Hi,

I wanted a second opinion regarding a thyroid blood test. Both my t3 and t4 counts were low (out of range) in my blood test, but my TSH was within range (though a little low within the acceptable range). My general practitioner said the only count that mattered was the TSH, as t3 and t4 can vary too much over the course of the day. I didn't really understand this explanation as from my limited understanding TSH is what stimulates the thyroid but t3 and t4 is what the thyroid actually produces, so I would think the "output" of the thyroid (t3 and t4) would be an indication of hypothyroidism.

I wanted a second opinion on this, since hypothyroidism runs in my family (my mom has it and takes medication for it) and some symptoms I have had recently match hypothyroidism (chronic constipation, sleeplessness, cold hands and feet, lack of tolerating cold outdoor temperatures).