What does this test include?
The panel measures TSH, free T4 (FT4) and free T3 (FT3). The combination helps assess how the thyroid gland is being managed and functioning.
Why might it be ordered?
- For a more detailed assessment when symptoms are present or a previous thyroid test was abnormal.
- To monitor the function of the gland and the effect of treatment when prescribed.
What sample is needed?
A healthcare professional collects a venous blood sample. Depending on the method, the laboratory uses serum or plasma.
How should you prepare?
For follow-up testing, try to have samples collected at a similar time and under similar conditions. Tell the laboratory if you take thyroid hormone or biotin. Tell the laboratory about all medicines, hormone treatments, vitamins and supplements you take. Do not stop or change treatment unless your clinician tells you to. Follow any instructions about fasting and the time of collection.
How are the results reported?
TSH and free thyroid hormones are interpreted together; an abnormal result in one marker should not be considered in isolation. Your result is interpreted using the reference interval on the laboratory report and in the context of your symptoms, medical history and other test findings.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.