, Volume 64, Issue 1, pp 118–121 | Cite as

Levothyroxine absorption test results in patients with TSH elevation resistant to treatment

  • Ilgin Yildirim SimsirEmail author
  • Utku Erdem Soyaltin
  • Ahmet Gokhan Ozgen
Original Article



Persistent elevation of thyroid-stimulating hormone (TSH) is common in endocrinology practice in patients undergoing replacement or suppression therapy with levothyroxine sodium (LT4). After examining the causes of this condition, LT4 absorption test is recommended. In this report, we wanted to share our results of LT4 absorption test in patients with elevated TSH levels.


The files of patients who presented to our clinic between 2015 and 2018, whose TSH elevation continued despite high-dose LT4 therapy, and who underwent absorption test were reviewed retrospectively.


Levothyroxine sodium absorption test was applied to five patients. Absorption test revealed LT4 malabsorption in two patients and pseudomalabsorption in the other three patients.


When all published pseudomalabsorption cases were considered, it has been stated that at least 2.5 times increase in basal fT4 level may exclude malabsorption. The formula we used has been implemented by Cleveland Clinic since 2014.


In cases where TSH normalization is not achieved despite high doses of LT4 therapy, LT4 absorption test is an easy test for administration and interpretation and prevents unnecessary medical treatments and examinations.


Levothyroxine Malabsorption Pseudomalabsorption 


Author contributions

I.Y.S. and U.E.S. wrote the manuscript. I.Y.S. and A.G.O. reviewed/edited the manuscript.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethics statement

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.


  1. 1.
    J. Jonklaas, A.C. Bianco, A.J. Bauer, K.D. Burman, A.R. Cappola, F.S. Celi, D.S. Cooper, B.W. Kim, R.P. Peeters, M.S. Rosenthal, A.M. Sawka, Guidelines for the treatment of hypothyroidism: prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement. Thyroid 24(12), 1670–1751 (2014). CrossRefGoogle Scholar
  2. 2.
    S.K. Grebe, R.R. Cooke, H.C. Ford et al. Treatment of hypothyroidism with once weekly thyroxine. J. Clin. Endocrinol. Metab. 82(3), 870–875 (1997)Google Scholar
  3. 3.
    Y. Kashiwagura, S. Uchida, S. Tanaka et al. Clinical efficacy and pharmacokinetics of levothyroxine suppository in patients with hypothyroidism. Biol. Pharm. Bull. 37(4), 666–670 (2014)CrossRefGoogle Scholar
  4. 4.
    C. Cappelli, I. Pirola, L. Daffini et al. A double-blind placebo-controlled trial of liquid thyroxine ingested at breakfast: results of the TICO Study. Thyroid 26(2), 197–202 (2016). CrossRefGoogle Scholar
  5. 5.
    D. Brancato, A. Scorsone, G. Saura et al. Comparison of TSH levels with liquid formulation versus tablet formulations of levothyroxine in the treatment of adult hypothyroidism. Endocr. Pract. 20(7), 657–662 (2014). CrossRefGoogle Scholar
  6. 6.
    L. Anderson, F. Joseph, N. Goenka, V. Patel, Isolated thyroxine malabsorption treated with intramuscular thyroxine injections. Am. J. Med. Sci. 337(2), 150–152 (2009). CrossRefGoogle Scholar
  7. 7.
    M.T. Hays, Parenteral thyroxine administration. Thyroid 17(2), 127–129 (2007)CrossRefGoogle Scholar
  8. 8.
    C. Virili, A. Antonelli, M.G. Santaguida, S. Benvenga, M. Centanni, Gastrointestinel malabsorption of thyroxine. Endocr. Rev. (2018).
  9. 9.
    E. Lahner, C. Virili, M.G. Santaguida, B. Annibale, M. Centanni, Helicobacter pylori infection and drugs malabsorption. World J. Gastroenterol. 20(30), 10331–10337 (2014). CrossRefGoogle Scholar
  10. 10.
    M. Cellini, M.G. Santaguida, C. Virili, S. Capriello, N. Brusca, L. Gargano, M.Centanni, Hashimoto’s thyroiditis and autoimmune gastritis. Front Endocrinol. (Lausanne). 8, 92 (2017). CrossRefGoogle Scholar
  11. 11.
    M. Ruchala, E. Szczepanek-Parulska, A. Zybek, The influence of lactose intolerance and other gastro-intestinal tract disorders on L-thyroxine absorption. Endokrynol. Pol. 63(4), 318–323 (2012)Google Scholar
  12. 12.
    G.E. Sun, K.M. Pantalone, C. Faiman, M. Gupta, L. Olansky, B. Hatipoglu, The clinical utility of free thyroxine in oral levothyroxine absorption testing. Endocr. Pract. 20(9), 925–929 (2014)CrossRefGoogle Scholar
  13. 13.
    G.M. Rdzak, L.M. Whitman, S.E. Inzucchi, Levothyroxine pseudo-malabsorption: testing and treatment in the outpatient setting. Ther. Adv. Endocrinol. Metab. 9(7), 217–222 (2018). CrossRefGoogle Scholar
  14. 14.
    E. Livadariu, H. Valdes-Socin, M.C. Burlacu, C. Vulpoi, A.F. Daly, A. Beckers, Pseudomalabsorption of the thyroid hormones: case report and review of the literatüre. Ann. Endocrinol. (Paris) 68(6), 460–463 (2007)CrossRefGoogle Scholar
  15. 15.
    M.T. Hays, Thyroid hormone and the gut. Endocr. Res. 14(2-3), 203–224 (1988)CrossRefGoogle Scholar
  16. 16.
    M.T. Hays, Localization of human thyroxine absorption. Thyroid 1(3), 241–248 (1991)CrossRefGoogle Scholar
  17. 17.
    K.B. Ain, S. Refetoff, H.G. Fein, B.D. Weintraub, Pseudomalabsorption of levothyroxine. JAMA 266(15), 2118–2120 (1991)CrossRefGoogle Scholar
  18. 18.
    D.J. Lips, M.T. van Reisen, V. Voigt, W. Venekamp, Diagnosis and treatment of levothyroxine pseudomalabsorption. Neth. J. Med. 62(4), 114–118 (2004)Google Scholar
  19. 19.
    R.G. Symons, L.J. Murphy, Acute changes in thyroid function tests following ingestion of thyroxine. Clin. Endocrinol. (Oxf.). 19(4), 539–546 (1983)CrossRefGoogle Scholar
  20. 20.
    R.M.V. Soares, R.M. de Figueiredo, M.M.N. Dantas et al. Rapid levothyroxine (Lt4) absorption test for diagnosis of Lt4 pseudomalabsorption: case report and proposal of a cutoff point. J. Endocrinol. Diabetes Obes. 4(1), 1083 (2016)Google Scholar

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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Division of Endocrinology and Metabolism DisordersEge University Medical FacultyIzmirTurkey

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