Thyroid stimulating hormone (TSH), plays an important role in thyroid function and consequently metabolic function. It is the most common lab measurement ordered to determine thyroid function (and with low thyroid function, where would you get the energy to make dinner for your sweetheart?).
One of my learning goals was to look at diagnostic tests and their role in medication management. Originally I was thinking of diagnostic imaging however the diagnostic value of TSH measurements in acutely ill patients has resurfaced time and time again during my clinical re-orientation. This was especially true in patients previously diagnosed with hypothyroidism.
On your floor, a patient with previously controlled hypothyroidism was admitted through the ER where a TSH was ordered. The TSH is low however there are no signs or symptoms of clinical hyperthyroidism…at least none that cannot be explained by another mechanism. Do we dose adjust the levothyroxine?
Now, I do not claim to have all the answers to this question but it was helpful for me to create a short write-up and to create a table of how I would approach TSH (and FT4 if available) measurement with what I now know today. This includes patients believed to be euthyroid prior to admission. I would love feedback from others to know how you approach this.