What did the T-uptake measure?
The T3-uptake (later versions called T-uptake methods) was the original test used to estimate thyroid binding protein levels. These are rarely used now that methods are available to directly measure free T4 and free T3.
Other names:
- Also known as thyroid binding capacity
Why was it ordered?
- Provides a measure of the available thyroxine-binding sites
What has replaced it?
- Free T4 (FT4) and Free T3 (FT3) immunoassays
