Calcitonin test

A calcitonin test measures the calcitonin level in a sample of your blood. Calcitonin is a hormone that helps control the calcium level in your blood. Calcitonin is produced in your thyroid gland by cells called “C cells.” Your thyroid is a small butterfly-shaped gland located in your neck.

Normally, you have a small amount of calcitonin in your blood. But if you have too many, it can be a sign of:

• Medullary thyroid cancer (CMT), a rare cancer that occurs when the C cells in your thyroid grow out of control. C cells grow in the inner part of your thyroid, which is called the medulla.
• C-cell hyperplasia, a rare condition that causes abnormal growth of C cells in your thyroid. C-cell hyperplasia can develop into medullary thyroid carcinoma.

Your health care provider may order a calcitonin test if you have symptoms of these conditions or if they are present in your family.

Other names: thyrocalcitonin, CT, human calcitonin, hCT

A calcitonin test is most often used to:

• Help diagnose C-cell hyperplasia and medullary thyroid cancer in people with symptoms
• Determining whether the treatment of medullary thyroid cancer is effective
• Check if medullary thyroid cancer has come back after treatment
• Screening for people who are at high risk for medullary thyroid cancer. The risk is high for people with a family history of a rare genetic disorder called multiple endocrine neoplasia type 2 (MEN 2).

There are various types of MEN 2 that often cause tumors in certain glands that produce hormones, including your thyroid. All types of MEN 2 increase your risk of medullary thyroid cancer. MEN2 is caused by changes in a gene called RET. Changes in genes are also referred to as genetic variants or mutations.

You can inherit MEN 2 - and an increased risk of medullary thyroid cancer - if one of your parents passed on a gene to you RET modified. If MEN2 is present in your family, regular calcitonin tests may help detect cancer early, when it may be easier to treat.

You may need a calcitonin test to help check for medullary thyroid cancer or C-cell hyperplasia if:

• You have symptoms of either condition that may include:
  • A mass at the front of your neck
  • Swollen lymph nodes in your neck (also called “swollen glands”)
  • A pain in your throat
  • Difficulty swallowing or breathing
  • A change in your voice, such as hoarseness
  • A persistent cough when you don't have a cold
  • Diarrhea
• You have symptoms of multiple endocrine neoplasia type 2 (MEN 2). MEN 2 can affect your thyroid, adrenal, and parathyroid glands. The symptoms depend on which glands are affected. They may include:
  • Fatigue
  • Depression
  • Pain in bones and joints
  • Nausea and vomiting
  • Increased thirst and urination (urination)
  • High blood pressure
  • Headaches
  • Arrhythmia (a problem with your heart's rhythm or frequency)
  • Perspiration
• You have a family history of MEN 2, which increases your risk of developing medullary thyroid cancer. If MEN2 is present in your family, you and your family members, including children, may need regular calcitonin tests to help find cancer before you have symptoms. Your doctor may also suggest a blood test to check for changes in your genes. RET that cause MEN 2.

If you have been diagnosed with medullary thyroid cancer, you will need calcitonin tests to:

• Determine the effectiveness of your treatment.
• Check to see if the cancer has come back after your treatment is over.

You may need to fast (not eat or drink) for several hours before the test. Your provider will let you know if you need to fast and if there are any special instructions to follow.

There are very few risks in taking a blood test. You may feel a slight pain or bruise where the needle was inserted, but most symptoms go away quickly.

The meaning of your calcitonin test results depends on what you were tested for. If you have had a calcitonin test:

To help diagnose or screen for medullary thyroid cancer or C-cell hyperplasia:

• A normal calcitonin level may mean that you don't have either condition, but that doesn't rule them out. This is because medullary thyroid cancer and C-cell hyperplasia don't always cause high calcitonin. Your provider may request additional tests to find out more.
• A high calcitonin level means that the C cells in your thyroid are making too much calcitonin. The higher the level, the more likely you are to have medullary thyroid cancer or C cell hyperplasia. But high levels of calcitonin can be caused by other conditions, including certain other cancers, certain medications, and pregnancy. To make a diagnosis, your provider will consider additional information, including additional test results.
• A low calcitonin level is not known to be a medical problem.

To monitor treatment for medullary thyroid cancer or to see if the cancer has come back after treatment: The meaning of your test results depends on the type of treatment you are receiving or have received. Treatment usually starts with surgery to remove your thyroid gland. Other treatments include radiation therapy, chemotherapy, and/or medication.

In general:

• Calcitonin levels that decrease and stay low over time usually mean that your treatment is working.
• A calcitonin level that decreases but is even higher than normal may mean that you still have some cancerous tissue left in your body. You may need more tests and treatments.
• A calcitonin level that increases over time It usually means that your cancer has come back or spread to other parts of your body.

Ask your provider to explain what your test results mean for your health.

Learn more about lab tests, reference ranges, and understanding results.

In some cases, your provider may request a more accurate type of calcitonin test called a “calcitonin stimulation test.” For this test, a blood sample will be taken as usual. Next, you will be given a medication to make your body produce calcitonin. The medication is injected into a vein intravenously (IV). After that, additional blood samples will be taken several minutes apart. If your calcitonin increases a lot in each blood sample, it may mean you have C-cell hyperplasia or medullary thyroid carcinoma, but you'll need more tests to be sure.

1. American Cancer Society [Internet]. Atlanta: American Cancer Society Inc.; c2022. Tests for thyroid cancer; [updated May 5, 2020; accessed November 23, 2022]; [approximately 4 screens]. Available at: https://www.cancer.org/cancer/thyroid-cancer/detection-diagnosis-staging/how-diagnosed.html
2. American Cancer Society [Internet]. Atlanta: American Cancer Society Inc.; c2022. What is thyroid cancer? ; [updated on March 14, 2019; accessed on November 23, 2022]; [approximately 4 screens]. Available at: https://www.cancer.org/cancer/thyroid-cancer/about/what-is-thyroid-cancer.html
3. Cleveland Clinic: Health Library: Diagnostics and Tests [Internet]. Cleveland (OH): Cleveland Clinic; c2022. Calcitonin; [revised February 3, 2022; accessed December 5, 2022]; [approximately 10 screens]. Available at: https://my.clevelandclinic.org/health/articles/22330-calcitonin
4. Cleveland Clinic: Health Library: Diagnostics and Tests [Internet]. Cleveland (OH): Cleveland Clinic; c2022. Medullary thyroid cancer (MTC); [revised April 28, 2022; accessed December 5, 2022]; [approximately 13 screens]. Available at: https://my.clevelandclinic.org/health/diseases/22873-medullary-thyroid-cancer-mtc
5. Cleveland Clinic: Health Library: Diagnostics and Tests [Internet]. Cleveland (OH): Cleveland Clinic; c2022. Multiple Endocrine Neoplasia (MEM); [revised May 23, 2022; accessed December 5, 2022]; [approximately 22 screens]. Available at: https://my.clevelandclinic.org/health/diseases/23088-multiple-endocrine-neoplasia-men
6. Konstantakos AK. Medullary thyroid carcinoma. [Updated June 14, 2022; accessed December 5, 2022]. In Medscape: Drugs and Diseases: Oncology [Internet]. Atlanta (GA): WebMD LLC; c1994-2022. Available at: https://reference.medscape.com/article/282084-overview
7. Master SR, Burns B. Medullary thyroid cancer. [Updated September 26, 2022; accessed December 5, 2022]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; Jan. 2022 Available at: https://www.ncbi.nlm.nih.gov/books/NBK459354/
8. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998-2022. Thyroid Cancer: Diagnosis and Treatment; [accessed November 23, 2022]; [approximately 15 screens]. Available at: https://www.mayoclinic.org/diseases-conditions/thyroid-cancer/diagnosis-treatment/drc-20354167
9. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998-2022. Thyroid Cancer: Symptoms and Causes; [accessed November 23, 2022]; [approximately 14 screens]. Available at: https://www.mayoclinic.org/diseases-conditions/thyroid-cancer/symptoms-causes/syc-20354161
10. Mayo Clinic: Mayo Medical Laboratories [Internet]. Mayo Foundation for Medical Education and Research; c1995-2022. Test ID: CATN: Calcitonin, serum: Clinical and interpretive; [accessed November 23, 2022]; [approximately 3 screens]. Available at: https://www.mayocliniclabs.com/test-catalog/overview/9160#Clinical-and-Interpretive
11. National Cancer Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; NCI Dictionary of Cancer Terms: Calcitonin; [accessed November 23, 2022]; [approximately 3 screens]. Available at: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/calcitonin
12. National Cancer Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; NCI Dictionary of Cancer Terms: Multiple Endocrine Neoplasia Syndrome Type 2; [accessed November 23, 2022]; [approximately 3 screens]; [approximately 3 screens]. Available at: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/multiple-endocrine-neoplasia-type-2-syndrome
13. National Cancer Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Pheochromocytoma; [posted February 12, 2020; accessed December 5, 2022]; [approximately 3 screens]; [approximately 3 screens]. Available at: https://www.cancer.gov/pediatric-adult-rare-tumor/rare-tumors/rare-endocrine-tumor/pheochromocytoma
14. National Cancer Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Thyroid Cancer Screening (PDQ (r)) - Patient Version; [updated September 29, 2021; accessed December 5, 2022]; [accessed December 5, 2022]; [approximately 7 screens]. Available at: https://www.cancer.gov/types/thyroid/patient/thyroid-screening-pdq
15. Johns Hopkins Medicine [Internet]. Johns Hopkins University, Johns Hopkins Hospital, and Johns Hopkins Health System; c2022. Health: Blood test; [accessed December 5, 2022]; [approximately 3 screens]. Available at: https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/blood-test
16. National Center for the Advancement of Translational Sciences: Center for Information on Genetic and Rare Diseases [Internet]. Gaithersburg (MD): U.S. Department of Health and Human Services; Multiple Endocrine Neoplasia