This Article Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by AMINO, N. Articles by MIYAI, K. Search for Related Content PubMed PubMed Citation Articles by AMINO, N. Articles by MIYAI, K.

Serum Ratio of Triiodothyronine to Thyroxine, and Thyroxine-Binding Globulin and Calcitonin Concentrations in Graves' Disease and Destruction- Induced Thyrotoxicosis^*

The Central Laboratory for Clinical Investigation and The Department of Laboratory Medicine, Osaka University Hospital Osaka, Japan
The Department of Medicine and Geriatrics, Osaka University Hospital Osaka, Japan

Address requests for reprints to: Dr. N. Amino, The Central Laboratory for Clinical Investigation, Osaka University Hospital, 1-1-50 Fukushima, Fukushima-ku, Osaka 553, Japan.

The serum ratios of T³ to T⁴, and T⁴-binding globulin (TBG) and calcitonin concentrations were studied in cases of thyrotoxic Graves' disease and destruction-induced thyrotoxicosis. In 272 patients with Graves' disease, 209 of 240 (87÷) untreated patients without complications had high T³ to T⁴ ratios (nanograms per ·g) of more than 20. Six of 32 (19÷) patients with Graves' disease who had complications (15 with pregnancy, 14 with increased TBG, and 3 with conditions associated with a low T³ syndrome) had high T³ to T⁴ ratios. Eleven of 74 (15÷) patients with destruction-induced thyrotoxicosis (24 with subacute thyroiditis, 39 with postpartum transient thyrotoxicosis, and 11 with spontaneous transient thyrotoxicosis) had high Ta to T⁴ ratios. Patients who had serum T⁴ levels of more than 30 ·g/dl and/or T³ levels of more than 800 ng/dl had Graves' disease. There was no significant correlation between the T³ to T⁴ ratio and activities of thyroid-stimulating immunoglobulins in thyrotoxic patients with Graves' disease who had no complications.

The average serum levels of TBG in destruction-induced thyrotoxicosis and thyrotoxic Graves' disease were 20.7 ± 4.3 ·g/ ml (mean ± SD; n = 22), and 19.9 ± 4.0 (n = 41), respectively, which were significantly lower than that in healthy subjects (22.7 ± 4.4 ·g/ml; n = 165), but there was no difference between the values in the two groups of thyrotoxicosis patients. The average serum level of calcitonin in destruction-induced thyrotoxicosis patients was 96.7 ± 66.7 pg/ml (n = 21), which was significantly (P < 0.05) higher than the values in patients with thyrotroxic Graves' disease (62.0 ± 44.7 pg/ml; n = 26) and in healthy subjects (63.9 ± 31.2 pg/ml; n = 29), but the difference in values in the two groups of thyrotoxicosis was not clinically useful because of considerable overlap of individual values. The T³ to T⁴ ratio is a simple and helpful index for the differentiation of the two types of thyrotoxicosis. A T³ to T⁴ ratio less than 20 in thyrotoxic patients before therapy is a laboratory signal of destruction-induced thyrotoxicosis or Graves' disease with complications, but final differentiation should be confirmed by measuring radioactive iodine uptake.

^* This work was supported in part by a research grant from the Intractable Disease Division, Public Health Bureau, Ministry of Health and Welfare, Japan.

Received November 21, 1980.

This article has been cited by other articles:

				P. Laurberg, H. Vestergaard, S. Nielsen, S. E. Christensen, T. Seefeldt, K. Helleberg, and K. M. Pedersen Sources of Circulating 3,5,3'-Triiodothyronine in Hyperthyroidism Estimated after Blocking of Type 1 and Type 2 Iodothyronine Deiodinases J. Clin. Endocrinol. Metab., June 1, 2007; 92(6): 2149 - 2156. [Abstract] [Full Text] [PDF]

				E. N. Pearce, A. P. Farwell, and L. E. Braverman Thyroiditis N. Engl. J. Med., June 26, 2003; 348(26): 2646 - 2655. [Full Text] [PDF]

				G. H. Daniels Amiodarone-Induced Thyrotoxicosis J. Clin. Endocrinol. Metab., January 1, 2001; 86(1): 3 - 8. [Full Text]

				D. Glinoer The Regulation of Thyroid Function in Pregnancy: Pathways of Endocrine Adaptation from Physiology to Pathology Endocr. Rev., June 1, 1997; 18(3): 404 - 433. [Abstract] [Full Text]

				S. N. Levine Current Concepts of Thyroiditis Arch Intern Med, October 1, 1983; 143(10): 1952 - 1956. [Abstract] [PDF]