Hi, I have an under active thyroid, have been on thyroxin for 42 years, have just had another blood test and it read 0.05mlU/L (0.40-4.00) LL, my Doctor wants to see me again, he thinks I might be bordering on Hoshimoto disease, from my previous blood test and was looking
at lowering my dosage of 150 milligrams a day, do you think he's right,
Welcome to the forum! I am assuming we are talking TSH and that is the only test result been given?
You mention an earlier test, was that the only result given then?
I can understand your doctor freaking out because of the low figure but that's because they do not because they should! Once on medication the TSH reading doesn't tell us a great deal as your body is getting what it needs from elsewhere
Can you let us know if you have any other figures to look at and also what your last one was and we may then be able to tell you some more and why your doctor is thinking along those lines!
Although we need a lot more information, basically, how do you feel? My TSH is even lower and I feel great - so I don't care what my TSH is. If you feel normal, don't let any one move things around on you, you will only relapse into hypo eventually. If your doc thinks you are bordering on Hashimotos, let him measure your antibodies then s/he can graduate from thinking about it to knowing about it. Now, if you feel ill, that's another matter. Get a full spectrum of thyroid hormonal tests so that you can see what is too low. 150mcg's is a normal/high dose (I assume we are talking Levo, which is pure T4) so it might be that you are not converting that T4 to T3 so get your FT3 and FT4 measured so that you can find out.
Also, read up as much as you can about hypothyroidism, you have to stay a couple of steps ahead of your doc because you can stay in sub-par health for a long time if someone else is trying to sort you out, only you know if you are on the right dose or the right medication.
Don't worry about him saying you might have Hashimoto's, you may have had it for years if all they've ever tested is TSH. They will test for antibodies to confirm diagnosis. Can't see why they'd want to drop your meds unless you said you'd got palpitations, always hot and can't keep weight on.
If you are feeling well then there is no need to touch your medication.
I would insist on a referral to an endocrinologist rather than have your GP experiment on you.
He or she is out of their league here.
If you feel good, insist on keeping the meds stable, if you don't, demand to see a specialist, that's my advice.
The short answer is that the doctor is wrong.Without testing FT3 and FT4 which they rarely do once diagnosed and on levo it is impossible to say. Do you feel any different ? Do not let him lower the dose without further tests and especially if you feel OK .Antibodies have to be tested to see if you have Hashimotos which is one cause of underactive thyroid and you may have had it for donkeys years.
Hi heav,
I have always been on thyroxine since birth (55 years). My TSH has been as low as 0.09 and I have tested positive for antibodies but no mention of Hasimoto's though. I was on 250 mcg of thyroxine at the time and 20 mcg of lithyronine. However, my thyroxine dose has now been reduced to 200 mcg and 20 mcg of lithyronine, which I say is my natural dose and my last TSH level was 0.54. I don't really go on TSH levels as my reading will be naturally suppressed anyway as my thyroid does not work at all. It would be interesting to see what your T4 and T3 ranges are though. I think your GP is jumping the gun a little too soon and should at least do some more tests before reducing your dose.
The reason I think he is most probably thinking that if they reduce your dose, your TSH which is your own thyroid hormone, will rise, he to me, is implying that you are over prescribed on T4 and that is why he wants to reduce your dose. But if your gland is not working at all, then your TSH will also be naturally suppressed, so can not be an accurate reading. Have you got your T4 and T3 results?
Hope this makes sense?
Take care 
TSH provides little info, and certainly no info about whether or not you have Hashi's. If you feel well, with no trace of hyperthyroid symptoms, then I suggest you stay at 150 micrograms. But if you really want to know what is going on, then you should demand a full panel TSH/FT3/FT4/rT3/TPOAb/TGBAb, and bring the results back here for review. Dosing in accordance with FT3 & FT4 readings is the surest way to know thyroid hormone replacement is correct, from a lab test point of view. Which is less important than how you feel.
Thanks everyone for responding to plight. the results of my blood test that I posted was from my last blood test. due to go back to see him next week. I feel fine, used to be on 300mg of Levothyroxine for over 10years and since they have reduced it they can't seem to get my dosage right, they first reduced it to 250 mg, then to 100mg then back up to 200 and now at the moment 150mg. they reduced it because they said I became hyper active. they have never given or told me results before, and silly me had never asked, but this is my body and I know it better the anyone else. yes will ask to see a specialist. thanks heaps for all your replies and will keep you all posted.
just been back to the doctor today
he wants me to try 125mg of synthroid instead of 150mg levo .
I asked him to reefer me to a endocrinologist, but said I woulnd.t be able to see him/her as my tsh is to high and need to get it down.
he has agreed to another blood test in six weeks time of being on a slightly lower dosage to test creatine T.S.H HbA1c Ferritin B12/folate and vit D also for antibodies, which he forgot to get tested last blood test. I thought he had printed out my prvious test , but when I got home and looked at it , it was 6th nov 2015 . on the same dosage back then it read
Free T4 18pmoi/l (10-24
tsh 0.62 miu/l (0.40-4.00
Free t3 3.5pmoi/l (2.5-6.0
Follow up call with Endocrinologist 
Did I mess up my blood tests?
Signing up for online medical records
I may have messed up my bloods? 
