Calcitonin — What It Means in Your Blood Test
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Tumour marker results are complex. This page explains what the test measures — your doctor or specialist interprets your result in full clinical context, alongside your history and other tests.
What Calcitonin cannot tell you
Calcitonin is not a routine cancer screen. Kidney disease, some acid-reducing medicines and smoking raise it, and a normal result is reassuring but read in context. A specialist interprets it [ATA, 2015].
This is a hormone from special cells in the thyroid, present in tiny amounts normally.
A mildly raised calcitonin usually comes from kidney disease or certain medicines, not cancer. A specialist reads it with your history and repeats it when needed.
Also known as: Serum calcitonin, CT
This isn't a case where higher or lower is better. Your body keeps it in a narrow band, and both directions can matter.
Last reviewed: 2026-08-16
What does Calcitonin do in your body?
Doctors measure calcitonin to look into an uncommon thyroid cancer and to follow it once known. Everyday causes such as reduced kidney function raise it, so a mild rise is repeated and checked [ATA, 2015].
What is Calcitonin?
Calcitonin is a hormone made by the C-cells of the thyroid. Several ordinary conditions, and one uncommon thyroid cancer, can raise how much appears in the blood.
Why is Calcitonin tested?
You may have this test to look into a thyroid lump or a family history, or to follow a known medullary thyroid cancer. It is read with your history.
What can raise Calcitonin
Common, non-cancer causes
- Reduced kidney function, which raises calcitonin [ATA, 2015]
- Certain acid-reducing (anti-reflux) medicines taken over a long time [ATA, 2015]
- Smoking [ATA, 2015]
- A high blood calcium level [ATA, 2015]
Causes a doctor will also consider
- Medullary thyroid cancer, an uncommon cancer of the thyroid's C-cells, which a specialist looks into when calcitonin is clearly raised [ATA, 2015]
A single mildly raised calcitonin is often repeated before anything else. A specialist reads the level and its trend with your history and an examination [ATA, 2015].
What is a normal Calcitonin range?
- India
- No India-specific national reference interval is published for this parameter; your lab's printed range is the most reliable comparison.
- Global
- Normal calcitonin is very low; laboratories use sex-specific references, and kidney disease or certain medicines can raise it without cancer [ATA, 2015]
Ranges vary by lab, method and equipment — the range printed on your own report is the one that applies to your result.
Source: [ATA, 2015]
What does your Calcitonin value mean?
There is no widely-accepted set of value bands for this parameter. Compare your result with the reference range printed on your own report, and discuss it with your doctor.
What does a high Calcitonin result mean?
A raised calcitonin often reflects reduced kidney function or certain medicines. A specialist weighs these first, and repeats a mild rise, before any next step.
What does a low Calcitonin result mean?
A low or within-range calcitonin is reassuring. It is still read with your history, as no single marker settles a question on its own.
What can affect your Calcitonin result?
- Kidney function
- Certain acid-reducing medicines
- Smoking
- A high blood calcium level
- The laboratory assay
Questions to ask your doctor
About this result
- My Calcitonin is [value] pg/mL — read with my history, how concerned should we be?
- Could my kidney function or a long-term medicine explain my Calcitonin?
What to do next
- Should the Calcitonin be repeated to confirm a mild rise?
- Do my Calcitonin result and examination together point to a next step?
Frequently asked questions
- What is Calcitonin?
- Calcitonin is a hormone made by the C-cells of the thyroid. Several ordinary conditions, and one uncommon thyroid cancer, can raise how much appears in the blood. You may have this test to look into a thyroid lump or a family history, or to follow a known medullary thyroid cancer. It is read with your history.
- What is a normal Calcitonin test (thyroid marker) range?
- A typical adult range is around Normal calcitonin is very low; laboratories use sex-specific references, and kidney disease or certain medicines can raise it without cancer [ATA, 2015]. No India-specific national reference interval is published for this parameter; your lab's printed range is the most reliable comparison. Ranges vary by lab, method and equipment — the range printed on your own report is the one that applies to your result.
- What does a high Calcitonin result mean?
- A raised calcitonin often reflects reduced kidney function or certain medicines. A specialist weighs these first, and repeats a mild rise, before any next step.
- What does a low Calcitonin result mean?
- A low or within-range calcitonin is reassuring. It is still read with your history, as no single marker settles a question on its own.
- What can affect your Calcitonin result?
- Several everyday factors can influence it, including Kidney function, Certain acid-reducing medicines, Smoking, A high blood calcium level, The laboratory assay.
Sources
- ATA (2015) — Revised American Thyroid Association Guidelines for the Management of Medullary Thyroid Carcinoma
Part of the Tumour Markers
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