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.
- Specimen
- Serum or plasma
- Measures
- Mass concentration
What you'll learn
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Insights that connect the dots. A clinician reads your whole picture, not one result in isolation, connecting family history, past results, and lifestyle into clear next steps.
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Your personalized action plan. Nutrition, supplements, and training in one clinician-reviewed protocol, updated as your results change.
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Track your trends. Upload results from any lab and see each biomarker trend over time, so you know what is working.
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Never miss a recheck. Mito tells you what is worth retesting and when, then reminds you so nothing slips.
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.
Everything your health needs,
in one membership
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Every test at our cost
Members pay our cost on every test, with lab fees passed straight through. The full receipt is itemized, never padded.
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Continuous tracking, all in one place
Upload past labs and watch your trends over time. Every marker and visit lives in one longitudinal record, so all your care stays together.
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Year-round clinician support
Text anytime and get clinician-reviewed answers. When you want to go deeper, 1:1 consultations are available at affordable rates.
All for $9/month
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. It is never a profit on the test itself. Mito makes its money on the $9 membership, not on marking up your tests. Membership is $9 per month, and any applicable lab order or draw fee is itemized before you pay.
Where do I get tested?
Choose an available partner lab at checkout. If your cart contains multiple blood tests, Mito helps consolidate the eligible tests at one lab when possible. At-home kits and scans follow the collection or appointment process shown on their product page.
Is this eligible for HSA/FSA?
Yes. Eligible tests can be paid for with an HSA or FSA card at checkout.
When will I get my results?
Your results appear in your Mito dashboard after the laboratory completes processing. A clinician then reviews them before your analysis and personalized action plan are finalized. Timing varies by test, and specialty assays and at-home kits may take longer.
Do I need a physician's order?
No. Mito provides the laboratory order when one is required, so you do not need to arrange a separate physician visit before purchasing.
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