Serum Free T4 Levels?

My latest blood test gave a level of Serum Free T4 of 19.4 pmol/L (10.00 - 23.00 pmol/L)

doc says this is fine but is it? BTW, I was diagnosed underactive in 2008. I'm currently on 100mg of thyroxine. What is confusing is that every test gives a different level of what is 'normal'. How are we meant to know what's correct?

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T3 is what u need to be looking at

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Ok, I got Serum TSH at: 0.20 mlU/L (0.27 - 4.20mlU/L

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Hi, i believe that the reference range from different labs vary, so when you get your results, check the reference range to. Hope this helps....and is right!!!