Calcitonin Blood Test: Thyroid C-Cell Marker
Calcitonin is a peptide hormone produced by the parafollicular C cells of the thyroid gland. It plays a role in calcium and bone metabolism by opposing the action of parathyroid hormone. Clinically, the calcitonin blood test is most commonly used as a tumour marker for medullary thyroid carcinoma (MTC), a rare type of thyroid cancer originating in the C cells. It may also be ordered when evaluating thyroid nodules or monitoring patients after thyroid cancer treatment.
Why Test Calcitonin Blood Test?
Calcitonin testing is indicated when medullary thyroid carcinoma is suspected, when thyroid nodules require further evaluation, or for ongoing surveillance in patients with a personal or family history of MTC or multiple endocrine neoplasia (MEN) syndromes. It is also used postoperatively to monitor for recurrence after thyroid cancer surgery.
What Do High Calcitonin Blood Test Levels Mean?
Elevated calcitonin levels may indicate medullary thyroid carcinoma, C-cell hyperplasia, or other conditions that stimulate C-cell activity. The degree of elevation often correlates with tumour size and burden. Mildly elevated levels can sometimes be caused by other factors, including chronic kidney disease, other cancers, and certain medications. A significantly raised calcitonin warrants further investigation, including imaging and potential biopsy.
What Do Low Calcitonin Blood Test Levels Mean?
Low or undetectable calcitonin levels are considered normal and indicate that C-cell activity is within the expected range. After successful treatment for medullary thyroid carcinoma, low calcitonin is a favourable indicator suggesting no residual disease.
Symptoms to Watch For
- Thyroid nodule detected on examination or imaging
- Persistent hoarseness or voice changes
- Difficulty swallowing
- Lump or swelling in the neck
- Unexplained diarrhoea (in advanced MTC)
- Facial flushing (in advanced MTC)
Who Should Get Tested?
- Individuals with thyroid nodules requiring further workup
- People with suspected or confirmed medullary thyroid carcinoma
- Those with a family history of MTC or MEN syndromes
- Patients post-thyroidectomy for MTC, to monitor for recurrence
- Individuals with RET gene mutations
How to Prepare for Your Test
No special preparation is needed. Bring valid identification to your appointment.
Order Your Blood Test
Test your Calcitonin Blood Test levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.
Frequently Asked Questions
Is calcitonin only related to thyroid cancer?
How is calcitonin different from other thyroid tests?
Can calcitonin levels be used to monitor treatment?
Reviewed by
Wellth Team
Wellth
Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.
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The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.