Diagnostic test
T4 (Thyroxine)
About test
What does T4 (Thyroxine) measure?
The T4 (thyroxine) test measures the level of thyroxine, a hormone produced by the thyroid gland that helps regulate metabolism, energy use, growth, and development. It may be used to assess thyroid function and to support evaluation of symptoms or conditions related to an overactive or underactive thyroid. Results are usually interpreted along with other thyroid tests, such as TSH and T3, and the person’s clinical history.
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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Compare eligible lab partners
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.