Calcitonin - plasma or serum

Last updated: Friday, 19, March, 2004

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Item Process
Specimen

5 mL blood in lithium heparin or plain tube.

Method

Immunoassay.

Reference Interval

<15 pmol/L.

Application

Diagnosis of medullary carcinoma of the thyroid, including investigation of asymptomatic family members at risk for multiple endocrine neoplasia 2 (when an underlying mutation has not been identified).

Follow-up of patients with medullary carcinoma after surgery.

Interpretation

Elevated in medullary carcinoma of the thyroid, levels may be increased prior to clinical evidence of a lump.

In doubtful cases a pentagastrin stimulation test is done, pentagastrin 0.5 µg/kg is given intravenously.

Levels increase in medullary carcinoma of the thyroid but remain unchanged in normals.

Molecular genetics, testing for mutation in the ret oncogene, is more reliable for identification of MEN type 2 syndromes.

Reference

Cohen R et al. Ann Med Interne 2003; 154(2): 109-116.