Calcitonin is a hormone produced in the thyroid, whose function is to control the amount of calcium circulating in the bloodstream, through effects such as preventing the reabsorption of calcium from bones, decreasing the absorption of calcium by the intestines and increasing excretion by the kidneys.
The main indication for the calcitonin test is the detection of a type of thyroid cancer called medullary thyroid carcinoma, being considered a tumor marker of this disease, as it causes important elevations of this hormone. The assessment 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 lung or breast cancer, for example.
As a medicine, the use of calcitonin can be indicated for the treatment of diseases such as osteoporosis, excess calcium in the blood, Paget's disease or reflex systematic dystrophy. If you want to know more about calcitonin, see what calcitonin is and what it does.
What is it for
The calcitonin test can be ordered for:
- Screening for the existence of medullary thyroid carcinoma; Investigation of C-cell hyperplasia, which are calcitonin-producing thyroid cells; Evaluation of family members of medullary thyroid carcinoma, for early detection of the tumor; Observation of the response to the treatment of the carcinoma thyroid medulla; Monitoring of cancer after thyroid removal, as it is expected that the values are 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 types of cancer, such as leukemia, lung cancer, pancreas, breast or prostate, in the presence of chronic kidney disease, during a bacterial infection, hypergastrinemia, or as a result of hypercalcemia due to hyperparathyroidism or other conditions.
How the exam is done
Calcitonin dosage is done in the laboratory, at the doctor's request, where a blood sample is taken to obtain baseline levels.
Calcitonin values are influenced by several conditions, which include the use of certain medications, such as Omeprazole or corticosteroids, age, pregnancy, smoking and alcohol consumption, so a way to make the test more reliable is to perform it together with the Calcium or pentagastrin infusion test, other than potent stimulators of calcitonin secretion.
The calcitonin stimulus test with calcium infusion is the most available, and is performed in the morning, on an empty stomach. Calcium is injected through the vein, at 0, 2, 5 and 10 minutes after the infusion, to assess whether the increase pattern is considered normal or not.
How to evaluate the exam result
Normal calcitonin reference values may vary depending on the laboratory that performs the test. Normal values are those below 8.4 pg / ml in men and 5 pg / ml in women. After calcium stimulation, those below 30 pg / ml and positive when above 100 pg / ml can be considered normal. Between 30 and 99 pg / dl, the test is considered indeterminate, and further tests must be performed to confirm the disease.
