Calcitonin in the blood
Last reviewed: 23.04.2024
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The reference values (norm) of calcitonin concentration in serum are less than 150 pg / ml (ng / l).
Calcitonin is a peptide hormone consisting of 32 amino acids and produced by cells of parafollicular epithelium (C-cells) of the thyroid gland. The half-life of the hormone is 5-8 minutes. Normally, calcitonin is involved in the regulation of calcium metabolism, being a physiological antagonist of PTH. In osteocytes, it inhibits enzymes that destroy bone tissue, calcitonin causes increased clearance and release of Ca 2+, phosphate, Mg 2+, K +, Na + in the kidney tubules and thereby contributes to a decrease in Ca 2+ concentration in the blood. Synthesis and release of calcitonin regulates the concentration of Ca 2+ in the blood: its increase stimulates the synthesis and secretion of the hormone, and the inhibition inhibits these processes. In addition, secretion of calcitonin stimulates gastrin and glucagon.
In clinical practice, the calcitonin is necessary to diagnose medullary thyroid cancer, since this disease in blood content increases considerably as well as for the complex evaluation of disorders of calcium metabolism (with PTH and vitamin D 3 ).
Determination of calcitonin is of exceptional importance for the diagnosis of medullary thyroid cancer. The increase in basal and stimulated concentration of calcitonin in the serum during the provocative test with pentagastrin is the main diagnostic criterion of medullary thyroid carcinoma, the results of the study correlate with the stage of the disease and the size of the tumor. In 70% of patients the basal concentration of calcitonin is in the range of 500-2000 pg / ml; at 30% - within the limits of norm or slightly exceeds normal parameters. After the administration of pentagastrin, the concentration of calcitonin increases in almost all patients with medullary thyroid cancer. If the basal level is initially increased, then during the test with pentagastrin, its concentration rises in the blood 10-20 times. In cases where the basal level of calcitonin is at the lower limits of the norm or is not determined, and after stimulation with pentagastrin significantly increases, but does not go beyond the limits of the norm, it is necessary to suspect the early stage of medullary cancer or hyperplasia of the thyroid C-cells. In some patients, an infusion of calcium preparations should be used as a stimulant, since tumors may not react to pentagastrin.
A persistent increase in calcitonin in the blood after removal of the tumor in patients with medullary thyroid cancer may indicate a non-surgical operation or the presence of distant metastases. A rapid rise in the level of calcitonin after surgery indicates a relapse of the disease.
An increase in the concentration of calcitonin in the blood is possible with non-malignant lung diseases, acute pancreatitis, hyperparathyroidism, pernicious anemia, Paget's disease. An increase in the concentration of calcitonin is also observed in malignant neoplasms of the mammary gland, stomach (most often with Zollinger-Ellison syndrome), kidneys, liver.
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