Hormonal assay is useful in the diagnosis of medullary thyroid cancer.
Thyrocalcitonin is a 32 amino acid peptide synthesized by the thyroid parafollicular C cells.
The rate is dependent on blood levels of ionized calcium, phosphate, magnesium and some hormones gastrin, glucagon, estrogens, histamine.
It regulates the mineral metabolism by inhibiting bone resorption and increasing calcium excretion.
Strict fasting for 12 hours is required.
The blood sample is centrifuged and refrigerated.
The assay is radioimmunoassay or enzyme immunoassay.
Normal values: rate below 200 ng / L.
The rate may be increased non-specifically in pathologies such renal failure, hyperparathyroidism or pregnancy.
There is also a rise in rates in case of thyroid cancer, especially in cases of medullary cancer nodule cold scintigraphic (reliable marker).
The interest of the review also lies in the monitoring of cancer, postoperative: after total thyroidectomy extended, the rate must drop immediately (the half-life is short indeed); a new increase in the rate is a sign of recurrence.
Apart from a thyroid damage, high levels may be observed in case of colic tumors, lung and breast. But also in liver cirrhosis and liver cancer.
The absence of fasting increases the blood level of thyrocalcitonine, without being pathological provided.