Calcitonin

Keywords: Pentagastrin stimulation test

Specimen:

5 mL blood in lithium heparin or plain tube.

Method:

Immunoassay.

Reference Interval:

Assay dependent.

Females: < 5 ng/L

Males: < 12 ng/L

0 - 6 months: < 40 ng/L

6 months - 3yrs: < 15 ng/L

Over 3 years, values similar to adults.

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 Intern 2003; 154: 109-116.

Basuyau JP et al. Clin Chem 2004; 50: 1828-1830.