T3 Uptake
T3 uptake measures how much labelled T3 binds to a test sample, which in turn reflects how saturated the body's thyroid-hormone-binding proteins are. The result is mainly used to interpret total T4 readings in context.
Why it matters: T3 uptake adjusts total T4 readings for changes in thyroid-binding-globulin levels — which can shift during pregnancy or with estrogen-containing medications. Modern panels often use direct free T4 testing instead.
May increase with:
May decrease with:
What is T3 Uptake?
T3 uptake measures how much labelled T3 binds to a test sample, which in turn reflects how saturated the body's thyroid-hormone-binding proteins are. The result is mainly used to interpret total T4 readings in context.
What might a high or low T3 Uptake mean?
T3 uptake adjusts total T4 readings for changes in thyroid-binding-globulin levels — which can shift during pregnancy or with estrogen-containing medications. Modern panels often use direct free T4 testing instead.
What can affect T3 Uptake?
It may be higher with: High TBG, Estrogen therapy, Pregnancy. It may be lower with: Low TBG, Androgen therapy, Liver disease.
Track your T3 Uptake over time
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