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Common causes of a low Total Thyroxine (Total T4)
- Hypothyroidism
- Low binding proteins
Looking for the other direction? See what causes a high Total Thyroxine (Total T4).
All tests · Thyroid Function · Total Thyroxine (Total T4)
Below the range
What causes a low Total Thyroxine (Total T4)?
Normal range 5-12 µg/dL (64-154 nmol/L SI). Specimen: Serum. See the full Total Thyroxine (Total T4) reference page for critical values and nursing considerations.
What is the normal range for Total Thyroxine (Total T4)?
The standard teaching reference range for Total Thyroxine (Total T4) is 5-12 µg/dL in conventional units, or 64-154 nmol/L in SI units. This value is measured in serum.
| Specimen | Serum |
|---|---|
| Conventional range | 5-12 µg/dL |
| SI range | 64-154 nmol/L |
| Panel | Thyroid Function |
Full details, including nursing considerations, on the Total Thyroxine (Total T4) normal range page. Reference ranges vary by laboratory, method, age, sex, and population - always use the range printed on the actual result.
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