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Hormone Tests

Free T4

Measures unbound, active thyroxine hormone. Used with TSH to evaluate thyroid function.

CPT code

84439

Turnaround time

24–72 hours

Fasting required

No fasting needed

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About this test

Measures unbound, active thyroxine hormone. Used with TSH to evaluate thyroid function.

How to prepare

  • 1

    Bring a valid photo ID to your appointment

  • 2

    Plan for a 15–30 minute visit

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