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Thyroid Diseases

Can Prednisone Affect TSH Test Results?



I have asthma. I am taking Prednisone in addition to Ketek for an upper respiratory infection. I am scheduled to have an initial TSH test to see if my thyroid is underactive. Can Prednisone affect or alter the TSH test results? If so, how long should I wait after stopping Prednisone to take the test to get a more accurate measurement? Thank you for your time.


You have not mentioned how long you have been taking prednisone and how long you will be taking it. As you pointed out, glucocorticoids, such as prednison decrease thyroid stimulating hormone (TSH) secretion and lower serum TSH concentrations, although long term glucocorticoid therapy does not result in sustained abnormality in TSH secretion, nor does cause hypothyroidism.

Therefore, if you are taking prednisone for a short period of time (less than 2-3 weeks), you can wait for about 6-8 weeks to have your thyroid tested or your thyroid status can be evaluated at any time based on your free thyroid hormone level instead of TSH. If you are taking prednisone for more than few months, on the other hand, you can have your thyroid function tested at any time since long-term glucocorticoids does not result in sustained TSH secretion abnormalities.

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Response by:

Marzieh  Salehi, MD Marzieh Salehi, MD
Assistant Professor of Endocrinology
College of Medicine
University of Cincinnati