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Why would a patient have increasingly higher TSH with more T4 thyroid hormone?

My patient had covid a few months back and her TSH went up... and then it went higher to 40.00 w/ an increase in T4.

Thyroid abnormalities are seen with COVID-19 but more information and further evaluation are needed including the following:

  • Have pituitary abnormalities been ruled out?
  • Have additional thyroid tests including antibodies been carried out?

It is especially important to know how current TSH and T4 compare to past lab values. It is always best to assess as many sets of results as possible in order to identify trends and to use the same lab and lab location.

More information should be evaluated:

With a TSH that high, has an evaluation of pituitary and/or hypothalamic function been carried out? Were free T4 and total, free, and reverse T3 measured as well? Did T4 increase above optimal or above standard?

Have thyroid antibodies been tested? Research suggests that autoimmune thyroiditis can coexist with thyroid hormone resistance in which you’ll see an elevated TSH and an elevated total and free T4 (Gnanapragasam 2021).

It is also important to look at liver/metabolic enzymes as GGT and ALT can increase steadily as TSH rises (Targher 2008).

It’s important to know if your patient’s increased TSH and T4 were trending prior to their COVID-19 infection. The thyroid may be more susceptible to a SARS-COV-2 insult due to its increased activity and expression of ACE2 receptors. Thyroid abnormalities are noted in a significant number of COVID-19 patients though a downward trend was noted for TSH and T4 during acute infection, even in those with a history of hypothyroidism (Malik 2021, Khoo 2021).


Gnanapragasam, Helen Prathiba, Amrutha Idupuganti, and Salman Zahoor Bhat. "Coexistence of Thyroid Hormone Resistance and Autoimmune Thyroid Disease: Not a Mere Coincidence." Journal of the Endocrine Society 5.Supplement_1 (2021): A924-A925. [R]

Khoo, Bernard et al. “Thyroid Function Before, During, and After COVID-19.” The Journal of clinical endocrinology and metabolism vol. 106,2 (2021): e803-e811. doi:10.1210/clinem/dgaa830 [R]

Malik, Jahanzeb et al. “Association of hypothyroidism with acute COVID-19: a systematic review.” Expert review of endocrinology & metabolism vol. 16,5 (2021): 251-257. doi:10.1080/17446651.2021.1968830 [R]

Targher, Giovanni et al. “Association between serum TSH, free T4 and serum liver enzyme activities in a large cohort of unselected outpatients.” Clinical endocrinology vol. 68,3 (2008): 481-4. doi:10.1111/j.1365-2265.2007.03068.x [R]