Diagnostic test
Thyroxine Free (FT4)
About test
What does Thyroxine Free (FT4) measure?
The Free Thyroxine (FT4) test measures the unbound, active form of the thyroid hormone thyroxine in the blood. It may be used with other thyroid tests, such as TSH, to assess thyroid function and help investigate symptoms that may be related to an overactive or underactive thyroid. It may also help monitor known thyroid conditions or response to treatment. Results are interpreted alongside symptoms, medical history, and other test findings.
This overview is educational. Use the recorded preparation, sample and lab-partner details below for collection guidance, and confirm any missing information before collection.
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Prices, report times and availability are shown from the catalog records for each eligible partner.
Sagepath Labs
- Sample for analysis
- Serum (1 mL)
- Report time
- 11:00/18:00
Preparation and specimen requirements can vary by test and laboratory. Follow the instructions shown for your selected partner and any advice from your healthcare professional.