Total T3 measures the total amount of triiodothyronine in the blood, including both bound and unbound forms. T3 is the most active thyroid hormone and plays a key role in metabolism.
Category: Thyroid Panel
Also known as: total t3, t3, triiodothyronine, triiodothyronine total
Reference range: 80–200 ng/dL (Source: ABIM)
Standard unit: ng/dL
High values may indicate
High total T3 may indicate hyperthyroidism, Graves' disease, early thyrotoxicosis, or elevated thyroid-binding proteins (e.g., from pregnancy or estrogen therapy).
Low values may indicate
Low total T3 may indicate hypothyroidism, severe non-thyroidal illness (sick euthyroid syndrome), malnutrition, or decreased thyroid-binding proteins.