Blood test thyroid medication : Hi All, I’ve had... - Thyroid UK

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Blood test thyroid medication


Hi All,

I’ve had Hashimotos for 20 years. Initially a doctor at University picked up my Tpo antibodies was 350 told me to keep monitoring as TSH was normal. Two years later it’s in the thousands and is gained 15kg. So I have been on Levothyroxine ever since. Same dose of 100mcg.

Last few years I’ve had issues with anaemia, VIT D levels and I didn’t know they were connected to my Hashimotos until I did some research recently.

This year has been particularly bad and now my TSH blood test was out and I’ve been told to double my medication on weekends then go back for more blood tests in January. I don’t know the actual results of the test.

I’m going to go gluten free in January as I’ve been feeling terrible for while and the scientific research says it may help.

I take my thyroxine medication in the morning an hour before eating. My question is whether you take your medication or not before a blood test. I’m getting conflicting advice that I should withhold the morning of a test others are saying take it. I normally take it.

12 Replies


I've asked nurses and doctors before, and they say you should take your meds as normal on the day of blood test as the point of the blood test is to know if the meds are enough/not enough for you.

I always ask my gp for a copy of my blood test or if it is a telephone consultation I ask them to tell me the numbers over the phone.

Hope that helps 😊

You don't take your levo till after the test. No food or drink after evening meal so water only till after the test. Take levo after test. Test as early as possible in morning ideally no later than nine

Blood levels peak about two hours after you take your levo. So, if you take it before your blood draw, all you will be testing is the dose you just took, not your normal circulating level. The peak will quickly reduce, and you will be left with much lower levels which may not be right for you. So, to get the normal circulating levels, we advise to leave a gap of 24 hours between your last dose of levo and the blood draw.

This is something doctors don't seem able to get their head around. Taking your levo just before the blood draw, during the peak, does not tell you if you are taking enough levo. Enough levo is having high enough levels of FT4 24 hours later. But, then, we all know that doctors and nurses understand very little about thyroid. And, many of them deliberately mislead you in order to give as little levo as possible, I'm pretty certain of that!

Always get a print-out of your results, because it's essential to get the ranges. Mistakes can be made over the phone. :)

I have just read on the Australian Thyroid Organisation website (I’m Aussie) that I should be having a blood test in the morning, fasting and not to take medication 24 hours before I get tested. So for 20 years I’ve been getting incorrect or false results. No wonder I feel like crap all the time and struggle to lose weight. I will be checking in with my doctor before my next test for the exact results and a serious chat about tests that are run etc. I feel let down by the medical profession that I haven’t been managed properly. It’s literally destroyed my life this disease and I didn’t realise how much of an effect it has had on my body and level of well-being. I always put my ailments down as my own fault in some way.

shawsAdministrator in reply to Blackkitty73

That's the rules we use in the UK amongst those who're hypo but it seems that the medical professionals have no idea of what to do.

"Let down by the medical profession! - Despite many visits to doctor, I was never advised (never mind advised - I had to diagnose myself when TSH was 100) and I doubt any other who has hypo are told by doctors anything about their condition as in these 'modern' times they no longer take into consideration the clinical symptoms and also know none. Once upon a time we were diagnosed upon symptoms alone and began a trial of NDT (natural dessicated thyroid hromones and has all the hormones a healthy gland would produce) until Big Pharma wanted a share and introduced blood tests and levothyroxine (T4 alone).

Doctors also seem to be completely unaware of the fact that the TSH is highest early a.m. and drops throughout the day which may mean they adjust your dose unnecessarily and make it even more difficult for patients who thought that doctors and endocrinologists were aware of how best to treat patients. Rarely do they ever check the FT4 and FT3's if patient is complaining as both need to be near the top of the ranges. They also seem to believe that a TSH of over 5 is fine, when we need it to be 1 or below. has been my saviour and you can be helped on this forum which has been a godsend to many left in the lurch.

Its not your fault - it is the professionals who're told to follow a certain path with regard to patients. Even though many do seem to recover on levothyroxine there is a section that cannot and I shall give you a couple of hints:-

All blood tests for thyroid hormones have to be the earliest possible, fasting (you can drink water) and allow a gap of 24 hours between last dose of levothyroxine and the test and take afterwards. Always get a print-out and make sure the ranges are also stated (for your own records and post if you have a query.

Some doctors only test the TSH and T4.

We need a Full Thyroid Function Test if symptomatic and it consists of:-

TSH, T4, T3, Free T4, Free T3 and thyroid antibodies.

It's never too late to try to improve our health and follow advice above and post. Also all vitamins/minerals have to be optimal, i.e. B12, Vit D, iron, ferritin and folate and are not always checked or are optimal. We need a good balance.

Blackkitty73 in reply to shaws

As mentioned in my original post I’ve been anaemic. Badly so this year go the point where I should have had an iron infusion as both stored and circulating were dangerously low. However I have rubbish veins so we had to resort to high doses at night of iron tablets. I’ve also had low Vitamin D, high blood pressure, and I suspect if tested I would have Vitamin B 12 deficiency. I take supplements at night now for all of these( as my Thyroxine medication is taken in the morning). I’m also medicated for depression as of this year and have moved jobs returning to casual basis because of stress and anxiety that was also affecting my health). I suspect all of this is Thyroid related but none have been linked to it, just dealt with as separate entities.

shawsAdministrator in reply to Blackkitty73

re 'depression' - which is awful but your GP should ensure that both your Free T4 and Free T3 are optimal as a low T3 (being the active hormone required in our millions of T3 receptor cells - brain and heart contain the most) both should be in the upper part of the ranges.

Few doctors request the 'frees' but are necessary sometimes when patient is still complaining. You may have to get a private test if GP wont test and I'll give a link - just in case and also follow the guidelines for blood draw, i.e. as early as possible, fasting (and allow a gap of 24 hours between last dose of hormones and the test and take afterwards). This allows the TSH to be at its highest as that's all doctors seem to take notice of.

Doctors, when we consult with them listen and take note of our symptoms, except for hypothyroidism as they only look at a blood test result and don't know any symptoms.

If you have a private test - blood draw should be at the earliest and fasting and a gap of 24 hours between last dose and test and take afterwards. Make sure you are well hydrated a couple of days before.

Doctors are apt to treat a 'symptom' i.e. depression, pain, etc etc as apart from hypo when we need symptoms to be taken as a whole, i.e. hypo.

Blackkitty73 in reply to shaws

Thanks Shaws for the links.

Unfortunately as I’m Aussie and in Australia I don’t think we have the option of private testing. All blood tests are by referral of GP. I don’t think we have any companies that will do tests without a doctor referral.

I will speak to my GP when I see him in a couple of weeks and ask for the tests. He may be accommodating and include them on the test if I request it specifically to be done. As I think I’ve been pretty complacent up until now and have just gone along with the normal testing regime but that has changed since I’ve been researching published papers in the last few weeks. I didn’t realise the new science and data that had been collated; especially in the last 5 years.

He knows I have a Science degree so he knows also my research is pretty solid. I’m just kicking myself for being so apathetic and not more proactive in what I want.

helvellaAdministrator in reply to Blackkitty73

As I am not in Australia, I might be missing something, but it looks to me as if private testing is available:

(That was just the first hit - it might be the worst or the best!)


Rather than the gross doubling of dose at weekends, how about a more subtle, and even approach? Have a look at this document:

I went for a search and found private blood tests but they are specific tests which my doctor will do already, so no need to pay for private in that regard. I will stick with double dose on weekend as apparently it’s a way to test for the reaction by the thyroid. If there is a positive response it may mean my medication needs to be increased; if no response then need to look at other possibilities.

I will stick with double dose on weekend as apparently it’s a way to test for the reaction by the thyroid.

What sort of reaction by the thyroid are you looking for? Seems highly unlikely to me that you thyroid is capable of any sort of a reaction after all these years. Did your doctor tell you that what you are taking is to repair the thyroid, or make it work better? If so, he really does know nothing at all. You are taking thyroid hormone replacement, replacing the hormone that your thyroid can no longer make. It doesn't cure, repair or change anything, just keeps you alive. It is not intended to illicit any kind of reaction from your thyroid, and there's no sort of reaction that your thyroid could possibly make that would tell you if you are on the right dose. I just cannot imagine what they've been telling you!

The way to know if you're on the right dose is a) how you feel, b) your blood test results. When on enough thyroid replacement, your TSH should be one or under, your FT4/3 should be somewhere in the upper third of the range, and all your symptoms should have resolved.

What helvella was suggesting is very sensible. It's best to avoid huge difference in daily dosing, such as doubling your dose at the weekends - which, quite frankly, is insane - and spread your weekly total more evenly across the week.

I feel let down by the medical profession that I haven’t been managed properly

I think all of us here have been let down by the medical profession to some degree or other, but it's not usually due to willful neglect, it's down to sheer ignorance. And, your doctor sounds worse than the average! They just do not know about these things. They have no idea how to treat or how to interpret blood test results. They just have no knowledge of how the thyroid works, or what it does. They do not understand hormones or how to handle them. It's a universal problem, I'm afraid.

If helvella didn't reply to you, it's probably because he didn't see that you'd replied to him. On this forum, you need to click on the blue 'reply' button underneath a comment, for the author to be notified that you have replied. :)

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