It's so difficult to read the blood work and know what it means, there's about 50 T's on that page. I forget what exactly T3 is, i'm pretty sure it's what controls the metabolism. My doctor's just tell me the only thing they really look for on my blood work is the thyrogloblium level ( i don't know if that's spelled right) but that's what shows if there's any thyroid tissue growing in your body. But that's only important if you had your thyroid removed. I'm sure everythings fine though.