Thyroid Panel
The thyroid panel measures hormones involved in thyroid function: TSH (the pituitary regulator), total T4 and free T4 (the primary thyroid hormone), and total T3 (the more potent active hormone produced largely by peripheral T4 conversion). Population reference values are derived from NHANES 2009-2012 Thyroid Profile Subsample A, excluding participants with self-reported thyroid disease or current thyroid medication use.
Also listed under Endocrine .
Frequently Asked Questions
Why are TSH, T4, and T3 measured together?
They describe different levels of the thyroid axis: TSH reflects pituitary signaling, T4 reflects thyroid secretion, and T3 reflects peripheral conversion and active hormone availability. The combined pattern is more informative than any single marker.
Why do these population distributions exclude people with self-reported thyroid disease?
Thyroid hormone levels are substantially altered by thyroid disease and medication. Including those participants would widen and shift the distributions in ways that reflect disease prevalence rather than the variation present in adults without a reported thyroid condition.