This article explores thyroid hormones, how rT3 is produced, and its significance.
It also covers health conditions that can affect it.
An Overview of Thyroid Hormones
There are several thyroid hormones.
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Your healthcare providers look at these tests to determine which step or steps are responsible for your symptoms.
Laura Porter / Verywell
Production of rT3
Reverse T3 is a metabolite (byproduct) of T4.
Researchers believe the body produces rT3 in times of severe illness or starvation as a mechanism for preserving energy.
Measuring rT3
Reverse T3 can be measured by a blood test.
A level below 250 pg/ml (10 ng/dL to 24 ng/dL) is considered normal.
Just like T3, rT3 can bind to cells in the same way.
When T3 binds to cells, it interacts with thyroid hormone receptors.
However, when rT3 binds to a cell, no known physiological effects exist.
After recovery from the severe illness, the thyroid function test results should normalize.
Instead, a number of well-understood physical signs and laboratory tests guide these decisions.
No recent research suggests this is the case.
Summary
The precise meaning and significance of rT3 are still being determined.
Currently, no standardized guidelines exist concerning interpretation or treatment planning based on rT3 alone.
An analysis of practice variation based on order data from a national reference laboratory.Thyroid.
Gomes-Lima C, Burman KD.Reverse T3 or perverse T3?
Still puzzling after 40 years.Cleve Clin J Med.
2021;18(18):9434. doi:10.3390/ijerph18189434
