Calcitonin test for the diagnosis of medullary thyroid carcinoma

This is an automatically translated article.

1. What is Calcitonin test?

Calcitonin is a polypeptide hormone secreted by the parafollicular C cells of the thyroid gland.
This hormone is involved in the regulation of serum calcium and phosphorus levels. When there is an increased level of calcium in the blood, calcitonin is secreted. This hormone inhibits calcium absorption from the gastrointestinal tract, inhibits osteoclasts to reduce bone resorption activity and stimulates the kidneys to increase calcium excretion. The above effects are opposite to those of parathyroid hormone and cause low blood calcium levels.
Calcitonin blood test is also used to screen for medullary thyroid cancer in members with multiple endocrine neoplasia type 2.

2. When do you need a calcitonin test?

The doctor will order the Calcitonin blood test to diagnose medullary thyroid cancers and ectopic thyroid peptide secretion. The test is performed on serum .
Patients are required to fast overnight (12h) before taking samples for testing.

3. Calcitonin test results

The normal (reference) value for serum calcitonin as measured by immunochemiluminescence is < 18.2 pg/mL and in women < 11.5 pg/mL.
When a baseline calcitonin limit of 15-50 pg/mL is considered to be a suspect area (grey zone), for the diagnosis of medullary thyroid cancer, a test to stimulate calcitonin production by injection is required. high dose intravenous calcium.

In the case of indications for calcium infusion when doing a stimulus test (using calcium at a dose of 2.4 mg/kg)
Female. < 130 pg/mL or < 130 ng/L. Male: < 190 pg/mL or < 190 ng/L If the patient is prescribed pentagastrin injection when doing a stimulus test (using pentagastrin at a dose of 0.5 μg/kg)
Female: < 35 pg/mL or < 35 ng /L Male: < 110 pg/mL or < 110 ng/L The calcitonin test is not generally used to screen for thyroid cancer in the general population because of the very low incidence of medullary thyroid cancer ( 5.7/100,000 population/year).
In medullary thyroid cancer, the calcitonin test results are often elevated while the levels of other thyroid function parameters such as TSH, T3, and T4 are normal.

4. Calcitonin test meaning

If the Calcitonin test results are low, the symptoms listed above may not be due to medullary thyroid cancer.

A high level of calcitonin means that an excessive amount of calcitonin is being produced. Significantly elevated levels of calcitonin are a good indicator of medullary thyroid cancer. However, to diagnose, the doctor needs to use a number of other techniques such as: ultrasound, tomography, and to confirm the diagnosis, it is necessary to biopsy the thyroid gland with a fine needle and then stain the specimen to find cancer cells. letters.
Calcitonin test results may also be elevated in certain other cancers such as: Lung, breast and pancreatic cancers or insulin tumors (insulinomas). In addition, a mild calcitonin level in the suspected region (15-50 pg/mL) may also be seen in autoimmune thyroiditis with C-cell hyperplasia or in neuroendocrine tumors. neuroendocrine tumours).
The level of calcitonin can be affected when the average person uses certain drugs such as epinephrine, glucagon, oral contraceptives.
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