T3 Uptake
T3 Uptake (also called T3 Resin Uptake or T3RU) is an indirect measure of thyroid hormone binding capacity. It helps estimate free thyroxine index when combined with total T4.
Category: Thyroid Panel
Also known as: t3 uptake
Reference range: 24–39 % (Source: ABIM)
Standard unit: %
High values may indicate
High T3 uptake may indicate hyperthyroidism or decreased thyroid-binding globulin.
Low values may indicate
Low T3 uptake may indicate hypothyroidism or increased thyroid-binding globulin (e.g., during pregnancy).
Frequently asked questions
- What is a normal T3 Uptake level?
- A typical reference range for T3 Uptake is 24–39 % (source: ABIM). Reference ranges vary by laboratory, age, and sex, so always compare against the range on your own lab report.
- What units is T3 Uptake measured in?
- T3 Uptake is most commonly reported in %. Labs in different countries may use other units — you can convert between them with BloodId's blood test unit converter.
- Where do T3 Uptake reference ranges come from?
- BloodId uses ABIM standard reference ranges and educational information from MedlinePlus (see our methodology). Reference ranges still vary by lab, age, and sex, so always compare against your own report.
- Can I track T3 Uptake over time?
- Yes. Upload results from any lab and BloodId charts your T3 Uptake over time against its reference range, so you can see whether the trend is rising, falling, or stable.
Related biomarkers
Source: BloodId admin-reviewed
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