4 hours
Test Updated:
Free Thyroxine Index
FTI
T7
Thyroxine Index, Free
Triiodothyronine Uptake
T3U
FREE THYROXINE INDEX
T3 UPTAKE
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Test Overview
Competitive Immunoassay
Thyroid function test, for the diagnosis of hypothyroidism or hyperthyroidism in conjunction with T4 result.
22 - 37% Uptake
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
Specimen Requirements
Collect specimen in a red top or SST tube. Test should be ordered in conjunction with a total T4.
Collect specimen in a red top or SST tube. Centrifuge, aliquot serum into a plastic vial and refrigerate. Test should be ordered in conjunction with a total T4.