The Serum Calcitonin Blood Test: An Overview

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What Is Calcitonin?

Calcitonin is a one of the major hormones of the body that can be used to regulate calcium and bone metabolism. It is produced in the medullary region of the thyroid gland, the organ that sits right at the front of the throat.

Calcitonin can only be produced by the body, and it is released from the thyroid gland after detecting that the blood level of calcium is too high. Calcitonin is an antagonist to parathyroid hormone which is a hormone produced by the parathyroid glands and used to increase the level of calcium in the blood.

In instances where a person might be suspected of having a high calcitonin level, a sample of blood will be removed and tested for overproduction of calcitonin by the thyroid gland. High calcitonin is a prevalent sign of people with C-cell hyperplasia and medullary thyroid carcinoma.

Why Is The Test Ordered?

The serum calcitonin blood test level is obtained after someone has visited their doctor and the doctor suspects that their current signs and symptoms point to high calcitonin levels.

The test is used as an initial diagnosis of enlargement of cells in the medullary region of the thyroid gland. These cells produce calcitonin, and if they become enlarged for some reason, there will be an increase in the serum calcitonin blood test level. This test is also used as an initial diagnosis of primary cancer within the thyroid gland, or secondary cancer that has spread to the thyroid gland.

Another reason why the test can be ordered is to monitor the recurrence of C-cell hyperplasia or thyroid cancer. In either instance the physician will need to know if treatment has been effective and if the hyperplasia or cancer has returned. Thus many in the healthcare industry use the calcitonin test as a way of confirming if treatment for thyroid hyperplasia and cancer has been effective.

How is The Test Performed?

The serum level of calcitonin is carried out by drawing blood by venipuncture. Venipuncture is a simple and quick process that is done either by a doctor or a phlebotimist in a laboratory setting. It just involves taking blood from the junction of the arm and forearm. The sample is collected within a plastic tube, and tested for its calcitonin level.

Blood Test Results For Calcitonin

A high serum calcitonin blood test level is indicated of a problem with the medullary cells of the thyroid gland. Even a high calcitonin level, it is expected that the other hormones produced by the thyroid gland such as thyroxine should be at a normal level. A high calcitonin level can mean either an enlargement of cells or the formation of cancer in that area. Surgery is usually the treatment of choice in the case of cancer, but in instances where the calcitonin level remains elevated after removal, the physician will have to review the patient for areas where cancerous thyroid cells might have migrated to other organs.


Print Source: Davidson, Stanley & C. Haslett. 2002. “Davidson’s Principles and Practice of Medicine.” Churchill Livingstone, Edinburgh.

Print Source: Cotran R, Kumar V, and Robbins, SL. 1999. Robbins Pathologic Basis of Disease, 6th Ed. W.B. Saunders Company, Philadelphia.

Web Source: Lab Tests Online, American Association For Clinical Chemistry. “Calcitonin: Test Sample.” 2010. Available: