Clotted blood tube (Serum gel separator clot activator tube) (in ice bath)

Minimum blood volume: 5 mL

Paediatric clotted blood tube (in ice bath)

Number of vials: 2

Minimum blood volume: 1.6 mL

Send in ice bath and transport to laboratory immediately.

Fasting morning specimen is preferred to establish baseline values.

Label the time of collection relative to calcium or pentagastrin infusion if the samples are being collected as part of a provocative test.

(See calcium / pentagastrin test for calcitonin.)

Male: < 8.4 ng/L

Female: < 5.0 ng/L

(Source: from manufacturer's kit insert)

Diagnosis of medullary carcinoma of 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 of thyroid after surgery.

Elevated in medullary carcinoma of 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.  Level of calcitonin increases in medullary carcinoma of thyroid but remain unchanged in normal. Molecular genetics, testing for mutation in the ret oncogene, is more reliable for identification of MEN type 2 syndromes.