Dear Elaine, About seven years ago I was diagnosed with Hashimoto's and in 2014 my endocrinologist said I may have switched to graves or thyrotoxicosis but overall couldn't help as I had a 'curious' case. He did prescribe tapazole as my thyroid numbers were hyper. I took a very low dose for a couple of months and my labs went back in range. Since then, my thyroid labs have been in the range but my most recent test came back with the TSH low. My TPO antibodies are still high). My question is, is this just a temporary hyper stage and should I consider medication? Or, are my numbers OK and wait another month to see what the levels are at? When the TSH is low but T4 and T3 are in the range, is there reason to be concerned? Thanking you in advance!

TSH 0.01 (0.32-5.04 mU/L)
T4Free 17.1 (10.6-19.7 pmol/L)
T3Free 5.57 (3.00-5.90 pmol/L)

TPO 779 (<35IU/mL) - March 2017

TSH Receptor Ab 5.5 (<1.8 IU/L) - tested in 2014

Hi,
when TSH is low but thyroid hormone levels are normal, this is considered subclinical hyperthyroidism, a condition that's watched with repeat labs but it's not treated as meds could cause levels to fall too low.
Your 2014 TSH receptor antibody suggests Graves' if you were hyperthyroid although you probably also have or had blocking TSH receptor antibodies. TPO antibodies are markers of thryoid inflammation and don't contribute to the disease process. Studies show that adequate Vitamin D levels using vitamin D3 supplements and also 200-400 mcg selenium daily can help lower TPO antibodies.
You can't tell if this is temporary although most subclinical hyperthyroid disorders do resolve on their own. You'll want to have repeat labs in 2-3 months or sooner if symptoms change. best, elaine