TSH
The first step in thyroid testing.
TSH is the signal your brain sends to your thyroid. The typical adult range is about 0.4–4.0 mIU/L; the upper limit can reach 4.5 depending on the lab.
| TSH (mIU/L) | Possible meaning |
|---|---|
| <0.4 | Thyroid may be overactive; checked together with fT4 and fT3 |
| 0.4–4.0 | Typical range |
| >4.0 | Thyroid may be underactive; checked together with fT4 |
- American Thyroid Association — hypothyroidism and hyperthyroidism guidelines
General information only; not diagnosis or treatment. Review your results with your clinician.
