Calcitonin (synonyms: hCT, thyrocalcitonin) is a hormone produced by C cells in the thyroid gland. Calcitonin is secreted (released) when calcium levels rise and lowers blood calcium concentrations by inhibiting osteoclasts (cells that break down bone). Furthermore, calcitonin causes delay in gastric emptying and renal (kidney) reabsorption (reuptake) of calcium and phosphate. Calcitonin is the antagonist (opponent) of parathyroid hormone (PTH).
Calcitonin is formed from vitamin D (absorbed/converted from food and UV light) via several intermediate steps.
Calcitonin is a so-called tumor marker. Tumor markers are endogenous substances that are formed by tumors and can be detected in the blood. They can provide an indication of a malignant neoplasm and are used as a follow-up test in cancer aftercare. Calcitonin is not specific for malignant (malignant) disease.
The procedure
Material needed
- Blood serum
- Because of low stability transport of samples preferably frozen (about -20°C).
Preparation of the patient
- Not necessary
Disruptive factors
- None known
Standard values
| Normal values in pg/ml | |
| Women | < 4,6 |
| Men | < 11,5 |
Conversion factor
- Pg/ml x 0.28 = pmol/l
Indications
- Suspicion of thyroid carcinoma (thyroid cancer) – e.g., clarification of a scintigraphically cold nodule (usually echo-poor on ultrasound).
- Family members of patients with medullary thyroid carcinoma.
- Suspected multiple endocrine neoplasia (MEN II) – genetic disease that can lead to various tumors; including thyroid carcinoma.
- Therapy / progress control in the above-mentioned tumor disease.
- Therapierefraktäre diarrhea (therapy-resistant diarrhea).
- Unclear CEA elevation (is also often elevated in C-cell carcinomas).
Interpretation
Interpretation of increased values
- Medullary thyroid carcinoma (C-cell carcinoma; thyroid cancer) (> 95% probability of presence of medullary thyroid carcinoma, > 26 pg/mL in women and > 60 pg/mL in men)
- Approximately 50% of cases have concomitant pheochromocytoma
- In 20-30% of cases there is concomitant hyperparathyroidism
- Hypergastrinemia – increased level of a hormone produced in the stomach, which stimulates gastric acid secretion.
- Paraneoplastic hypercalcemia (excess calcium; may also be reactive).
- Pheochromocytoma
- Renal insufficiency (kidney weakness)
Interpretation of decreased values
- No diagnostic significance
