Bloods fine but feel dreadful: Are u supposed to... - Thyroid UK

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Bloods fine but feel dreadful

Jonalicat profile image

Are u supposed to miss a dose before your blood test because I didn't will this give a wrong reading?

10 Replies
SeasideSusie profile image

Jonalicat Yes, you should leave 24 hours since your last dose of Levo, if you are taking T3 as well it's best to leave about 12 hours or so from last dose of T3. Blood should be drawn early morning, at the first appointment of the day, and fasting from the night before (water only). Breakfast and meds taken after the blood draw. Any deviation from this will give skewed results. Do you have your results yet?

Yes said normal

SeasideSusie profile image
SeasideSusieAdministrator in reply to Jonalicat

Well, normal doesn't actually mean anything. The ranges are quite wide and you could be normal just one point in from the bottom of the range or one point down from the top of the range - how you feel in each case would be vastly different.

Read and learn Jonalicat , you need to take control and you can only discuss things with your doctor if you understand all about it. Plough through some posts on here - topics on the right hand side in blue will link you to some apertaining to that subject. Also go to ThyroidUK's main website (this is their forum on Health Unlocked) and have a read through that.

First of all, always ask for a print out of your results. Assuming you are in the UK, you are legally entitled to them under the Data Protection Act 1998 so the surgery must give them to you although they may make a small charge for the printing. They do not need a reason for why you want them, but if they do ask all you have to say is 'For my own records'. And make sure that the reference ranges are with the results, eg

TSH 0.9 (0.27-4.2)

FT4 (18.5 (12-22)

If you obtain your results you can make a new post, giving them as I described, and members will comment and make any suggestions.

There could be a few reasons why you feel dreadful, ie undermedicated, not converting T4 to T3 properly, Hashimoto's (autoimmune thyroid disease) flare up, low levels of vitamins and minerals will means your thyroid hormone doesn't work properly.

You can ask your GP to do the following tests:




TPO antibodies

TG antibodies

They may not do all the thyroid tests, typically FT3 is rarely done and TG antibodies rarely done.

Vit D




All these vitamins and minerals need to be at optimal levels for thyroid hormone to work properly.

If your GP wont do them then we can point you in the right direction to get them done privately with a home fingerprick test.

The reason for leaving off thyroid meds before a test is because to get a diagnosis, or an increase in meds, TSH needs to be at it's highest level. TSH is naturally higher early morning and lower during the afternoon, hence the advice to have the earliest possible appointment. Leaving off meds also helps give a higher TSH, as does fasting because TSH drops after eating.

TSH level 1.5

SeasideSusie profile image
SeasideSusieAdministrator in reply to Jonalicat

Is that in answer to my question in my first reply ie Do you have your results yet? TSH on it's own isn't enough.

As mentioned in replies, this result is skewed because you took your levo before the test so it's worthless as far as you are concerned. As far as your GP is concerned he will be happy enough because it is in range.

However, if you're not feeling well and still have symptoms then you need the full range of tests which have already been mentioned.

Hi Jonalicat

I normally take my thyroid meds every morning but if im having a thyroid blood test i take them after the test which if you read other posts on here is what most people do, however, i used to take them before a blood test, i guess in order for the blood test to be of any benefit you need to be consistent and not change from taking them one time before a blood test and then not taking them the next time before the test. I'm sure there are scientific reasons for not taking your meds before a test that i've read on here but im not the best person to explain why but hopefully someone else will be along soon to help...

greygoose profile image
greygoose in reply to lc1973

Because you will only be measuring the dose you just took, and not what is normally in your blood. Also, your doctor will look at your elevated levels and want to reduce your dose!

AiryFairie profile image
AiryFairie in reply to greygoose

Why on earth didn't my GP (or the Phlebotomist) tell me this simple thing? Such a waste of time and resources... :(

greygoose profile image
greygoose in reply to AiryFairie

Because they have no idea!

Bloods say serum tsh level kw8414 1.5 mu/L 0.20-4.00mu/L

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