puzzled by result of ft3 : can anyone explain... - Thyroid UK

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puzzled by result of ft3

Digger031145 profile image
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can anyone explain why my ft3 result would be lower although I had increased the dose ?

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Digger031145
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greygoose profile image
greygoose

I doubt anyone can explain anything without more information:

- results and ranges of TSH/FT4/FT3 before and after increase

- how much are you taking and how much did you increase by?

- how long have you been on the increased dose?

There are so many variables that we need as much info on the subject as we can get. :)

Digger031145 profile image
Digger031145 in reply togreygoose

I’ve only had my ft3 result back so far .

Prior to this latest test I was taking 100 t4 plus 20 t3.

Previous result was 3.83 (2.6-5.7)

This result 3.77 same range but increased to 25t3

greygoose profile image
greygoose in reply toDigger031145

OK so there's not a lot of difference. And a little variation is not unexpected. But, how long have you been on the 25 mcg T3? And, did you reduce the T4 dose when increasing the T3?

Digger031145 profile image
Digger031145 in reply togreygoose

I did not reduce the T4 as I’d already reduced it from 125 to 100.

I’d been on the increased dose 4 weeks.

When I was on 125t4 and 15t3 my results were;

19/9/23 last dose 8.30 previous day. Dose 125mcgs Levo 15mcgs t3 24hr gap

TSH <0.03( 0.34-4.94)

FT4 15.3(9-19) 63%

FT3 4.12(2.6-5.7) * 49.03%

When on 100t4 and 20t3 my results were:

5/12:23

Last dose 8.30 previous day. 24 hr gap from last dose

100mcgs Levo 20mcgs T3 ( this is reduced Levo increased t3

Tsh <0.3(0.34-4.94)

Ft4 11.9(9-19) 29.9%

Ft3 3.83(2.6-5.7) 42.9%

TiggerMe profile image
TiggerMeAmbassador in reply toDigger031145

It would suggest to me that you are missing out on the small amount of fT3 your higher fT4 was able to convert into... I'd increase your T4 to 125mcg.

It's all a bit odd when T4 doesn't do it for you but once you add T3 most people need to keep fT4 above 50% to get the true benefits of the T3 🤷‍♀️

Which dose have you felt best on?

Digger031145 profile image
Digger031145 in reply toTiggerMe

I reduced t4 because I had over range Rt3.

So I think I need to increase the T3 a bit more. I felt better when my ft3 was in the 4’s.

My muscle pains and weight increase started again when the ft3 was 3.83 which is why I increased the t3,

TiggerMe profile image
TiggerMeAmbassador in reply toDigger031145

Getting a little confused with your results but it looks like when you reduced to 125mcg

Tested 09./09/23 Genova

Levo 125mcgs plus 15mcgs t3. 24hrs gap

Last dose 8.20 previous day

TSH <0.01(0.40-2.50)

Ft4 16.22(7.86-14.41) 127.63%

Ft3 4.6(3.8-6.0) 36.36%

Rt3 0.57(0.14-0.54)

Ratio ft4/ft3 3.5

Then your results 10 days later...

When I was on 125t4 and 15t3 my results were;

19/9/23 last dose 8.30 previous day. Dose 125mcgs Levo 15mcgs t3 24hr gap

TSH <0.03( 0.34-4.94)

FT4 15.3(9-19) 63%

FT3 4.12(2.6-5.7) * 49.03%

Which I would say put fT4 in a good place? Perhaps you reduced again too quickly before the full extent of the drop from 150mcg to 125mcg had fully kicked in? With the 19/9 results I would have suggested a small increase in T3 rather than another drop of T4

Moving your T4 dose by 25mcg jumps is probably too large to find your sweet spot, when you think you are getting close smaller changes are needed

Digger031145 profile image
Digger031145 in reply toTiggerMe

I don’t know why I put genovactests there🥰. I didn’t intend to . I meant to put onky ngs tests from same lab.

I am trying to get my ft3 level back up to over 4.5 as that’s when my muscle pains stop abd start again when it drops to below 4.1.

So the easiest was is to increase t3 as t4 is just the storage hormone and my conversion is not as good as it was several years ago

TiggerMe profile image
TiggerMeAmbassador in reply toDigger031145

Shouldn't make too much difference which lab if you turn the results into % it makes it easier to compare the fluctuations

Digger031145 profile image
Digger031145 in reply toTiggerMe

can you tell me where I have ousted Genova results here in this thread as I can’t see them here

TiggerMe profile image
TiggerMeAmbassador in reply toDigger031145

They were in a previous post

Digger031145 profile image
Digger031145 in reply toTiggerMe

Oh I see.

Well I think they should be ignored as they’re so old and irrelevant to this current postv

greygoose profile image
greygoose in reply toDigger031145

So, you have a false low FT3 there, anyway. You're supposed to leave 8 to 12 hours between the last dose of T3 and the blood draw, not 24 hours.

And four weeks was too soon to test. Better to leave at least six weeks after a dose change to give things time to settle down. So, I wouldn't take much notice of that second test.

Digger031145 profile image
Digger031145 in reply togreygoose

I know it’s a false low for ft3 but I wanted to test to be consistent to my other tests.

However, it was actually 5 weeks since the last test and I was told that as I was only increasing the t3 & not the t4 that 3-4 weeks was long enough

greygoose profile image
greygoose in reply toDigger031145

OK, well, these things happen. I don't think there's any logical explanation that anyone can give you. But, it could have something to do with the reduction in levo catching up with you. Sometimes it takes quite a while.

Ft4 16.22(7.86-14.41) 127.63%

Are you absolutely certain about that range? It looks a bit weird.

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