Calcitonin

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Also known as: Human calcitonin; Thyrocalcitonin
Formal name: Calcitonin
Related tests: RET Oncogene; Calcium; TSH; FT3; FT4; Thyroglobulin; CEA

At a Glance

Why Get Tested?

To help diagnose and monitor C-cell hyperplasia and medullary thyroid cancer (MTC); to screen those at risk for multiple endocrine neoplasia type 2 (MEN 2)

When to Get Tested?

If your doctor suspects that you have MTC, if you are being treated for MTC, or if a family member has MTC or MEN 2

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

After an overnight fast, a blood sample is obtained by inserting a needle into a vein in the arm. The sample should be collected on ice and transferred to the laboratory for immediate centrifugation.

It is important that the person taking the sample follows the instructions of the local laboratory as different laboratories may require different specimen types. Please contact the local laboratory for details.

The Test Sample

What is being tested?

This test measures the amount of calcitonin in the blood. The function of calcitonin in the human body is unknown; what is known is that it is a hormone produced by C-cells in the thyroid. The thyroid is a small butterfly-shaped gland that lies over and flat against the windpipe in the throat. It produces several hormones, primarily T4 (thyroxine) and T3 (triiodothyronine), that help control the rate of metabolism.

In two rare conditions, C-cell hyperplasia and medullary thyroid cancer (MTC), excessive amounts of calcitonin are produced. C-cell hyperplasia is a benign condition that may or may not progress to become MTC. MTC is malignant – it can spread beyond the thyroid and can be difficult to treat if it is not discovered early.

About 75-80% of MTC cases are sporadic, but about 20-25% are related to an inherited mutation in the RET oncogene that leads to multiple endocrine neoplasia type 2 (MEN 2), a syndrome associated with several related diseases, including MTC. The altered RET oncogene is inherited in an autosomal dominant fashion. This means that only 1 copy of the mutated oncogene, from either your father or mother, is required to have a greatly increased risk of developing MTC. Most cases of sporadic MTC develop when patients are in their 40s or 50s and the prevalence is higher in women, but inherited MTC affects both sexes equally and can occur at an early age.

How is the sample collected for testing?

After an overnight fast, a blood sample is obtained by inserting a needle into a vein in the arm. The sample should be collected on ice and transferred to the laboratory for immediate centrifugation.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

It is important that the person taking the sample follows the instructions of the local laboratory as different laboratories may require different specimen types. Please contact the local laboratory for details.

The Test

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.