Mediki
T3 blood test: what your result means
T3 measures triiodothyronine, an active thyroid hormone that affects metabolism, heart rate, and energy use.
- Category
- Thyroid
- Standard unit
- nmol/L
- Reported in
- nmol/L, ng/mL, µg/L, ng/dL, ng%, ng/100ml and more
What does high T3 mean?
Higher values may suggest increased thyroid hormone activity. What counts as high depends on the reference range printed on your lab report, because ranges differ between laboratories.
What does low T3 mean?
Lower values may suggest reduced thyroid hormone effect or conversion. What counts as low depends on the reference range printed on your lab report, because ranges differ between laboratories.
T3 units and conversion
Mediki shows T3 in nmol/L. Labs may report it in other units; Mediki converts them automatically so results from different labs line up on one chart.
| Unit on your report | Convert to nmol/L | Convert back |
|---|---|---|
| ng/mL, µg/L | 1 ng/mL = 1.536 nmol/L | 1 nmol/L = 0.651 ng/mL |
| ng/dL, ng%, ng/100ml | 1 ng/dL = 0.01536 nmol/L | 1 nmol/L = 65.1 ng/dL |
| ng/L | 1 ng/L = 0.001536 nmol/L | 1 nmol/L = 651 ng/L |
Convert a value from your report with the blood test unit converter.
Why track T3 over time?
A single T3 result is a snapshot. Comparing it with your earlier tests shows whether a value is stable, slowly drifting, or responding to a change in treatment or lifestyle, which is often more useful than one number on its own.
Read our guide on how to read blood test results to understand reference ranges, flags and units.
Following T3 as part of a panel? See the thyroid test tracker.
Track your T3 results in one chart
Upload your lab reports and Mediki plots every T3 result against its reference range. Your first 15 pages are free.
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Medical disclaimer: This page is general information, not medical advice. Reference ranges differ between laboratories, and only a doctor can interpret your results in the context of your health.