Days Set Up
Daily, 24 hours
Analytic Time

4 hours

MiChart Code
T3 Uptake and FTI
Soft Order Code

Test Updated:


Free Thyroxine Index
Thyroxine Index, Free
Triiodothyronine Uptake

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Find a Requisition

All specimens should be accompanied by a requisition.

Submitting Specimens

Learn about how to properly label and where to ship specimens.

Order Kits and Supplies

MLabs provides all the supplies necessary for the collection of specimens.

Test FAQ

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Test Overview

Test Methodology

Competitive Immunoassay

Test Usage

Thyroid function test, for the diagnosis of hypothyroidism or hyperthyroidism in conjunction with T4 result.

Reference Range

22 - 37% Uptake

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Onsite

Collect specimen in a red top or SST tube. Test should be ordered in conjunction with a total T4.

Collection Offsite

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.

Yellow Top Tube
Normal Volume
0.5 mL serum
Minimum Volume
0.25 mL serum

Billing Information

CPT Code
Pro Fee Code

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.