could mean that there are no normal or malignant thyroid cells left in your body.

What does the test result mean?

You might be tested several times over a period of time after your treatment ends. Your results might show that:

  • Your thyroglobulin levels are high or have increased over time. It could mean that thyroid cancer cells are growing or cancer is spreading in your body.
  • No thyroglobulin in your body. It could mean that your cancer treatment has worked and all the thyroid cells have been removed from your body.
  • An increase in thyroglobulin levels overtime after a decrease post treatment. It could mean that your cancer has recurred after successful treatment. In case your reports indicate that your thyroglobulin levels are increasing then your doctor may prescribe an additional radioiodine therapy to remove the remaining cancer cells.
  • A small amount of thyroglobulin in your body. It could be a sign of thyroid cancer, diabetes type 1, some collagen vascular disease and pernicious anaemia which is a drastic decrease in the number of red blood cells in your body due to deficiency of multi-vitamins.

How is the test done?

A health care professional will collect a small amount of blood from a vein in your arm by using a small needle. The sample will be collected in a test tube or vial. The procedure takes less than five minutes. You don’t need to prepare for a thyroglobulin test. However, you might be asked to avoid certain vitamins or supplements.

Take the Thyroglobulin test