Measurement of red blood cell zinc concentration with Zn-test kit: Discrimination between hyperthyroid Graves' disease and transient thyrotoxicosis

Noriyo Sayama, Katsumi Yoshida, Kouki Mori, Hiroshi Fukazawa, Hironobu Hori, Naoki Nakazato, Jun Ichi Tani, Yoshinori Nakagawa, Sadayoshi Ito

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21 Citations (Scopus)

Abstract

We have previously reported in patients with hyperthyroidism that the red blood cell (RBC) zinc (Zn) concentration reflects the mean thyroid hormone concentration over the preceding months. In the present study, the concentration of RBC Zn was measured by a simple and easy method with a Zn- test Wako kit. Within-run and between-run precision were 1.4% and 1.3%, respectively. The relationship between RBC concentration and dilution was linear. The average recovery was 103%. A good correlation (r=0.97) was obtained between this method and atomic absorption spectrophotometry. The mean concentration of RBC Zn in 39 euthyroid controls was 12.6 ± 1.3 mg/l, ranging from 10.4 to 15.1 mg/l. The RBC Zn concentrations in 38 patients with Graves' disease, in 10 patients with silent thyroiditis and in 3 patients with gestational thyrotoxicosis were 7.3 ± 1.6 (3.2-9.8), 12.0 ± 1.6 (9.5- 14.2) and 11.8 ± 1.7 (10.5-13.7) mg/l, respectively. The concentration of RBC Zn was able to differentiate hyperthyroid Graves' disease from transient thyrotoxicosis except in 1 case and was a better index than TSH-binding inhibitory immunoglobulin. These results indicate that measuring RBC Zn with the Zinc-test Wako kit is very useful in differentiating hyperthyroid Graves' disease from transient thyrotoxicosis.

Original languageEnglish
Pages (from-to)767-772
Number of pages6
Journalendocrine journal
Volume45
Issue number6
DOIs
Publication statusPublished - 1998 Jan 1

Keywords

  • Gestational thyrotoxicosis
  • Graves' disease
  • Red blood cell
  • Silent thyroiditis
  • Zinc

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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    Sayama, N., Yoshida, K., Mori, K., Fukazawa, H., Hori, H., Nakazato, N., Tani, J. I., Nakagawa, Y., & Ito, S. (1998). Measurement of red blood cell zinc concentration with Zn-test kit: Discrimination between hyperthyroid Graves' disease and transient thyrotoxicosis. endocrine journal, 45(6), 767-772. https://doi.org/10.1507/endocrj.45.767