If anyone is feeling mathematically up for it, a new paper has just come out:
A novel minimal mathematical model of the hypothalamus–pituitary–thyroid axis (HPT) validated for individualized clinical applications
Simon L. Goede, Melvin Khee-Shing Leow, Jan W.A. Smit, Johannes W. Dietrich, Mathematical Biosciences Volume 249, March 2014, Pages 1–7
HIGHLIGHTS are:
1) Presenting a parameterized minimal model of the hypothalamus–pituitary–thyroid (HPT) axis.
2) Model validation over different geological locations illustrates the physiological realism.
3) Homeostatic set point presentation by the intersection of the HP and thyroid curves.
Translates standard reference ranges to individualized set point based therapeutic treatment.
Note the last two points above. They have a method of determining how an individual's optimum set point can be measured by the crossover point of two aspects of thyroid function; the HP and thyroid function relations. Also the last point acknowledges the shortcomings of a rigid application of the reference range to an individual and instead assesses a therapeutic treatment that is in each case unique to the patient as an individual and not as a statistical entity fitted into a preset reference range.
These people are tops in their field, but it'll be well above the heads of the medical gurus, endocrinologists and GPs for a while yet so don't expect mea culpas any time soon.