This test measures the blood level of calcitonin, a hormone secreted by the thyroid gland.
The test is done to rule out disorders of the thyroid gland, as well as kidney failure or liver disease.
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 After the needle is withdrawn, the puncture site is covered with a bandage for a short time to prevent bleeding.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.
Specific instructions are available from a healthcare professional. Normally, no preparation is required for this test.
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.