Calcitonin

Definition

Calcitonin is a test that measures the amount of the hormone calcitonin in the blood.

Alternative Names

How the test is performed

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

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 symptoms indicate medullary thyroid cancer or MEN syndrome, or the patient has 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 Values

A normal value is less than 10 picograms per milliliter (pg/mL).

It is not uncommon to see different normal values for males and females. 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. This additional test is necessary if the baseline calcitonin value is normal.

NOTE: Normal value ranges may vary slightly among different laboratories. 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

What the risks are

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)

Special considerations

Calcitonin inhibits bone breakdown (resorption) and can be used as a medication to treat several bone diseases and calcium problems, including:

• Hypercalcemia
• Osteoporosis
• Paget's disease

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