A 36-year-old man had a serum parathyroid hormone (PTH)4 concentration of 1847 pg/mL. He had normal kidney function, normal calcium, phosphorus, magnesium and vitamin D concentrations, and no symptoms of hyperparathyroidism. One year earlier his PTH concentration was 38 pg/mL (reference interval 15-65 pg/mL). The patient had a familial form of multiple endocrine neoplasia (MEN) type 2A.
1. What are the most common causes of increased plasma PTH concentrations?
2. Is there a potential preanalytical cause for this increased PTH concentration?
The answers are below.
Increased PTH concentration is associated with primary hyperparathyroidism (1) (associated with increased calcium), secondary hyperparathyroidism, 25-OH-vitamin-D deficiency, magnesium deficiency, or chronic kidney failure (associated with decreased calcium).
To prevent hypoparathyroidism (2) following surgical treatment, parathyroid autotransplantation to the forearm is often performed (3, 4). Because this patient had no biochemical or clinical signs of hyperparathyroidism but had a history of MEN2A, suspicion for local production of PTH was raised (autotransplantation). We confirmed this hypothesis by measuring PTH in both forearms: left, 944.9 pg/mL; right, 27.0 pg/mL. He was unaware that he had undergone autotransplantation after parathyroidectomy as a 6-year-old child.
Author Contributions: All authors confirmed they have contributed to the intellectual content of this paper and have met the following 3 requirements: (a) significant contributions to the conception and design, acquisition of data, or analysis and interpretation of data; (b) drafting or revising the article for intellectual content; and (c) final approval of the published article.
Authors' Disclosures or Potential Conflicts of Interest: No authors declared any potential conflicts of interest.
Acknowledgments: The authors are grateful to Drs. J. Tounsi, N. Lievre, and F. Mingaud for having referred this patient's case to them.
(1.) Wilhelm SM, Wang TS, Ruan DT, Lee JA, Asa SL, Duh QY, et al. The American Association of Endocrine Surgeons guidelines for definitive management of primary hyperparathyroidism. JAMA Surg. 2016;151:959-68.
(2.) Moffet J, Suliburk J. Parathyroid autotransplantation. Endocr Pract. 2011; 17 (Suppl 1):83-9.
(3.) Carling T, Udelsman R. Parathyroid surgery in familial hyperparathyroid disorders. J Intern Med 2005; 257:27-37.
(4.) Cohen MS, Dilley WG, Wells SA Jr., Moley JF, Doherty GM, Sicard GA, et al. Long-term functionality of cryopreserved parathyroid autografts: a 13-year prospective analysis. Surgery 2005;138:1033-40.
 Departments of  Biology,  Endocrinology, and  Radiology, University Hospital of Nantes, France.
* Address correspondence to this author at: 9, quai Moncousu Nantes Cedex 1, France. Fax 33-240083991; e-mail email@example.com.
Received August 16,2016; accepted September 23,2016.
 Nonstandard abbreviations: PTH, parathyroid hormone; MEN, multiple endocrine neoplasia.
A.S. Outtier,  M. Le Bras,  F. Lerat,  D. Masson,  and K. Bach-Ngohou  *
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|Title Annotation:||the Clinical Chemist: What Is Your Guess?|
|Author:||Outtier, A.S.; Bras, M. Le; Lerat, F.; Masson, D.; Bach-Ngohou, K.|
|Article Type:||Clinical report|
|Date:||Feb 1, 2017|
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