TSH overly suppressed?

Hi Doc ~

I'm re-posting because in a previous post I mistakenly gave an incorrect level of my TSH.  I apologize for the mistake!

I'm having hyperthyroid symptoms such as heat intolerance, fatigue, exercise induced tachycardia, weight loss, and irritability. With only slight variations for the last 18 months my TSH = 0.01 and T-4 = 1.20.  This is at the lower end of the normal range.

Is it possible to get symptoms of hyperthyroidism when my levels are within the lab reference range, but at the low end of the range?

I'm in the process of a series of tests working with my cardiologist and PCP to find the cause of my symptoms.  The cardiologist suspects IST) inappropriate sinus tachycardia of possible thyroid origin.

My PCP currently has me on 150 mcr of Synthroid for hypothyroidism, but in the last 6 months I have developed distinct hyperthyroid symptoms.

I would greatly appreciate your thoughts! I apologize for having to repeat the question.

P.S. Thanx for providing this great service!!

[Mark Lupo, M.D.]

The TSH is low -- 0.01 -- meaning too much synthroid -- this can cause hyper symptoms.