Examinations
Examinations
Calcitonin is a hormone involved in calcium metabolism regulation. It serves as a tumor marker for medullary thyroid cancer (MTC) in oncology. Calcitonin is primarily synthesized by parafollicular C-cells of the thyroid gland.
Calcitonin Receptors and Functions
Calcitonin receptors are found in:
- Osteoclasts
- Kidneys
- Monocytes
- Brain
- Placenta
- Lungs
- Liver
- Reproductive organs
Its hypocalcemic effect is achieved through:
- Inhibiting osteoclast activity, reducing bone resorption
- Decreasing calcium reabsorption in the kidneys
- Reducing calcium absorption in the intestines
- Lowering phosphate levels in the blood by decreasing phosphate reabsorption in the kidneys
Although calcitonin functions as a physiological antagonist of parathyroid hormone (PTH), its role in calcium-phosphorus metabolism is less significant than that of PTH.
- The test is performed on a venous blood sample.
- Fasting (8–14 hours) is required before the test.
- Psychological and physical stress should be avoided before the test.
- Alcohol consumption is not allowed before the test.
- The patient should rest for 20–30 minutes before the blood draw.
- Diagnosis of medullary thyroid cancer
- Assessing the effectiveness of surgical treatment and post-surgery monitoring
- Screening family members of patients with medullary thyroid cancer
Causes of Increased Calcitonin Levels
- Medullary thyroid cancer
- Leukemia
- C-cell hyperplasia
- Zollinger-Ellison syndrome
- Chronic kidney disease
- Uremia
- Carcinoid syndrome
- Alcoholic liver cirrhosis
- Pancreatitis
- Benign lung tumors
- Chronic inflammatory diseases
- Pregnancy
- Pheochromocytoma
- Thyroiditis
Causes of Decreased Calcitonin Levels (During Monitoring)
- Following physical exertion