Chemistry
Thyroid related
Calcitonin

Author: Nat Pernick, M.D. (see Authors page)

Revised: 23 February 2016, last major update March 2011

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Calcitonin [title] thyroid
Cite this page: Calcitonin. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/chemistrycalcitonin.html. Accessed December 8th, 2016.
Definition / General
  • Also known as thyrocalcitonin
Pathophysiology
  • Preprocalcitonin (141 amino acids) is produced by parafollicular C cells of thyroid gland
  • Peptide cleavage leads to procalcitonin (116 amino acids), which contains immature calcitonin (33 amino acids)
  • Peptidylglycine-amidating mono-oxidase enzyme produces mature calcitonin (32 amino acids)
  • Function:
    • Calcitonin inhibits osteoclasts from resorbing bone, leading to decreased serum calcium (antagonized by parathyroid hormone)
    • Levels are controlled by serum calcium
Diagrams / Tables

Images hosted on Other servers:

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Calcitonin production

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Calcitonin and parathyroid hormone

Laboratory
Methodology

Indications
  • Medullary thyroid carcinoma-to detect residual tissue or metastases after thyroidectomy (get baseline prior to surgery and also measure 6 months post surgery
  • May help monitor other neuroendocrine carcinomas that produce calcitonin

Limitations
  • Medullary thyroid carcinoma is rarely calcitonin negative (World J Surg Oncol 2006;4:97)
  • High levels in newborns should be repeated several weeks later to see if they drop
  • Run pentagastrin stimulation test if calcitonin value > 10 ng/L but not clearly diagnostic

Reference ranges
  • Adults: < 10 ng/L (pg/ml) indicates no medullary thyroid carcinoma
  • Suggested reference ranges for Advantage ® system: (Clin Chem 2004;50:1828)
    • Children less than 6 months:
      • < 40 ng/L
    • 6 months to 3 years:
      • < 15 ng/L
    • Older children same as adults
  • Adult women: < 5 ng/L
  • Adult men: < 12 ng/L

High values
  • Medullary thyroid carcinoma (> 100 ng/L), C cell pathology (in MEN2 patients), neuroendocrine tumors, hypergastrinemia, hypercalcemia
Additional References