Calcitonin (Thyrocalcitonin)
Also known as: Thyrocalcitonin
Use
Detection and confirmation C-cell hyperplasia (the precursor of medullary carcinoma of thyroid) as well as a tumor marker for diagnosis and management of medullary carcinoma of the thyroid gland. Preoperative serum calcitonin is reported to roughly correlate with tumor weight or extent of disease; therefore, postoperative levels also have prognostic application. The doubling time of serum levels correlates with a recurrence.1 Multiple endocrine neoplasia (MEN) type II includes medullary carcinoma of the thyroid, hyperparathyroidism, and pheochromocytoma (Sipple syndrome). MEN type IIB includes medullary carcinoma of the thyroid, pheochromocytoma, mucosal neuromas, marfanoid habitus, and intestinal ganglioneuromatosis.2 An important use of calcitonin assay is in follow-up of patients with medullary carcinoma and work-up of their families to detect early, subclinical cases. Indications for calcitonin assay include family history of unspecified type of thyroid cancer, calcified thyroid mass, thyroid tumor associated with hypercalcemia and/or pheochromocytoma, amyloid-containing metastatic carcinoma with unknown primary site and the presence of mucosal neuromas.3
Special Instructions
When requesting this test, state on the request form if calcium infusion or pentagastrin injection tests are part of the patient's preparation. It is recommended to use only one assay method consistently to monitor each patient's therapy. This procedure is intended for one-time use only. For serial monitoring, use the serial monitoring number 480103.
Limitations
In individuals with medullary carcinoma of the thyroid, the baseline calcitonin may be normal, particularly in familial cases. Microscopic medullary carcinoma or C-cell hyperplasia often presents with normal basal calcitonin levels, necessitating provocative testing with calcium or pentagastrin. The test is not suitable as a screening tool. Hemolysis can cause falsely elevated results, and the assay may not uniformly react with all calcitonin forms. Patients with high calcitonin levels may experience secretory diarrhea, and various other conditions can cause increased levels.
Methodology
Immunoassay (CLIA)
Biomarkers
LOINC Codes
- 1992-7
- 1992-7
Result Turnaround Time
3-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.4 mL
Container
Red-top tube or gel-barrier tube
Collection Instructions
Separate serum from cells. Transfer the serum into a LabCorp PP transpak frozen purple tube with screw cap (LabCorp N° 49482). Freeze immediately and maintain frozen until tested.
Patient Preparation
Patient should be fasting.
Storage Instructions
Freeze.
Causes for Rejection
Gross hemolysis; specimen not received frozen; lipemia; plasma specimen
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unstable |
| Refrigerated | Unstable |
| Frozen | 90 days |