I know what the advice is from here (no levo for 24hrs, last liothyronine 8-12 hrs before blood draw) and I have followed this for my blood tests so far.
When I saw my endo recently however, he specifically said I should take both as normal around 6/7am before my next blood test at 930am.
I don’t know what to do - isn’t that going to make my FT4 and FT3 seem higher than they really are, and possibly make my TSH lower than it really would be?
I feel like that’s going to produce a result which will make him feel justified in reducing doses which I think is what he wants to do, despite me still feeling rubbish and FT3/4 being below range (TSH is normal).
TIA!
Written by
cazzaleo
To view profiles and participate in discussions please or .
Personally if every other test you have taken for results has meant delaying taking until afterwards then that is what I would do. Maybe either don't admit it or just don't confirm deny either way.
That’s how I feel. I’m thinking maybe I’ll take them a bit further away from the test (the night before) and then say I’ve done what he requested if he asks? Maybe it’ll be obvious to him that that’s what I’ve done though?
Fact is Endos, even the better ones, are behind and not caught up to the science and patients. You want accurate results, his advice would do the exact opposite.
He mentioned last time about not wanting my TSH to go too low because of potential osteoporosis and atrial fibrillation- will have to go armed with the research/evidence against that that I’ve seen on here!
Unless he sees you taking then not taking your doses 24 hours apart, clinically there will be no indications that you haven't had your regular dose that morning.
When he asked at my last appt re when I took them before my last blood tests I told him what I’d done, as I didn’t see any reason not too. So although my dose will have changed between the two blood tests, he is no aware that I may not take the dose right before the blood draw 😬
This is exactly what we're afraid of when we tell people it's a patient-to-patient tip about leaving the 24/12 hours gaps, and not to tell them. It was pretty obvious that if they knew, they would take steps to counter it. The last thing they want to do is have to increase people's doses, rather than lower them!
But, to be exact, leaving that gap will not affect your TSH. It doesn't change that fast. Taking your hormone before the test will just give you false high Frees, because all you will be testing is the dose you just took, not what is normally circulating in your blood. And, you need to always do your tests the same way, or you can't compare them.
The level of the TSH depends on the time of day the blood is drawn. It is highest early in the morning, and drops throughout the day, and after eating. And, as doctors only tend to look at the TSH, we want it as high as possible.
Did you not ask him why he wanted you to take your hormone that close to the blood draw? I'd love to know what excuse he'd give.
I had no idea it wasn’t something I should have told him 🤦♀️
Thanks for clarifying about the TSH, at least that’s something, as I’ll have the blood taken fairly early and will fast beforehand.
He said that the blood tests don’t show him anything significant that he can use to inform how I’m doing/what to do with dosing unless I’ve taken my doses that morning.
Oh what rubbish! He knows nothing at all about thyroid. He's just making excuses.
Of course you didn't know, I wasn't blaming you, just a warning for anyone reading. It would seem the obvious thing to do, to share our knowledge with them. But they don't want to know the truth, they just want to use things like that to their own ends.
Oh, all sorts of reasons, I imagine. I did hear one once, somewhere, saying thyroid wasn't sexy, diabetes is. Well, whatever floats your boat! But, one of the problems is that in their formative years as doctors, they are exposed far more to diabetes than to thyroid. Diabetes patients end up in hospital with their diabetes far more often than hypos with their hypothyroidism. Perhaps this leads them to believe that thyroid is far less serious. Darling Dr Weetabix, or whatever his name was, even said 'hypothyroidism is easy to diagnose, easy to treat'. Just goes to show how much he knows! But, what with one thing and another, I think they get the impression that thyroid problems just don't need a specialist - anybody can do it!
Sorry to sound so negative regarding the wisdom and expertise of Endos ( I'm onto my 6th in 2 years) but really most utter poppycock and on a more positive note we really need to learn how to 'manage' them to our own advantage and if we fail, relegate them to room 101.
They just want us to remain sick .............Period. I'm convinced mine has a death wish on all his patients. Tell him you feel better ( chance would be a fine thing) and he instantly scrapes resourcefulness together ...................... To try and make me feel ill! It is a very sad state of affairs when you are home alone, apart from this Heaven sent forum.
(This post is 4 yrs old) But... in answer to your question ...., the long half life of levo provides a base level for testing fT4 this is true , BUT the absorption of a Levo tablet from the gut gives a short lasting peak on top of that baseline which occurs from approx 2-6 hours after the tablet is taken. (variable depending on speed of the individual's gut function).
this 'peak from absorption' is what we want to avoid as it is briefly quite a bit higher than the base level..... by 12 hours after the tablet, the level of fT4 is almost back down at the base level , but 24 hours is probably better for consistency , hence 24hrs is what is recommended.
Thanks. I don't know why old posts are appearing in my emails. I only started taking 25mcg levo about 10 days ago and I actually feel worse, more achy although I do have hashimotos and neuropathy but the nausea is getting to me. I'm thinking of cutting them in half as there is a score line. I feel I can't carry on much longer like this, had high hopes of feeling better and losing some weight even though I never eat very much but always healthy. My tsh has been over 8 on and off since last September and I'm a stone over weight which is not like me at all.
feeling worse when started on a very low dose is not unusual . halving the dose is unlikely to fix this, because the problem is probably caused by the fact that the dose is low .
25mcg is just enough to lower your TSH a bit .. which then signals your own thyroid to have a bit of a rest .. so you then make less T4 from your own thyroid .
As your levo dose is increased things should improve.
very simplified example:
lets assume you need '100' to feel well.
your own thyroid is struggling so it can only make 75 . you then add 25 from levo .. so for a few days you get 100 .. but then your TSH lowers in response to the increase , meaning your own thyroid then only produces 25 ... so then you get 50 in total .. which is less than you had before you added the 25 from Levo .
As levo dose is increased this will balance out, until you get 100 from your own thyroid +levo.
It would be best to start a new post of your own detailing what brand of levo you take etc .and asking for advice ... as some brands of levo do make people feel unwell, but even of the brand is not problem , it is not unusual to feel worse before you feel better when starting on a low dose .. but discussing ' you ' on this old post from somebody else will end up confusing everyone
Thanks so much, I had no idea the thyroid was so complicated. I was virtually ignored for 5 years with primary hyperparathyroidism so my Osteoporosis deteriorated further 12 percent.The GP had to get permission from head honcho in the endo dept for 25mcg as they were concerned I could go hyper. This happened to me 6 years ago, i didn't know what was happening to me, not did GP's or a private endo who was an idiot . I had no knowledge of thyroid just the parathyroid. It was only a surgeon in London understood the 13 weeks of hell which he said was thyroid storm and then he discovered I had hashimotos.
Gosh I've just been reading your life story, sounds awful. I'm now wondering about TEVA and splitting the dose as you have done. I am elderly admittedly but a few months ago I was building a shed in the garden, now I can barely vacuum of mop and feel like I'm dying. The neuropathy is spreading it feels, I already have a T5 compression fracture from osteoporosis and horrendous headaches everyday from when a chiro cracked my neck July 2020. I paid a huge sum I. March 2020 and had a parathyroidectomy and thought this was the new start for me. It was until I had a reaction to the covid vax nearly a year ago.I'm thinking of investing in one of those pemf mats but do expensive and only guaranteed for 12 months.
Realistically you need to allow several months to find the right dose of levo and then once settled on the right dose improvements should happen. But the first few months are usually like a game of snakes and ladders .ie. .... 'nothing' (or 'worse' )for a week or so , then somewhat better for a week or so then worse again for a week or so , then a blood test.. then a dose increase .. repeat.. but hopefully each time the 'better' stays better for longer.
25mcg is not meant to be the dose you stay on, its just mean to be a more gradual introduction to the usual 50mcg starting dose. used when people already have heart issues , or are over a certain age. because they don't want to dump a load of extra T4 all at once onto the heart .
Give it a few more weeks as the first 2/3 weeks are always going to be weird after any dose change , but if nausea continues to be a problem it's worth asking for a different brand of levo to try .. a lot of people don't get on well with Teva. ( but some prefer it )
Regarding risk of low TSH it’s based on the assumption that thyroid hormone are also high, which is not always the case. TSH can be only interpreted in light of the FT4/FT3 levels, rather than in isolation.
“The study found that patients with very high (>4.0mU/l) or suppressed (≤0.03mU/l) TSH levels more frequently suffered from heart disease, abnormal heartbeat patterns and bone fractures compared to patients whose TSH levels are in the normal range (0.4-4.0 mU/l). Patients who had a slightly low TSH level (0.04-0.4mU/l) did not have an increased risk of contracting any of these conditions.”
I don't think they consciously assume that, they're just parroting something they heard, but if you try to pin them down, they have no explanation as to why a low TSH would affect bones and heart.
I would take no notice, and lie or prevaricate if necessary. You don't want to be measuring the dose you just took, regardless of what the endo says. It probably won't affect TSH, but will make thyroid hormones too high.
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
Do I take thyroxine before I have blood test 
Endo nurse says I must take levo before my tests!!!
Before I do my last test before GP treats me. Adrenal Q
