Browse Medical Laboratory Calculators
Total T3 Unit Converter
Triiodothyronine (Total T3) is the active form of thyroid hormone. While less abundant than T4, it is significantly more potent. The vast majority of T3 circulating in the blood is bound to proteins, but the “Total T3” measurement includes both bound and free forms.
Total T3 is often used to diagnose hyperthyroidism (T3 toxicosis) and to monitor treatment response. This converter facilitates switching between the standard mass units (ng/dL) and SI molar units (nmol/L).
Mass Units (US)
StandardNanograms per deciliter (Common US Unit).
SI Units / Molar
Nanomoles per liter (International Standard).
Clinical Context
Reference Ranges (Adults):
• Conventional: 80 – 200 ng/dL.
• SI: 1.2 – 3.1 nmol/L.
Interpretation:
• High Total T3: Hyperthyroidism, T3 toxicosis, or elevated binding proteins (e.g., pregnancy).
• Low Total T3: Hypothyroidism, or “Euthyroid Sick Syndrome” (low T3 syndrome) in severe non-thyroidal illness.
Conversion Logic:
Molecular Weight of T3: ~650.97 g/mol.
1 ng/dL ≈ 0.01536 nmol/L.
1 nmol/L ≈ 65.1 ng/dL.
Clinical References
How to Use This Converter
Follow these steps to normalize Total T3 values.
Enter Values
Input your laboratory result into the corresponding unit field (e.g., ng/dL).
Automatic Conversion
The calculator converts between mass units and the SI molar unit using the molecular weight of 650.97 g/mol.
Reset
Use the Clear button to reset all fields.
Frequently Asked Questions
It is most useful for diagnosing hyperthyroidism. Some patients have a “T3 toxicosis” where TSH is low and T3 is high, but T4 remains normal.
Less common than ng/dL, but sometimes used. 1 ng/mL equals 100 ng/dL.