Definition
This is a test that measures the amount of the hormone calcitonin in the blood.
Why the Calcitonin is Performed
The health care provider may suggest a calcitonin test when he/she suspects medullary thyroid cancer. Calcitonin may also be elevated in other tumors such as insulinomas, VIPomas, and lung cancer.
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 opposition to parathyroid hormone (PTH) and 1,25-dihydroxy vitamin D.
How the Calcitonin is Performed
Blood is drawn from a vein on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill with blood.
A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. After the blood is drawn, the band is removed to restore circulation. Then, the needle is removed, and the puncture site is covered to stop any bleeding.
For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.
How to Prepare for the Calcitonin
There is no special preparation.
For infants and children:
The preparation you can provide for this test depends on your child's age and experience. For specific information regarding how you can prepare your child, see the following topics:
- infant test or procedure preparation (birth to 1 year)
- toddler test or procedure preparation (1 to 3 years)
- preschooler test or procedure preparation (3 to 6 years)
- schoolage test or procedure preparation (6 to 12 years)
- adolescent test or procedure preparation (12 to 18 years)
How the Calcitonin 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.
Risks
The risks associated with having blood drawn are:
- bleeding
- fainting or feeling lightheaded
- hematoma (blood accumulating under the skin)
- infection (a slight risk any time the skin is broken)
- multiple punctures to locate veins
Considerations
Calcitonin inhibits bone resorption and can be used as a medication to treat several bone diseases and calcium problems, including osteoporosis, Paget's disease, and hypercalcemia (high blood calcium).
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.
Normal Results
A normal value is less than 10 pg/ml (picograms per milliliter).
Note: Normal ranges may differ by the laboratory of the health care provider; it is not uncommon to see different normal values for males and females. Sometimes, health care providers obtain 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. This additional test would be necessary if the health care provider's suspicion was very high but the baseline calcitonin value was normal.
What Abnormal Results Mean
Greater-than-normal levels may indicate:
- medullary carcinoma of thyroid
- insulinoma
- VIPoma
- lung cancer
