Low TSH: Hi all, Underactive Thyroid diagnosed... - Thyroid UK

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Low TSH

ALW198 profile image
6 Replies

Hi all,

Underactive Thyroid diagnosed in 2018, have been taking 125 Levothyroxine since then with minimal changes in bloods in this time, well managed symptoms and not much to report.

Had routine bloods done in May to find a low TSH of 0.27, GP asked for bloods again in 3 months and have just had results through again for low TSH OF 0.27.

The test was done at 11am with meds taken at 6.30. I appreciate this doesn’t give optimal results but to be frank, I forgot. No food or drink was had for at least an hour after taking meds either.

I have recently found that I am getting pain and numbness in my fingers and also suffer with a sore, swollen throat at times which I know is thyroid related (not illness).

May: T3 4.7, T4 15.5

September: T3 4.4, T4 16

No full bloods were taken which I will push for in my follow up appointment at the start of October but I just wondered if anyone had any advice or thoughts on my results before then.

I understand that a low TSH points at an overactive thyroid so is it likely that they will lower my dosage now. Any thoughts on why things might have changed now?

I don’t take any other supplements.

Thanks in advance for any thoughts.

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ALW198 profile image
ALW198
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6 Replies

You have a false low TSH because you took your levo beforehand. Don't let the GP make any changes until you retest (fasted, before 9, no levo). Your T3 and T4 look quite low but do you have the ranges?

ALW198 profile image
ALW198 in reply to Dahliasanddaisies

Noted, thanks.

T3 range is 4.0-6.6 so on the low side

T4 is 7.9-20.0 so at the higher end

Dahliasanddaisies profile image
Dahliasanddaisies in reply to ALW198

T3 and t4 are pretty low, if you put them in the % calculator it'll show you what they are through the range. Considering you had taken your levo also.

healthunlocked.com/thyroidu...

greygoose profile image
greygoose in reply to Dahliasanddaisies

Not really, no. Taking levo before the blood draw does not affect the TSH because the TSH cannot move that fast. Taking levo too close to the blood draw would only affect the FT4. :)

DippyDame profile image
DippyDame

Research shows that TSH is not a reliable marker.

thyroidpatients.ca/2021/07/...

The important numbers are FT4 and FT3 so collating the info for your September labs and using %age calculator ( thyroid.dopiaza.org/?utm_so... ) we can compare the results

FT4 16 (7.9 - 20) 66.94% through reference range

FT3 4.4 (4 - 6.6) 15.38% ditto

BUT...

The test was done at 11am with meds taken at 6.30. I appreciate this doesn’t give optimal results but to be frank, I forgot. No food or drink was had for at least an hour after taking meds either.

Meds at 6.30 am and test at 11am is a waste of time because your results are a false high and any conclusions are little more than a guess!

There needs to be a 24 hour gap between last T4 dose and the test

I forgot is not going to help your condition.....we need results to be as accurate as possible otherwise it's difficult to offer helpful comment.....you need to help us to help you.

It's not easy and is dreary and boring but accuracy is key......took me over a year to establish my therapeutic dose but my thyroid condition proved to be both rare and complicated. But I learned a lot!!

A low TSH can mean you are overmedicated, it can also suggest a pituitary problem where the thyroid gland is not receiving messages from the pituitary gland to alter hormone production. Your last labs (FT4 and FT3) do not indicate an overactive thyroid (hyperthyroidism)

In any case if you are hypothyroid it is virtually impossible to become hyperthyroid.....Overmedication is often wrongly mistaken as being hyperthyroid!

You appear to be under (or wrongly) medicated.

You need to test again following correct protocol...

24 hrs after last T4 dose

At 9am to achieve highest TSH

Fasting overnight/ before test to avoid food and drink affecting hormone levels

Your GP should not adjust your dose based on those results....the problem is many GPs are not clued up on thyroid function/ disease.

It does however look as if you may have impaired T4 toT3 conversion.....low FT3 with relatively high FT4........but again accurate testing required

Çome back when you have new, accurate, results

KrazyKatMT70 profile image
KrazyKatMT70

Talk to your Dr about going one step up. From .125 to .137. That’s the next step.

Mine goes up and down with mainly my weight. I’ve been on .150 and went to .137 and .125 and now on .100mcg. But it’s not always about weight. At one time my TSH was below zero. But it’s in range now. Thyroid meds have to be raised or lowered slowly , not drastically. That’s why I say talk to your Endocrinologist or MD about it.

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