TSH, Free T3 and T4 — Thyroid Panel
TSH is the pituitary's signal to the thyroid; Free T4 and T3 measure thyroid hormone. Read together, they help show whether a problem starts in the thyroid or the pituitary.
TSH is made by the pituitary gland and tells the thyroid how much hormone to make, while Free T4 and T3 measure the thyroid hormones in the blood — read together, they help show whether a thyroid problem starts in the thyroid gland or in the pituitary.
Watch the 38-second version
TSH can look normal while the active hormone is not.
Transcript & sources → All videosMr. Age is AgeGen's editorial character. Facts come from the protocol above.
The biomarker
- Name: TSH, Free T3, and Free T4 — Thyroid Panel
- Units: TSH mIU/L; Free T3 and Free T4 per lab (commonly pmol/L)
- Standard reference range: TSH 0.4–4.5 mIU/L for a non-pregnant adult; read Free T3 and Free T4 against your lab's own range (ranges vary by lab)
How to read your result
| Result | Interpretation |
|---|---|
| High TSH + low Free T4 | May mean the thyroid is making too little hormone — see a clinician |
| Low TSH + high Free T4 | May mean the thyroid is making too much hormone — see a clinician |
| Normal or high TSH + high Free T4 | May mean a pituitary condition — see a clinician |
What moves the needle
- Testing. If TSH comes back abnormal, your clinician will probably order T4, T3 and thyroid antibody tests to find the cause.
- Clinician. Endocrinology referral if hypothyroidism or hyperthyroidism is confirmed.
Why this test is worth asking for
- TSH is the pituitary's signal to the thyroid: when T4 is low the pituitary makes more TSH, and when T4 is high it makes less.
- Reading TSH with Free T4 is what separates a problem in the thyroid gland from a pituitary condition.
- TSH is usually the first test ordered when screening for thyroid disease; T3 is usually ordered together with T4 and TSH.
Related protocols
Sources
- MedlinePlus — TSH (Thyroid-Stimulating Hormone) Test
- MedlinePlus — Thyroid Tests
- Cleveland Clinic — Subclinical Hyperthyroidism
AgeGen lab guides are educational only. We do not provide medical diagnosis, prescribe brands, or recommend specific doses. Talk to a licensed clinician before changing your supplement or medication routine.
