Spurious hypercalcitoninemia in patients with nodular thyroid disease induced by heterophilic antibodies

✍ Scribed by Jung Min Kim; Ki-Wook Chung; Seok Won Kim; Seon Hyeong Choi; Hye Sook Min; Ji-na Kim; Woo-jae Won; Seok Ki Kim; Ji In Lee; Jae Hoon Chung; Sun Wook Kim

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 141 KB
• Volume: 32
• Category: Article
• ISSN: 1043-3074
• DOI: 10.1002/hed.21145

✦ Synopsis

Abstract

Background

Serum calcitonin is the most useful tumor marker for the diagnosis and follow‐up of medullary thyroid carcinoma (MTC). Spurious hypercalcitoninemia caused by heterophilic antibody interference (HAI) is rarely found in patients without MTC.

Methods

We studied 2 patients with hypercalcitoninemia and thyroid nodules, but no evidence of MTC on fine‐needle aspiration cytology. We performed calcium stimulation tests, measured serum calcitonin with another calcitonin kit, performed dilution tests, and remeasured serum calcitonin after applying heterophilic blocking tubes.

Results

In a 31‐year‐old woman with no response to the calcium stimulation test, serum calcitonin was <5 pg/mL using another kit. After we applied heterophilic blocking tubes, the serum calcitonin level decreased to normal range. We concluded that patient had spurious hypercalcitoninemia. In a 63‐year‐old woman, all tests revealed that the patient had true hypercalcitoninemia. The patient underwent total thyroidectomy that revealed MTC.

Conclusions

We suggest that patients suspected for spurious hypercalcitoninemia should undergo further investigation due to HAI. © 2009 Wiley Periodicals, Inc. Head Neck, 2010