Confused about lab results

[Timmersby]

Hello community, I need some advice please.

I was on a combination of T3 and thyroxine for many years with my Hashimotos symptoms reasonably well controlled. I was under the care of a progressive endocrinologist who understood about TSH suppression.

However, I recently moved back to Australia where T3 is not readily available and my endocrinologist wanted me to try taking just thyroxine for a period to see how I felt.

So, after reluctantly 8 weeks of taking just 150mcg of thyroxine, I have put on weight despite no change to diet and exercise plan, feel foggy, sluggish and just unwell.

That is no surprise of course after stopping T3, but I have just received my latest blood work and am confused about my TSH still being so low after 8 weeks of not taking any T3 but thyroxine alone. I know the endocrinologist will have a fit when she sees the results, and will tell me my FT3 and FT4 are normal and I don't need T3 given my TSH is so suppressed, so before I go in to see her next week I thought I would check in with this experienced community to see what your thoughts were.

My lab results were:

- Free T3 3.92 pmol/L (Reference Range 2.64-5.43

- Free T4 15.03 pmol/L (Reference Range 9.00-19.00)

- TSH <0.0083 uIU/mL (Reference Range 0.35-4.94)

There was a 24 hour gap between my last dose of thyroxine and the blood tests.

How long after stopping T3 would it take for my TSH to increase to levels within the reference range? I certainly don't have any symptoms of sub-clinical hyperthyroidism, in fact the opposite ! So am very confused and would like to be more informed before I go into battle with my new endocrinologist.

But to add some additional context, I had a prolactin test as well and it came back as follows:

- Prolactin 2.55 ng/mL (Reference Range 5.18 - 26.53)

Given TSH is a pituitary hormone, perhaps the issue is that I have a pituitary issue as well as a thyroid issue and that is the cause of the TSH issue ?

Thank you all in anticipation of your support.

Tracey

[SlowDragon Administrator]

FT4: 15.03 pmol/l (Range 9 - 19)

Ft4 is 60.30% through range

FT3: 3.92 pmol/l (Range 2.64 - 5.43)

Ft3 is 45.88% through range

It can take many months for TSH to respond if been suppressed, or TSH might never respond

You probably have room for small dose increase in levothyroxine

But perhaps first test vitamin levels

When were vitamin D, folate, B12 and ferritin levels last tested. Levels frequently drop when T3 is withdrawn

What vitamin supplements are you currently taking

As you have Hashimoto’s are you on strictly gluten free diet or dairy free diet

[Timmersby in reply to SlowDragon]

Thank you SlowDragon, I was not aware of the possibility of my TSH not responding; that is very interesting feedback. My vitamin D levels were at mid reference range so that could do with a bump; I have been taking 50,000iu per week. I have not had recent folate, B12 or ferritin tests so will get those next week. In addition to the Vitamin D3 supplements, I am taking 200mcg of selenium, magnesium citrate, and calcium (I have osteopenia). I follow a gluten free diet, but while I use plant based milks, I still sometimes eat cheese. I will get my vitamin levels tested and go from there - thanks again for taking the time to respond and give such clear advice.

[DippyDame]

I'd be more concerned about raising your FT3,. It is on the low side which will cause your symptoms of undermedication

Your FT4 is also low so you have room to increase your levo dose , this hopefully should convert to give you more T3 - a higher FT3. I would raise FT4 towards top of the reference range initially with more levo.

Add 25mcg, stay on that stable dose for at least 6 weeks then test.

If 175mcg ( even 200mcg) levo doesn't help then you will need to source T3

Increases must be low and slow

You will not be overmedicated unless FT3 reaches over range

However, I suspect your conversion is poor....high FT4 with low FT3.... but difficult to be sure after medication.

It looks as if you may ultimately need to return to T4/T3 combo.....time and testing will tell.

Might you be able to source NDT, if not T3?

TSH may not rise for a long time following T3-only treatment....it really doesn't matter though medics don't understand this.

I need high dose T3-only and my TSH and FT4 have "disappeared", my GP freaked out and thought I was killing myself until we had a discussion about it...she now leaves me to self treat my hypothyroidism!! Few medics are so open minded!

The important reading is FT3 followed by FT4.

T3 is the active thyroid hormone and for good health must saturate nearly every cell in the body by way of a constant and adequate supply.

This might help ...

thyroidpatients.ca/2021/07/...

bmcendocrdisord.biomedcentr...

"Time for a reassessment of the treatment of hypothyroidism"

Optimise vit D, vit B12 folate and ferritin to support thyroid function

Gluten free diet for Hashi's....maybe also try lactose free.

Good luck!

[Timmersby in reply to DippyDame]

Hi DippyDame, thank you so much for taking the time to reply and provide such comprehensive advice.

I read those articles with great interest and have printed them out in readiness for my GP visit next week. You are quite correct about my inability to convert T4 to T3, that is certainly what my previous endo told me, so I think I might try and do what I can to source T3 again. I have only ever felt 'well' taking T3 !

But first I will get my vitamin levels checked and increase my levo by 25mcg and then have everything checked again. As you suggest, I suspect this wil not do much to improve my T3 levels, but at least I will be doing something. I will also try cutting down on dairy products, and use lactose free options where I can.

Thanks again, it is such a relief to have people like you on a forum like this to help navigate the minefield of conflicting information pedalled by GPs and Endos !