Calcitonin: Blood Test and Levels Explained

What Is Calcitonin?

Calcitonin is a hormone produced by the thyroid gland. It helps regulate calcium levels in the blood. 

This hormone works by lowering calcium levels when they are too high. It does this by reducing calcium release from bones and increasing calcium excretion through the kidneys. Calcitonin works alongside other hormones, such as parathyroid hormone, to help maintain calcium balance in the body.

Calcitonin is also used as a tumor marker. Measuring calcitonin levels helps detect and monitor certain types of thyroid cancer, especially medullary thyroid cancer.

When Is Calcitonin Testing Recommended?

Calcitonin testing is usually ordered when thyroid disease or cancer is suspected.

Common reasons include:

• Evaluation of thyroid nodules
• Suspected medullary thyroid cancer
• Family history of thyroid cancer
• Monitoring after thyroid cancer treatment
• Follow-up for abnormal thyroid findings
• Screening in high-risk individuals

How Is Calcitonin Testing Conducted?

Calcitonin is measured through a blood test. A healthcare provider draws blood from a vein in your arm.

The sample is sent to a laboratory to measure calcitonin levels in the bloodstream.

No special preparation is usually required. However, your doctor may advise avoiding certain substances or activities before testing to improve accuracy.

What Are the Normal Calcitonin Levels?

Normal calcitonin levels are generally low in healthy individuals.

Typical reference ranges are:

• Men: 8.4 pg/mL or less
• Women: 5.0 pg/mL or less

Note: The units of measurement and the normal ranges can differ depending on the laboratory and the specific methods used.

What Do High Calcitonin Levels Mean?

High calcitonin levels may indicate abnormal activity in the thyroid gland. In some cases, they are strongly associated with certain cancers.

Possible causes include:

• Medullary thyroid cancer: This is the most important condition linked to elevated calcitonin levels.
• C-cell hyperplasia: An increase in calcitonin-producing cells in the thyroid.
• Other thyroid conditions: Some non-cancerous thyroid disorders may raise levels.
• Chronic kidney disease: Reduced clearance can affect calcitonin levels.
• Certain tumors outside the thyroid: Rare tumors may produce calcitonin.

Recommendations

• Follow up with imaging or biopsy if advised.
• Monitor calcitonin levels over time.
• Seek specialist evaluation for thyroid abnormalities.
• Discuss family history of thyroid cancer with your doctor.

Which Specialist Should You Consult?

A endocrinologist is the main specialist for abnormal calcitonin levels.

Depending on the findings, you may also be referred to:

• An oncologist for cancer evaluation
• A surgeon for thyroid-related procedures
• A primary care physician for ongoing monitoring