Serum calcitonin is used in the diagnosis and monitoring of medullary thyroid cancer as well as in the evaluation of type II multiple endocrine neoplasia and familial medullary thyroid cancer.
Calcitonin (CT), is a polypeptide hormone secreted by thyroid C cells and involved in the regulation of calcium and phosphorus levels in the blood. When high levels of calcium (hypercalcemia) are present in the blood, calcitonin is excreted. This results in the inhibition of calcium absorption by the gastrointestinal tract, the inhibition of calcium absorption by the bones (by osteoclasts and osteocytes), and increased renal calcium excretion. These actions are antagonistic to the parathyroid hormone and lead to a decrease in blood calcium levels.
The calcitonin measurement is mainly used for the evaluation of medullary thyroid carcinoma (MTC), which is characterized by calcitonin over-secretion with the concomitant presence of normal serum calcium levels. In some patients with medullary thyroid cancer, calcitonin levels may be normal. After surgery, calcitonin levels should be monitored periodically to ensure they return to normal. If levels remain elevated, then it is likely that there is a tissue that is producing calcitonin. If levels drop after surgery and then increase, there is a chance cancer will recur. Family members of patients with medullary thyroid cancer should be regularly monitored using calcitonin measurement.
Possible Interpretations of Pathological Values
- Increase: Alcoholic cirrhosis, breast cancer, C-cell hyperplasia, chronic kidney failure, Cushing's disease, ectopic calcitonin production (such as in pancreatic cancer), hypercalcemia, pancreatic islet tumors, lung cancer (small cell), myeloid thyroid cancer, parathyroid adenoma, parathyroid hyperplasia, malignant anemia, pheochromocytoma, thyroiditis, uremia, Zollinger-Ellison syndrome. Medications: Calcium, epinephrine, glucagon, oral contraceptives, pentagastrin.
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.