New paper showing inadequacy of TSH as a diagnostic tool and a method for best assessment of treatment

[diogenes]

We have a new paper out as below, discussing the relationships between TSH, FT4 and FT3 and the need to use all parameters in determining best treatment for those of thyroid hormone supplementation. It is available freely to download if required. We're trying to get a modelling programme that would automatically home in on the best "set point" for a patient based on at the moment FT4 and TSH values. FT3 is being included by a future refinement. This would allow a sound assessment of the treatment needed to achieve the best outcome.

Advances in applied homeostatic modelling of the relationship between thyrotropin and free thyroxine

doi.org/10.1371/journal.pon...

Rudolf Hoermann, John Edward Maurice Midgley, Rolf Larisch, Johannes Wolfgang Christian Dietrich

Abstract

Introduction

The relationship between pituitary TSH and thyroid hormones is central to our understand- ing of thyroid physiology and thyroid function testing. Here, we generated distribution patterns by using validated tools of thyroid modelling.

Methods

We simulated patterns of individual set points under various conditions, based on a homeostatic model of thyroid feedback control. These were compared with observed data points derived from clinical trials.

Results

A random mix of individual set points was reconstructed by simulative modelling with defined structural parameters. The pattern displayed by the cluster of hypothetical points resembled that observed in a natural control group. Moderate variation of the TSH-FT4 gradient over the functional range introduced further flexibility, implementing a scenario of adaptive set points. Such a scenario may be a realistic possibility for instance in treatment where relationships and equilibria between thyroid parameters are altered by various influences such as LT4 dose and conversion efficiency.

Conclusions

We validated a physiologically based homeostatic model that permits simulative reconstruction of individual set points. This produced a pattern resembling the observed data under various conditions. Applied modelling, although still experimental at this stage, shows a potential to aid our physiological understanding of the interplay between TSH decision making.

[JGBH]

Thank you Diogenes.

[Hidden]

Thank you. I came up with my own little theory about these blood tests and wondered if it is anywhere near reality. My thoughts are that tsh is gently undulating throughout the day, T4 is level as a store and very slowly changes and T3 mountainous with big drops and climbs. This would make the tsh a rough guide in a blood test, T4 the best marker for long term dosage decisions and dignostic purposes and T3 needs to be done to rule out conversion issues. I expect it is a lot more complicated than this.

[diogenes Remembering in reply to Hidden]

Actually in the healthy person TSH undulates very vigorously over 24 hours, FT4 hardly at all, and FT3 only slightly too with the only significant change in the night. However on therapy T3 taken in only lasts about a day and so FT3 then peaks and troughs quite seriously according to how long after the dose, the blood FT3 was measured.

[Hidden in reply to diogenes]

Thank you. That makes sense. I have suspected sometimes that Tsh can be really unreliable. My own as stayed between 2 and 5 untreated for most of my life. It seems that most doctors only see it as unreliable when it indicates treatment. So in my case when it has been just over the range they test again in 3 months despite glaring symptoms but if it is tested and below range it is accepted as reliable and I am not tested again despite glaring symptoms. I remember someone came on the forum once with a tsh of 50 and a prescription for 100mcg of levo but was not wanting to take as she was free of symptoms. Just a random peak maybe.

[amala57]

I will show this to my endo, although he takes no notice of anything I give him!

Thank you for doing this work!

[shaws Administrator]

I hope those doctors who deal with dysfunctions of the thyroid gland, read and absorb.

Thank you and your whole team for striving to get sense into those who treat suffering hypo patients

[dolphin5]

Thank you - that's another paper printed out to take to my next endo appointment.