Circadian and individual variability of TSH and thyroid hormones in subjects with euthyroidism

Cover Page


To ivestigate circadian and individual variability of TSH, fТ4, fТ3 in subjects without evident thyroid dysfunction. 27 persons at the age of 18–60 years have been included. Measurements of serum TSH, fT4, fT3 were performed at 8.00–9.00 and 14.00–16.00 during the day and at 8.00–9.00 in 4–6 weeks. The median of TSH concentrations in the morning was 2.28 mU/l, at the daytime – 1.6 mU/l (р < 0.05). The amplitude of TSH circadian variability reached 58% (Me = 21.45%). According to the current TSH reference ranges (0.4–4.0 mU/l) all participants had an euthyroidism in the morning and at the daytime. According to the proposed TSH reference ranges (0.4–2.5 mU/l) 12 participants (44.4%) in the morning and 4 participants (14.8%) at the daytime have been classified as having a hypothyroidism. TSH levels in 4–6 weeks differed from initial on -42.8–7.71%. Statistically and clinically significant variability of fT4 has not been found. Variability of fТ3 has appeared statistically significant and correlation with TSH changes.

About the authors


  1. Свиридонова М.А., Фадеев В.В., Ильин А.В. Клинические аспекты циркадианной вариабельности уровня ТТГ // Клин. экспер. тиреоидол. №4. 2009. С. 38–41.
  2. Baloch Z., Carayon P., Conte-Devolx B. et al. Guidelines Committee, National Academy of Clinical Biochemistry. Laboratory medicine practice guidelines. Laboratory support for the diagnosis and monitoring of thyroid disease // Thyroid. 2003. V. 13. P. 3–126;
  3. Brabant G., Beck-Peccoz P., Jarzab B. et al. Is there a need to redefine the upper normal limit of TSH? // Eur. J. Endocrinol. 2006. V. 154. P. 633–637.
  4. Gharib H., Tuttle R.M., Baskin H.J., Fish L.H. et al. American Association of Clinical Endocrinologists/American Thyroid Association/Endocrine Society. Subclinical thyroid dysfunction: a joint statement on management from the American Association of Clinical Endocrinologists, the American Thyroid Association, and the Endocrine Society // Endocr. Pract. 2004. V. 10(6). P. 497–501.
  5. Hollowell J.G., Staehling N.W., Flanders W.D. et al. Serum TSH, T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III) // J. Clin. Endocrinol. Metab. 2002. V. 87. P. 489–499.
  6. Maes M., Mommen K., Hendrickx D. et al. Components of biological variation, including seasonality, in blood concentrations of TSH, TT , FT , PRL, cortisol and testosterone in healthy volunteers // Clin. Endocrinol. (Oxf). 1997. V. 46(5). P. 587–598.
  7. Persani L., Terzolo M., Asteria C. et al. Circadian variations of thyrotropin bioactivity in normal subjects and patients with primary hypothyroidism // J. Clin. Endocrinol. Metab. 1995. V. 80. P. 2722–2728.
  8. Russell W., Harrison R.F., Smith N. et al. Free triiodothyronine has a distinct circadian rhythm that is delayed but parallels thyrotropin levels // J. Clin. Endocrin. Metab. 2008. V. 93(6). P. 2300–2306.
  9. Wartofsky L., Dickey R.A. The Evidence for a Narrower Thyrotropin Reference Range Is Compelling // J. Clin. Endocrin. Metab. 2005. V. 90. P. 5483–5488.



Abstract - 831

PDF (Russian) - 811




Copyright (c) 2010 ., ., .

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

This website uses cookies

You consent to our cookies if you continue to use our website.

About Cookies