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Calcitonin
Definition
Calcitonin is a test that measures the amount of the hormone calcitonin in the blood.
How the Test is Performed
A blood sample is needed. For information on how this is done, see: Venipuncture
How to Prepare for the Test
There is usually no special preparation needed.
How the Test Will Feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed
The health care provider may suggest a calcitonin test when you have symptoms of medullary thyroid cancer or MEN syndrome, or a family history of these conditions. Calcitonin may also be higher in other tumors, such as:
- Insulinomas
- Lung cancer
- VIPomas
Calcitonin is a hormone produced in the C cells of the thyroid gland. Its role in humans is unclear. In animals, calcitonin helps to regulate blood calcium by slowing down the amount of calcium released from the bones. Calcitonin works in the opposite way as parathyroid hormone (PTH) and 1,25-dihydroxy vitamin D.
Normal Results
A normal value is less than 10 picograms per milliliter (pg/mL).
Males and females can have different normal values. Sometimes, health care providers take a second or even a third calcitonin blood level after an intravenous (IV) infusion of calcium, especially when the health care worker suspects medullary carcinoma of the thyroid. You will need this extra test if your baseline calcitonin is normal.
The examples above are common measurements for results for these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different specimens. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
Higher-than-normal levels may indicate:
- Insulinoma
- Lung cancer
- Medullary carcinoma of thyroid
- VIPoma
Risks
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Reviewed By: Nancy J. Rennert, MD, Chief of Endocrinology & Diabetes, Norwalk Hospital, Associate Clinical Professor of Medicine, Yale University School of Medicine, New Haven, CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
