Can TSH be to low while on levo......?

[N314]

is there any reason why a TSH of 0.18mu/l would be considered ok (by a doctor) for someone who is hypothyroid & is on 75mg levothyroxine ? Surely there is a point where TSH is to low?

[pennyannie]

Hello N314

The TSH test was originally introduced as a diagnostic tool to be used, alongside clinical symptoms and judgement to confirm a diagnosis of hypothyroidism, and once on any form of thyroid hormone replacement, a TSH test used in isolation is pretty much useless, and just one of three blood test results, the other two being T3 and T4 that need to be looked at in conjunction to each other.

The TSH does come with a range - depending on laboratory used, but as said, used in isolation means virtually diddly squat once diagnosed and on thyroid hormone replacement though it does seem that in primary care that this maybe the only test run for thousands of patients at their yearly thyroid function test.

[N314 in reply to pennyannie]

Thank you for your reply - i am struggling to even find out if FT3 & FT4 were even tested ! i feel a private blood test route may be necessary.

[pennyannie in reply to N314]

Yes, if in primary care for routine monitoring, you'll probably just find a TSH blood test result and range :

If the TSH is high and over range a T4 blood test may have been run :

If the T4 came back high and over range a T3 blood test may have been run :

T4 is a storage hormone and T3 is the active hormone that the body runs on :

Hyperthyroid and hypothyroid are the opposite ends of the same T3 stick :

Too low a level of T3 and you may have symptoms of hypothyroidism whilst too high a level of T3 and you may have symptoms of hyperthyroidism.

There is a lot more information on the Thyroid UK website who are the charity who support this amazing forum, as well as a list of private companies who will run the appropriate blood tests for you.

If this is the way you see yourself going, it's recommended that you initially look to order a full thyroid panel to include inflammation, antibodies, ferritin, folate, B12 and vitamin D. and once with the results and ranges throw all the results and ranges back up on here for forum members to advise you on.

[pennyannie in reply to N314]

P.S. Welcome to the forum - apologies, thought I'd said this, but didn't, I'll get another coffee !!!

[N314 in reply to pennyannie]

Thank you for your help.......most informative..........😀

[pennyannie]

If your TSH is said to be too low and you are told you need a dose reduction of T4 - Levothyroxine and you feel ok on your dose -

Just say something like : -

" Well, that's funny as I don't feel over medicated at all - are my T3 and T4 blood tests results over range then, and can I have a copy of the blood test result please ? "

[shaws Administrator]

Few doctors know much at all about hypothyroidism. They only go by 'myths'. They believe a very low TSH means we've become hypERthyroid.

Before blood tests were invented and became the No.1 way to diagnose - strange that my TSH had to reach 100 before I diagnosed myself. They have lost the knack of knowing any clinical symptoms at all and we may get 'other prescriptions' for the 'symptom' rather than a decent dose of thyroid hormone replacements. Unfortunately 'those that we'd imagine knew better don't and only respond to the TSH alone.

TSH is from the pituitary gland and rises when our thyroid gland is struggling.

We have to educate ourselves and many of our members are much more knowledgeable than the professionals.

hormonerestoration.com/

It's surprising that many doctors are badly trained.

[N314 in reply to shaws]

Thank you .... great link 😀

[tattybogle]

For all thyroid blood tests . the Lab reference range that the test was done with is important to interpret the result. Even though lab ranges used for TSH test are much less varied than those for fT4 it does still make a difference to your question. "is there a reason why TSH 0.18 would be considered OK ?"

For example :-

for many years my NHS lab used a TSH test with range [0.02-6]

during that time i had TSH as low as 0.04 /0.06/0.09/ , and my fT4 was sometimes (but not always) well within range at these TSH levels.

When my TSH went to the dizzying height's of 0.12/0.18/0.69 my fT4 was only 50- 70%

So with that lab range my TSH of below 0.18 was considered fine and my dose was never reduced.

Even though my lab must have got new machines since then and therefore now use a different lab range [0.34-5.6] for a couple of years and now [0.57-3.6] i have still had instances of TSH of 0.061 with fT4 at just 59% ,and TSH 0.046 with fT4 111%. both pronounced OK by GP's.

From my own reading of research papers i'n not bothered by Low TSH unless it goes below 0.04.... and even then it's all relative to quality of life.

There's no point keeping TSH higher to reduce statistical risk of heart or bone problems, if the result of that dose of hormone is that you are unable to get off the sofa for day's on end. That will have a much greater risk to your bones and heart than any statistics will .