Free T4
What it measures
Free T4 measures the unbound, active form of thyroxine, one of the main hormones your thyroid produces.
Often reported in ng/dL. Reference ranges differ between laboratories, ages and sexes, so always compare with the range printed on your own report.
Why it matters
Free T4 is typically interpreted together with TSH, since the two normally move in opposite directions to keep thyroid function balanced.
Questions worth asking
- How does this compare with my TSH result?
- Are there symptoms, like fatigue or weight changes, worth mentioning?
- Would checking free T3 add useful information?
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Educational information only. Not a diagnosis, not treatment advice, and not a substitute for a licensed healthcare professional.