is FT4 of 15.2 considered low?

I'm diagnosed hypothyroid and been on T4 meds for 12 years, yet my condition has only continued to worsen despite any test except for anemia coming back "normal". These are the most recent tests but they are already 7 months old (I barely get tested once every two years). Until a few months ago I had no idea to request any other tests than the ones in this post, so my T3, adrenals and anything else have never been tested.

So, is that level of T4 considered low?

Serum free T4 level – 15.2 pmol/L (12.0-22.0)
Serum TSH level - 1.15 mu/L (0.4 – 4.0)

Thanks in advance :)

[Barb135]

Your Free T4 is very low in the range, indicating that you could use an increase in medication.  

You already mentioned the T3, so you're aware that you need to get FREE T3 tested.  Free T4 must be converted by the body to Free T3, which the hormone actually used by the individual cells.  Some of us don't convert adequately, so we have to add a source of T3, either in the form of generic liothyronine or in the form of a desiccated thyroid hormone.