Help understanding Thyroid lab results...

[Fireproof]

Can you fine folks help me understand what my results may indicate? Why would TSH and Free T3 look okay, but Free T4 be so low?

- TSH = 0.984 (range 0.45 - 4.50)
- Free T3 = 3.2 (range 2.0 - 4.4)
- Free T4 = 0.58 (range 0.82 - 1.77)

I'm currently on 60mg/day of Amour Thyroid medication and have been for about 3 years.

Thanks.