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Beaumont Laboratory

Free T4 (Thyroxine) by Equilibrium Dialysis

This test is subject to pathology approval prior to sending to the reference laboratory for testing., ARUP #93244, Order as a Miscellaneous Sendout.


This test is only available to Endocrinologists and Nuclear Medicine Physicians.

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube.
Also acceptable: one Red top tube.

Physician Office/Drawsite Specimen Preparation

Centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 2.0 mL serum, refrigerated (2-8°C or 36-46°F). (Min: 0.3 mL)

Rejection Criteria

  • Specimens not collected and processed as indicated.


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 4 days
Refrigerated (2-8°C or 36-46°F): 2 weeks
Frozen (-20°C/-4°F or below): 1 month

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Sendout Laboratory with any questions.


Sent to ARUP Laboratories, Salt Lake City, UT.


Sunday, Tuesday, Thursday.
Results available in 2-7 days.

Reference Range

By Report.

Test Methodology

High Performance Liquid Chromatography-Tandem Mass Spectrometry.


By Report.

CPT Code


Test Codes

ARUP #93244, Order as a Miscellaneous Sendout.

Last Updated


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This directory currently reflects information only for specimens collected and/or processed at the Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.