Calcitonin
The blood marker that tracks medullary thyroid carcinoma and the C-cell tumors behind it.
Consider this test if:
- A family history of medullary thyroid carcinoma or multiple endocrine neoplasia type II
- Monitoring after thyroidectomy for medullary thyroid carcinoma and watching for recurrence
- A calcified thyroid nodule, or a thyroid mass with hypercalcemia or pheochromocytoma
- Unexplained secretory diarrhea or flushing alongside a known thyroid tumor
- A confirmed RET mutation and the need to track C-cell status over time
- HSA/FSA eligible
- Typical results in 3-5 days · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you ·
Pre-test considerations
Fasting is required. The sample must be separated, frozen promptly, and kept frozen, so it is drawn at a lab that can handle frozen serum. Hemolysis and lipemia invalidate the result, and baseline levels can be normal in early or familial disease, where provocative calcium or pentagastrin stimulation testing is the more sensitive approach.
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What this test is for
Calcitonin is a hormone secreted by the C cells (parafollicular cells) of the thyroid, and in clinical practice it serves mainly as a tumor marker for medullary thyroid carcinoma (MTC) and its precursor, C-cell hyperplasia. Elevated levels point toward MTC, including the inherited forms tied to multiple endocrine neoplasia type II (alongside pheochromocytoma and hyperparathyroidism), and preoperative levels roughly correlate with tumor extent, which makes calcitonin valuable for staging, post-surgical monitoring, and detecting recurrence by tracking its doubling time. It is not a general screening test: elevations also occur with lung, breast, and islet-cell tumors, pancreatitis, thyroiditis, renal failure, and Zollinger-Ellison syndrome, and hemolysis can cause spuriously high readings. In early or familial disease the baseline value can be normal, so provocative calcium or pentagastrin stimulation is often needed to unmask abnormal C-cell activity. A rising calcitonin after thyroidectomy is one of the earliest signals of recurrent or residual medullary carcinoma.
What to expect
- 1 Book instantly
Click, book, done. Choose a convenient lab location near you. Transparent, up-front pricing.
- 2 Quick lab visit
Testing to fit your busy schedule, usually 15 minutes or less. Walk-in and appointments available.
- 3 Typical results in 3-5 days
Your results post straight to your dashboard as soon as the lab completes them.
- 4 Expert guidance
Included with Mito membership. A clinician reviews your results and your personalized action plan follows, with clear next steps.
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Members pay our cost on every test, with lab fees passed straight through. The full receipt is itemized, never padded.
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Order any test or consult without joining. For $9/month, members unlock member prices, trend tracking, and year-round clinician guidance.
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Frequently asked questions
View all FAQsHow does pricing work?
Every test shows the member price next to the standard non-member price, so you can see what membership saves you. The member price is our cost — covering the lab and what it takes to run the service — never a profit on the test itself; Mito makes its money on the $9 membership, not on marking up your tests. Membership is $9/mo, and you still pay the lab’s order fee. Prices are itemized before you pay, with no hidden fees.
Where do I get tested?
Choose a partner lab (Quest, Labcorp, or BioReference) at checkout. If your cart spans multiple tests, we consolidate the whole order onto a single lab so you only make one visit.
Is this eligible for HSA/FSA?
Yes. This test is HSA/FSA eligible, and you can pay with your HSA/FSA card at checkout.
When will I get my results?
Your results post to your dashboard once your lab completes them, then a clinician reviews them and your full analysis and personalized action plan (with clear next steps) follow. Turnaround varies by test: specialty assays and at-home kits take longer, and each test shows its expected turnaround before you buy.
Do I need a doctor’s order?
No. Mito provides the lab order for you, so you can book and get tested without a separate doctor visit.
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