Hi there - can anyone tell me with a range of
Free T4
• 16.8 pmol/L
• Range:9 - 23 pmol/L
• Date:12 Mar 2024 13:01:00
and T3 range
5.5 pmol/L
Range:2.4 - 6 pmol/L
Date:12 Mar 2024 13:01:00
what the percentage of T4 etc. would be - someone I think it was greygoose was giving a figure to someone a few weeks back. Hope this makes sense I think I know what I mean !
put result and ranges into here . it will give you the % through range .
FT4: 16.8 pmol/l (Range 9 - 23) 55.71%
FT3: 5.5 pmol/l (Range 2.4 - 6) 86.11%
Thanks so much for your prompt reply - does that mean I have to add up the T4 and T3 together - if so am I over medicated. Don't feel like I am but just checking.
no .. don't add them together .
look at them in isolation. .. sorry got brain fade now .... might reply further when brain comes back.. or might not . all the best Tat x
Sorry I hope I am not the cause of that ?
no ... definitely not you, worry not 
helvella - T4:T3 Ratios
Some notes and links about calculating T4:T3 ratios and what they mean.
helvella.blogspot.com/p/hel...
Brilliant help thanks very much.
I have an ongoing quibble with using test results to get ratio's helvella .
any thoughts would be appreciated .
Different fT4 ranges can significantly affect the resulting ratio.
eg:
fT4 22 [12-22] fT3 4 [3.1-6.8] T4:T3 ratio = 5.5 (lousy conversion)
but if an equivalent (100% through range) fT4 level is reported from machine using [7.9-14[ range ... then
fT4 14 [7.9-14] fT3 4 [3.1-6.8] T4:T3 ratio = 3.5 (much better conversion)
they can't both be right .
The lower [7.9-14] range skews the outcome significantly.
So anyone with bloods done on eg. [7.9-14] range can't really use ratio's as a reliable guide. or at least they can't compare them to ratio's achieved using eg [12-22]
but i never see this potential issue mentioned. and there are significant numbers of NHS fT4 results done using Beckman Coulter[7.9-14] ish range .. Morecambe Bay , and Bristol do. and presumably there are others.
posthinking01 ... there is a difference between 'ratio' and '% through range'
the above is mainly a question for Helvella .
but you may find this post helpful if you want to try and understand 'ratio'.... healthunlocked.com/thyroidu.... working-out-t3-t4-ratios...-or-t4-t3-ratios...-trying-to-understand-the-different-methods-and-understanding-the-results.
( when you see people putting % on here it is the '% through range' they are describing , not the 'ratio' )
You are absolutely right. If the tests are not equivalent, the ratios cannot be equivalent.
For that reason, smaller variations in ratio really have to be regarded as having little basis in science/reality.
(And we see pretty much the ultimate of that when we see this done using units typical of USA labs. The ratios are massively different.)
Thankyou
Have updated my blog to mention that.
Hi does the fact that I am showing as 55.7 per cent and I have no thyroid - that there is capacity to raise my T4 further.
It would appear so but I have not looked properly.
But am a little confused by the fact that the post started by being about the ratio rather than the percentage through reference interval.
Hi oh that's me getting the word wrong - I wasn't sure what it was I had seen in a previous post a ratio or percentage. I notice that most people who have no thyroid are on 200 mcg - I probably wouldn't take T3 as well but interesting to see if I convert if I get up to that figure eventually over time.
Ha!
Right - I'd be very wary of looking at what other people take. Some people might absorb levothyroxine very much less effectively than others. That factor alone could see one person taking double, triple or more than another person.
And those taking liquid forms seem to need slightly less (in terms of micrograms of levothyroxine).
But if you do decide to increase, go slowly.
Thanks so much - was losing my eyelashes in total not long ago - and hair falling out all the time - yet tests showed OK at middle of range I should have known that I only function well at the higher range but have to up my steroid for a time to support the surge on the adrenals. Thanks so much for your help and support.
Are you only on (liquid) Levo or taking T3 as well?
Was test done as recommended early morning, ideally just before 9am, only drink water between waking and test and last dose levothyroxine 24 hours before test
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)
If on T3 ….day before test split T3 as 2 or 3 smaller doses spread through the day, with last dose approximately 8-12 hours before test
Looking at same results in previous post
healthunlocked.com/thyroidu...
Your recent weight loss was being investigated as possibly coeliac
Are you now on gluten free diet ?
And/or dairy free diet?
Hi there - no I can't do all that not taking before a test - I have to travel by car to London for my appointment from Surrey and would feel very unwell if I didn't have my thyroid meds even though it is said it stays in the system - my adrenals would not be happy and I could go dizzy as they tried to compensate ! Yes on liquid now had to up it to 130 mcg - thyroid atrophied - and taking 10 mcg of T3 all in one go now - splitting the dose was not working for me. Yes celiac/gluten intolerance - lost 42 pounds so far - had to cancel endoscopy as had problems with collagen issues and my tongue was swollen (low B12/thyroid as well I know). Yes dairy free as lactose intolerant - was gluten free for 6 months but have now 'developed' a problem with the ingredients of gluten free products - rice I believe - my eyes are going really dark underneath and I look very very ill - slowly introducing gluten back in - not too bad at moment but going very slowly. Have had terrible bruising for years on and off and have collagen issues - have just discovered that this problem could be in my case low thyroid hormone - I never knew that the thyroid was implicated in collagen process - upped my thyroid hormone and bruising disappeared in a day and can now open a door without my fingers bruising or washing up and bruising from holding cups etc. - thanks for your help.
So....to assess if there is any room for dose increases, we need to know how many hours before this test the last dose of Levo was taken ?
FT4: 16.8 (9 - 23) 55.71%
and how many hours before this test was last dose T3 taken ?
FT3: 5.5 (2.4 - 6) 86.11%
and what was TSH ?
and had you been on stable dose for at least 6 wks ?
Hi I take my thyroid meds about 7.30 p.m. T4 and T3 and my steroid - but then even though appointment maybe 11.00 a.m. by the time I get to having bloods taken it can be 1.00 p.m. !
Certainly wasn't greygoose! Greygoose hates ratios! lol
posthinking01,
The 'percentage' is how far through range your levels lie, so give an idea of the amount of FT4 or FT3 you have.
The 'ratio' relates to the amount of FT4 in relation to the amount of FT3 you have (or the other way around depending on how it is written).
Everyone has their own unique sweet spot which will comprise of the right levels of hormone in the right proportion.
Thank you - understood !
what is the desired T4:T3 ratio? (because I don’t think this is it)
is the T4:T3 ratio in NDT wrong?
T3/T4 ratio dosing query 
T3/T4 ratio is high - what does this mean?
