Calcitonin is a hormone produced in the thyroid, whose function is to control the amount of calcium that circulates in the bloodstream, through effects such as preventing the reabsorption of calcium from the bones, decrease the absorption of calcium by the intestines and increase excretion by the kidneys.
The main indication for the examination of calcitonin is the detection of a type of cancer of the thyroid called medullary carcinoma of the thyroid, being considered a tumor marker of this disease, since it causes important elevations from hormone. The evaluation of the presence of thyroid C-cell hyperplasia is also another frequent indication, although this hormone may also be elevated in other situations, such as in lung or breast cancer, for example.
As a medicine, the use of calcitonin may be indicated for the treatment of diseases such as osteoporosis, excess calcium in the blood, Paget's disease or reflex dystrophy. If you want to know more about the medicine calcitonin, see what calcitonin is and what its function is.
What is it for
The calcitonin test can be ordered to:
- Screening for the presence of medullary thyroid carcinoma;
- Investigation of C-cell hyperplasia, which are thyroid cells producing calcitonin;
- Evaluation of family members of patients with medullary thyroid carcinoma for early tumor detection;
- Observation of response to treatment of medullary thyroid carcinoma;
- Follow-up of cancer after thyroid withdrawal, since it is expected that the values will be low in case of cure.
Although these are the main indications, it should be remembered that calcitonin can also be increased in other conditions, such as other cancers such as leukemia, lung cancer, pancreas, breast or prostate cancer in the presence of chronic kidney disease, during a bacterial infection, hypergastrinemia, or as a result of hypercalcaemia by hyperparathyroidism or other conditions.
How is the exam done?
The calcitonin dosage is done in the laboratory, at the request of the physician, where a sample of blood is collected, to obtain its basal levels.
Calcitonin values are influenced by a number of conditions, including use of certain medications, such as Omeprazole or corticosteroids, age, pregnancy, smoking, and alcoholism, so one way to make the test more reliable is by performing calcium infusion or pentagastrin test, which are not potent stimulators of calcitonin secretion.
Calcitonin stimulation test with calcium infusion is the most available, and is carried out in the morning, in the fasted state. Calcium is injected into the vein at 0, 2, 5 and 10 minutes after infusion to assess whether the growth pattern is considered normal or not.
How to evaluate the test result
Calcitonin standard reference values may vary according to the laboratory performing the test. It may be considered as normal value that below 8.4 pg / ml in man and 5 pg / ml in woman. After stimulation with calcium, it can be considered as normal value that below 30 pg / ml and positive when above 100 pg / ml. Between 30 and 99 pg / dl, the test is considered indeterminate, and further tests should be performed to confirm the disease.
