Reverse T3
Reverse T3 (rT3) is an inactive form of the thyroid hormone T3. Elevated levels can indicate conditions like hypothyroidism, chronic illness, or high physiological stress.
Category: Thyroid Panel
Also known as: t3 reverse, lc/ms/ms
Reference range: 8–25 ng/dL (Source: ABIM)
Standard unit: ng/dL
High values may indicate
Elevated reverse T3 may indicate thyroid dysfunction, prolonged fasting, or chronic illness (euthyroid sick syndrome).
Low values may indicate
Low reverse T3 is generally not clinically significant.
Frequently asked questions
- What is a normal Reverse T3 level?
- A typical reference range for Reverse T3 is 8–25 ng/dL (source: ABIM). Reference ranges vary by laboratory, age, and sex, so always compare against the range on your own lab report.
- What units is Reverse T3 measured in?
- Reverse T3 is most commonly reported in ng/dL. Labs in different countries may use other units — you can convert between them with BloodId's blood test unit converter.
- Where do Reverse T3 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 Reverse T3 over time?
- Yes. Upload results from any lab and BloodId charts your Reverse T3 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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