Calcitonin

Definition

This test measures the blood level of calcitonin, a hormone secreted by the thyroid gland.

Who is a candidate for the test?

The test is done to rule out disorders of the thyroid gland, as well as kidney failure or liver disease.

How is the test performed?

A blood sample is taken from a vein on the forearm or hand. First, the skin over the vein is cleaned with an antiseptic. Next, a strong rubber tube, or "tourniquet," is wrapped around the upper arm. This enlarges the veins in the lower arm by restricting blood flow through them. A fine needle is gently inserted into a vein, and the tourniquet is removed. Blood flows from the vein through the needle, and is collected in a syringe or vial. After the needle is withdrawn, the puncture site is covered with a bandage for a short time to prevent bleeding. The blood sample is sent to the laboratory to determine the amount of calcitonin circulating in the blood.

What is involved in preparation for the test?

Specific instructions are available from a healthcare professional. Normally, no preparation is required for this test.

What do the test results mean?

Normal levels of calcitonin in the blood range from 0 to 50 picograms per milliliter.

Very high levels of calcitonin in the blood often indicate a specific type of cancer known as medullary carcinoma of the thyroid gland. This malignancy commonly occurs in persons with the multiple endocrine neoplasia syndrome, a rare genetic cancer disorder.

Mildly elevated levels are associated with other cancers or tumors, liver disease, and kidney failure.