Calcitonin
Hormone made by the C cells of the thyroid, a marker for medullary thyroid cancer
Also known as
Definition
Calcitonin is a hormone made by the C cells of the thyroid gland. It is released when blood calcium rises and is involved in the breakdown and rebuilding of bone. In the lab, the measurement is mainly used to help assess C-cell hyperplasia or medullary thyroid cancer and to monitor the course after treatment of this cancer.
| Parameter | Value |
|---|---|
| Unit | pg/mL (ng/L) |
| Reference Range | Typical for adults: men below 25 pg/mL, women below 20 pg/mL. Labs differ depending on the assay; the reference range on your own report is what counts. Discuss your result with your doctor. |
Agree on your personal target range with your doctor.
1 pg/mL equals 1 ng/L. European reports often use ng/l.
↓ What a low value means
A low calcitonin level is not known to cause health problems. A normal value does not reliably rule out C-cell hyperplasia or medullary thyroid cancer, because these do not always raise calcitonin. In follow-up after treatment, a value that falls and stays low is usually taken as a sign that treatment is working. Discuss your result with your doctor.
↑ What a high value means
A raised value means the C cells are producing more calcitonin. It may be related to C-cell hyperplasia or medullary thyroid cancer; the higher the value, the more likely such a link becomes. Increases also occur for other reasons, for example with kidney disease, in people who smoke, with higher body weight, during pregnancy, with medicines that suppress stomach acid, and with some other tumors. A value that rises again after treatment may point to a recurrence. Interpretation relies on further findings and belongs with your doctor.
When to test
Calcitonin is measured with symptoms such as a lump in the neck, swollen neck lymph nodes, persistent hoarseness or trouble swallowing, with a family history of MEN 2 or medullary thyroid cancer, and in follow-up after treatment of this cancer. Your practice will tell you whether to fast. A stimulation test with several blood draws sometimes follows.
Frequently asked questions
How does a calcitonin stimulation test work? +
First a baseline value is measured. You then receive a medicine through a vein that stimulates calcitonin production, and several further blood samples track how the level responds. The test is considered when the baseline value is normal but medullary thyroid cancer still needs to be investigated.
Why do men and women have different cut-offs? +
On average, men have higher calcitonin levels than women. Labs therefore give separate upper limits, which also vary by assay.
Does a raised calcitonin level automatically mean cancer? +
No. Besides changes in the C cells, kidney disease, smoking, higher body weight, pregnancy or acid-suppressing medicines can raise the value. Your doctor evaluates it together with other tests.
Is calcitonin measured routinely in everyone? +
No. General screening is not usual because the conditions in question are rare. The value is measured in specific situations, such as thyroid findings, a family history or follow-up care.
Calcitonin
Sources
Last updated: October 05, 2026
This information is for orientation only and does not replace medical advice. Reference ranges can vary by laboratory, method and country.