HealthUnlocked posts by diogenes about thyroid ratios:
Relationship of FT3/FT4 ratio to cardiac mortality
FT3/FT4 ratio best at indicating osteoporosis in men
A Thyroid Patients Canada article by Tania S Smith:
An example of confusion about Free T3: Free T4 ratio
https://thyroidpatients.ca/2021/08/02/confusion-about-ft3-ft4-ratios/
Other Papers
Triiodothyronine/Thyroxine Ratio as a Marker of Clinical Response to Levothyroxine Replacement in Patients With Hypothyroidism
A
low T3/T4 ratio was significantly associated with resistant symptoms of
hypothyroidism and may be used as a marker for treatment efficacy with
TSH rather than TSH value alone.
Calculating T4:T3 ratios
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| Screenshot of a thyroid calculator |
https://thyroid.chingkerrs.online/
If you calculate a ratio based on results from one lab, and then compare to results from another lab, one which uses different reference intervals, the ratios will not be the same.
If the reference intervals are not the same, you have to accept that smaller variations in calculated ratios are difficult or impossible to interpret. Only the most obvious, larger variations are really useful.
Any attempt to try to make allowances for differences are likely to be questionable. You could introduce issues rather than resolve them.
Note: If you are calculating a T4:T3 ratio, it is essential that the results are in the same units. That is, do not mix up pg (picograms) and pmol (picomoles).
Another note: You might well see the ratio at T4:T3 or T3:T4. There is no universal standard.
Yet another note: It is common for people to make ratios have a "1" on one side or the other. Imagine you have a ratio of 10:2. You could divide by 2 to make that 5:1. Or divide by 10 and make that 1:0.2. They are all the same ratio. Scaling like this can make it easier to see whether one ratio is higher or lower than another.
If you wish to link to this page on HealthUnlocked, copy the entire dark red text below and paste into a post or reply:
[i][b]helvella - T4:T3 Ratios[/b]
Some notes and links about calculating T4:T3 ratios and what they mean.
Last updated 10/02/2025[/i]
Link to blog:
https://helvella.blogspot.com/p/helvella-t4t3-ratios.html
If you find anything incorrect, misleading, typos, links that don’t work, etc., please let me know. Go to my profile and use the contact details there.
