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Lee, Kim, Hahm, Jung, Kim, Kim, Chung, Choi, and Jung: Differential Diagnostic Value of Total T3/Free T4 Ratio in Graves' Disease and Painless Thyroiditis Presenting Thyrotoxicosis
Original Article
Endocrinology and Metabolism

Endocrinology and Metabolism 2012; 27(2): 121-125.

Published online: 20 June 2012

DOI: https://doi.org/10.3803/EnM.2012.27.2.121

Differential Diagnostic Value of Total T3/Free T4 Ratio in Graves' Disease and Painless Thyroiditis Presenting Thyrotoxicosis

Sang Min Lee1, Soo Kyoung Kim1, Jong Ryeal Hahm1, 2, Jung Hwa Jung1, 2, Ho-Su Kim1, Sungsu Kim1, Soon Il Chung1, 2, Bong Hoi Choi3, Tae Sik Jung1, 2

1Department of Internal Medicine, Gyeongsang National University School of Medicine, Jinju, Korea.

2Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea.

3Department of Nuclear Medicine, Inje University Haeundae Paik Hospital, Busan, Korea.

Corresponding author: Tae Sik Jung. Department of Internal Medicine, Gyeongsang National University School of Medicine, 79 Gangnam-ro, Jinju 660-702, Korea. Tel: +82-55-750-8470, Fax: +82-55-758-9122, taesikjung@gmail.com

Received 28 November 2011       Accepted 21 February 2012

Copyright © 2012 Korean Endocrine Society

(open-access):

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background

It is important to differentiate Graves' disease from that of painless thyroiditis in patients with thyrotoxicosis. In this study, we evaluated the usefulness of total T3 to free T4 ratio in making a differential diagnosis between Graves' disease and painless thyroiditis.

Methods

We reviewed medical records of thyrotoxic patients, who had been diagnosed with Graves' disease or painless thyroiditis, from October 2009 to July 2011. We assessed clinical characteristics, serum levels of total T3, free T4, thyroid stimulating hormone, thyrotropin-binding inhibitory immunoglobulin, and findings of 99mTechnetium thyroid scan. We analyzed the total T3/free T4 ratios between Graves' disease and painless thyroiditis patients.

Results

A total of 76 untreated thyrotoxic patients "49 Graves' disease and 27 painless thyroiditis" were examined. The total T3, free T4 levels and the total T3/free T4 ratios were significantly higher in patients with Graves' disease than in those with painless thyroiditis (P < 0.001). In the total T3/free T4 ratio > 73, the possibility of Graves' disease was significantly higher than in painless thyroiditis (sensitivity, 75.5%; specificity, 70.3%). The sensitivity and specificity of the total T3/free T4 ratio in patients with free T4 < 3.6 ng/dL have been increased (sensitivity, 100%; specificity, 71.4%).

Conclusion

The total T3/free T4 ratios was useful for making a differential diagnosis between Graves' disease and painless thyroiditis.

Keywords: Graves' disease, Painless thyroiditis, Thyrotoxicosis, Total T3/free T4 ratio

Figures and Tables

Fig. 1
Individual serum total T3/free T4 ratios in Graves' disease and painless thyroiditis. Total T3/free T4 ratio in patients with Graves' disease was significantly (P < 0.001) higher than that in patients with painless thyroiditis.
enm-27-121-g001
Fig. 2
Relationship between total T3/free T4 ratio and free T4 value in patients with Graves' disease and painless thyroiditis. Upper-left areas above the line represent the total T3/free T4 ratio of > 73. The ratios in the Graves' disease groups increased as the free T4 values decreased.
enm-27-121-g002
Fig. 3
Individual serum total T3/free T4 ratios of free T4 < 3.6 ng/dL group and free T4 > 3.6 ng/dL group with Graves' disease and painless thyroiditis. The total T3/free T4 ratios were significantly higher in free T4 < 3.6 ng/dL group with Graves' disease. Upper areas above the line represent the total T3/free T4 ratio of > 73.
enm-27-121-g003
Table 1
Baseline characterisitics in patients with Graves' disease and painless thryoiditis
enm-27-121-i001

Values are expressed as mean ± SD. A P value < 0.05 was considered significant.

Table 2
Differential cut-off points of Graves' disease from painless thyroiditis
enm-27-121-i002

AUC, area under the curves.

Table 3
Differentiation of Graves' disease from painless thyroiditis according to the free T4 levels
enm-27-121-i003

AUC, area under the curves; GD, Graves' disease; PT, painless thyroiditis.

References

1. Nikolai TF, Brosseau J, Kettrick MA, Roberts R, Beltaos E. Lymphocytic thyroiditis with spontaneously resolving hyperthyroidism (silent thyroiditis). Arch Intern Med. 1980. 140:478–482.
2. Schorr AB, Miller JL, Shtasel P, Rose LI. Low incidence of painless thyroiditis in the Philadelphia area. Clin Nucl Med. 1986. 11:379–380.
3. Vitug AC, Goldman JM. Silent (painless) thyroiditis. Evidence of a geographic variation in frequency. Arch Intern Med. 1985. 145:473–475.
4. Cooper DS. Braverman LR, Utiger RD, editors. Treatment of thyrotoxicosis. Werner and Ingbar's the Thyroid: A Fundamental and Clinical Text. 2004. 9th ed. Philadelphia: JB Lippincott Co.;665–694.
5. Costagliola S, Morgenthaler NG, Hoermann R, Badenhoop K, Struck J, Freitag D, Poertl S, Weglöhner W, Hollidt JM, Quadbeck B, Dumont JE, Schumm-Draeger PM, Bergmann A, Mann K, Vassart G, Usadel KH. Second generation assay for thyrotropin receptor antibodies has superior diagnostic sensitivity for Graves' disease. J Clin Endocrinol Metab. 1999. 84:90–97.
6. Sayama N, Yoshida K, Mori K, Fukazawa H, Hori H, Nakazato N, Tani J, Nakagawa Y, Ito S. Measurement of red blood cell zinc concentration with Zn-test kit: discrimination between hyperthyroid Graves' disease and transient thyrotoxicosis. Endocr J. 1998. 45:767–772.
7. Schott M, Feldkamp J, Bathan C, Fritzen R, Scherbaum WA, Seissler J. Detecting TSH-receptor antibodies with the recombinant TBII assay: technical and clinical evaluation. Horm Metab Res. 2000. 32:429–435.
8. Vos XG, Smit N, Endert E, Tijssen JG, Wiersinga WM. Frequency and characteristics of TBII-seronegative patients in a population with untreated Graves' hyperthyroidism: a prospective study. Clin Endocrinol (Oxf). 2008. 69:311–317.
9. Morita T, Tamai H, Oshima A, Mukuta T, Fukata S, Kuma K, Kumagai LF, Nagataki S. The occurrence of thyrotropin binding-inhibiting immunoglobulins and thyroid-stimulating antibodies in patients with silent thyroiditis. J Clin Endocrinol Metab. 1990. 71:1051–1055.
10. Amino N, Yabu Y, Miki T, Morimoto S, Kumahara Y, Mori H, Iwatani Y, Nishi K, Nakatani K, Miyai K. Serum ratio of triiodothyronine to thyroxine, and thyroxine-binding globulin and calcitonin concentrations in Graves' disease and destruction-induced thyrotoxicosis. J Clin Endocrinol Metab. 1981. 53:113–116.
11. Shigemasa C, Abe K, Taniguchi S, Mitani Y, Ueda Y, Adachi T, Urabe K, Tanaka T, Yoshida A, Mashiba H. Lower serum free thyroxine (T4) levels in painless thyroiditis compared with Graves' disease despite similar serum total T4 levels. J Clin Endocrinol Metab. 1987. 65:359–363.
12. Izumi Y, Hidaka Y, Tada H, Takano T, Kashiwai T, Tatsumi KI, Ichihara K, Amino N. Simple and practical parameters for differentiation between destruction-induced thyrotoxicosis and Graves' thyrotoxicosis. Clin Endocrinol (Oxf). 2002. 57:51–58.
13. Yanagisawa T, Sato K, Kato Y, Shimizu S, Takano K. Rapid differential diagnosis of Graves' disease and painless thyroiditis using total T3/T4 ratio, TSH, and total alkaline phosphatase activity. Endocr J. 2005. 52:29–36.
14. Yoshimura Noh J, Momotani N, Fukada S, Ito K, Miyauchi A, Amino N. Ratio of serum free triiodothyronine to free thyroxine in Graves' hyperthyroidism and thyrotoxicosis caused by painless thyroiditis. Endocr J. 2005. 52:537–542.
15. Ota H, Amino N, Morita S, Kobayashi K, Kubota S, Fukata S, Kamiyama N, Miyauchi A. Quantitative measurement of thyroid blood flow for differentiation of painless thyroiditis from Graves' disease. Clin Endocrinol (Oxf). 2007. 67:41–45.
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