Taking her hormone the evening before her test, won't have any effect on the TSH. It doesn't change that fast. Besides, the difference is negligeable. Were both tests done at exactly the same time of day?
The recommended time gap is 24 hours for T4, and 12 hours for T3. But, as you can't separate the T4 from the T3 in NDT, it's best to just leave 12 hours.
She's taking NDT, which contains T3. The FT4 will be low when taking any T3, because the body only hangs on to what it needs. And, the TSH is low, because she's taking T3.
However, she is under-medicated, because the FT3 - the only important number - is below mid-range. Most people need it up the top of the range to feel well.
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