Thyroid Feedback Quantile-based Index
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SynonymsTFQI, PTFQI
Reference range–0.74 – +0.74
TestofSensitivity of TSH-producing pituitary cells to thyroid hormones; also a marker for the set point of thyroid homeostasis
| Thyroid Feedback Quantile-based Index | |
|---|---|
| Synonyms | TFQI, PTFQI |
| Reference range | –0.74 – +0.74 |
| Test of | Sensitivity of TSH-producing pituitary cells to thyroid hormones; also a marker for the set point of thyroid homeostasis |
The Thyroid Feedback Quantile-based Index (TFQI) is a calculated parameter for thyrotropic pituitary function. It was defined to be more robust to distorted data than established markers including Jostel's TSH index (JTI) and the thyrotroph thyroid hormone sensitivity index (TTSI).
Reference range
The TFQI can be calculated with
from quantiles of FT4 and TSH concentration (as determined based on cumulative distribution functions).[1] Per definition the TFQI has a mean of 0 and a standard deviation of 0.37 in a reference population.[1] This explains the reference range of –0.74 to + 0.74.
| Parameter | Lower limit | Upper limit | Unit |
| TFQI (PTFQI) | –0.74 | +0.74 | |