All lab markers

Thyroid

Free T4

The storage form of thyroid hormone waiting to be converted to T3. Lower results are the ones to watch.

What commonly moves it

  • TSH
  • Thyroid autoimmunityAntibody-driven gland damage shifts TSH and free hormone levels.

What it can affect downstream

Free T3

These are commonly described physiological relationships, shared for education. They are not a diagnosis and cannot account for your medications, history, or symptoms — discuss your results with a licensed clinician.

Watching Free T4 over time?

Dose Compass charts each draw, flags meaningful moves, and helps you prepare questions for your clinician.

Start tracking