Calcitonin
A hormone from thyroid C-cells that lowers blood calcium — and the tumour marker for medullary thyroid carcinoma.
Clinically, its main use is screening for medullary thyroid cancer. Relevant safety context: GLP-1 agonists carry a boxed warning for thyroid C-cell tumours based on rodent data, and are contraindicated with a personal or family history of MTC or MEN2.
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Unlock everything — $10/mo →📚 GLP-1 receptor agonist prescribing information — boxed warning. American Thyroid Association MTC guidelines.
🩸 Test your Calcitonin
Order directly through Marek Diagnostics — no doctor's visit needed, drawn at any Quest location in the US. Code CAMERON applies 10% off automatically.
Order this test — 10% off → Browse all 102 markers →What Calcitonin is usually tested alongside
On its own, one marker is a data point. These panels include Calcitonin plus the markers that make it interpretable — each names every test, why it is on the list, and loads the whole set into your cart in one click at 10% off.
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Would you feel it? Symptoms Calcitonin helps explain
People rarely search for a marker — they search for how they feel. These are the complaints where this marker is worth checking, and whether it is a first-line test or a follow-up once the obvious causes are ruled out.
Why your Calcitonin might be wrong
Most abnormal results are interference, not disease. These are the things that measurably move this specific marker — check them before you change anything. Each one says whether the number is wrong and should be repeated, badly timed and should be redrawn, or real with a cause worth explaining.
Chronic PPI use raises calcitonin modestly and is a recognised cause of a mildly abnormal result.
Note PPI use before any thyroid investigation.
Both raise calcitonin without medullary thyroid cancer — impaired clearance in kidney disease and a genuine stimulatory effect from smoking.
Interpret against eGFR and smoking status before any thyroid workup.
What Calcitonin means in combination
A single marker tells you a little. Combinations tell you the story — these are the named patterns this marker takes part in, and what each one points at.
Tumour markers are monitoring tools, not screening tests, and every one of them rises in benign conditions. CA-125 with endometriosis, fibroids or any peritoneal irritation. CEA with smoking. CA 19-9 with gallstones and any biliary obstruction. Calcitonin with chronic PPI use and kidney impairment.
Interpret only in context, and never as a screen. The trend across serial measurements matters far more than one value.
What to test next
Markers rarely answer alone. These are the ones that put Calcitonin in context — each with its own full breakdown.
Frequently asked questions
<8.4 pg/mL Ranges vary by laboratory and assay — always compare to the range printed on your own report.
Optimal ranges, root causes and the full correction protocol are available inside Coach Cam's Peptide Academy.
See the full breakdown inside the Academy.
See the full breakdown inside the Academy.
You can order Calcitonin directly through Marek Diagnostics without a doctor's visit — drawn at any Quest Diagnostics location in the US. Code CAMERON applies 10% off automatically.