Calcitonin is a hormone produced in C cells of the thyroid gland. The thyroid gland is located inside the front of your lower neck above the collar bones. Calcitonin helps control the breakdown and rebuilding of bone. A common reason to have the test is if you have had surgery to remove a thyroid tumor called medullary thyroid cancer. The test allows your health care provider to evaluate if the tumor has spread (metastasized) or has come back (tumor recurrence). Your provider may also order a calcitonin test when you have symptoms of medullary cancer of the thyroid, or multiple endocrine neoplasia (MEN) syndrome, or a family history of these conditions.

What Abnormal Results Mean
A higher-than-normal level may indicate:

• Insulinoma
• Lung cancer
• Medullary cancer of thyroid (most common)
• VIPoma(cancer that usually grows from islet cells in the pancreas) Higher-than-normal levels of calcitonin can also occur in people with kidney disease, smokers, and higher body weight. Also, it increases when taking certain medicines to stop stomach acid production.