What this test measures
Calcitonin is a peptide hormone produced by the parafollicular C-cells of the thyroid gland. Physiologically it lowers blood calcium by inhibiting bone resorption and reducing kidney calcium reabsorption, though its day-to-day role in adult humans is modest — calcium balance is dominated by parathyroid hormone and vitamin D.
Clinically the test is used as a tumour marker. Medullary Thyroid Carcinoma (MTC) arises from C-cells and almost always over-produces calcitonin, making the serum level a sensitive marker of disease presence, burden and recurrence.
Why it matters
MTC accounts for 1–5% of thyroid cancers but is biologically more aggressive than the much commoner papillary and follicular cancers — and an unsuspected MTC behind a thyroid nodule needs a different surgical approach (total thyroidectomy with central neck dissection from the outset). Serum calcitonin is recommended in the workup of any clinically suspicious thyroid nodule, especially when family history of thyroid cancer, hypercalcaemia of unclear cause, or features of Multiple Endocrine Neoplasia type 2 (MEN-2) are present.
For families with a known RET proto-oncogene mutation (MEN-2A, MEN-2B, familial MTC), serial calcitonin monitoring is part of life-long surveillance, and prophylactic thyroidectomy is offered to gene-carriers in childhood. Post-thyroidectomy, calcitonin should be undetectable; any rise is the earliest signal of recurrence, often months before imaging shows disease.
How to prepare
Overnight fasting is preferred. Avoid heavy exercise and alcohol the day before. Stop omeprazole and other proton pump inhibitors for 1 week before testing if clinically possible — chronic PPI use can raise calcitonin. Stop biotin for 48–72 hours. Continue other medications. If a "pentagastrin" or "calcium stimulation" test is planned, your endocrinologist will give specific instructions; the routine assay does not need stimulation.
Markers & reference ranges
Reference ranges below are typical adult values. Your lab's reported range may differ slightly based on the assay platform and patient demographics — always read your report against the range printed on it.
| Marker | Normal range | If low | If high |
|---|---|---|---|
| Calcitonin (pg/mL)[1][2] | Adult male: < 11.5 · Adult female: < 4.6 (assay-dependent; cut-offs vary) | Low or undetectable calcitonin is normal. After thyroidectomy for MTC, undetectable is the goal — it suggests complete disease clearance. | Mild raises (10–100 pg/mL) are seen in chronic kidney disease, chronic PPI use, thyroiditis, and sometimes healthy older men. Raises of 100–1000 pg/mL in someone with a thyroid nodule are highly suspicious for MTC. > 1000 pg/mL essentially confirms MTC and usually indicates distant disease. After thyroidectomy for MTC, any rise above the post-operative baseline is concerning for recurrence. |
Calcitonin — clinical decision bands
| Calcitonin (pg/mL) | Context | Likely meaning |
|---|---|---|
| < 10 | Any | Normal |
| 10 – 100 | No thyroid nodule | CKD, chronic PPI, thyroiditis, smoking — usually benign |
| 10 – 100 | Thyroid nodule present | C-cell hyperplasia or MTC — needs stimulation test / FNAC |
| 100 – 1000 | Thyroid nodule present | High likelihood of MTC — surgical planning |
| > 1000 | Any | MTC with significant tumour burden — imaging for distant disease |
| Detectable (after MTC surgery) | Follow-up | Recurrence until proven otherwise |
Frequently asked questions
Why is calcitonin being checked on me — I do not have cancer?
Calcitonin is most commonly ordered when a thyroid nodule is being worked up, when there is a family history of thyroid cancer or MEN-2, or as part of an evaluation for unusual diarrhoea or flushing (functional MTC). It is not a routine screening test.
My calcitonin is slightly raised but I have no thyroid lump — should I worry?
Mild raises (10–50 pg/mL) are commonly due to chronic kidney disease, long-term proton-pump-inhibitor use, smoking, or thyroiditis. In the absence of a nodule, a repeat after stopping PPIs is usually a reasonable next step.
My doctor mentioned a stimulation test — what is that?
A calcium or pentagastrin infusion can be used to amplify calcitonin secretion when a baseline value is borderline. The stimulated peak is more discriminating between C-cell hyperplasia, MTC and benign causes. Pentagastrin is hard to obtain in India, so calcium-stimulated testing is the usual alternative.
I have had thyroid cancer surgery — why is calcitonin being repeated?
In medullary thyroid cancer, calcitonin is the lifelong tumour marker. After complete surgery it should be undetectable. Any rise is the earliest signal of recurrence — often months before imaging shows disease.
Does PPI medication really affect calcitonin?
Yes. Long-term omeprazole, pantoprazole and other PPIs can double or triple calcitonin. If a raised level is being investigated and there is no thyroid nodule, stopping PPIs for a week and repeating is a standard next step.
I have a family history of MEN-2 — when should I start testing?
In known RET-mutation families, genetic testing of children is offered young, and surveillance starts in early childhood. Prophylactic thyroidectomy is now standard for confirmed gene-carriers — your endocrinologist will plan timing based on the specific mutation.
Does calcitonin tell me about my calcium level?
Not really — although calcitonin physiologically lowers calcium, its day-to-day role in adults is small. Calcium and PTH are far better tests for calcium balance.
Related Hormones / Endocrine tests
Tests commonly ordered alongside CALCITONIN, or that help interpret an unexpected result.
Sources & references
- American Thyroid Association — Medullary Thyroid Carcinoma Guideline · accessed 2026-05-30T00:00:00.000Z
- NIH MedlinePlus — Calcitonin Test · accessed 2026-05-30T00:00:00.000Z
- NCBI StatPearls — Calcitonin · accessed 2026-05-30T00:00:00.000Z
- Mayo Clinic Laboratories — Calcitonin · accessed 2026-05-30T00:00:00.000Z
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