Blood Test Confusion??: Morning All, Just been... - Thyroid UK

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Blood Test Confusion??

Huddy1234 profile image
10 Replies

Morning All,

Just been for blood test this morning so took my last levothyroxiene 25mg on Sunday morning and only drank water before the test (as advised on here)

Lady taking blood said I should NOT have stopped my medication and it didn’t instruct me to fast?

I’m confused???

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Huddy1234
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10 Replies
SlowDragon profile image
SlowDragonAdministrator

You should have taken Levothyroxine yesterday morning, but not this morning.

Fasting is a patient to patient tip

But it won't be a problem. You are going to need dose increase regardless if only on 25mcg

Next time, just take dose as normal day before, as you take in mornings. Just delay the morning dose until after blood test.

Huddy1234 profile image
Huddy1234 in reply toSlowDragon

Hi SlowDragon,

Many thanks for your reply.

When you say patient to patent tip is that because it shows a more accurate reading on results?

SlowDragon profile image
SlowDragonAdministrator in reply toHuddy1234

There is an over reliance by medics on TSH. They often don't test or consider FT4 or FT3

Therefore it's essential to get highest TSH result possible, to prevent under medication

Knowledgeable endocrinologists will advise to not take Levothyroxine within 24 hours of blood test, as it increases FT4.

TSH is actually highest around 3am. Obviously not a practical time for a blood test. But it's highest generally in the morning

TSH daily variation

healthunlocked.com/thyroidu...

Patients have also learnt that TSH drops after eating. Hence the patient to patient tip to get tests as early as possible in morning and fasting

Also very important If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 3-5 days before any blood tests, as biotin can falsely affect test results

endo.confex.com/endo/2016en...

endocrinenews.endocrine.org...

Vast majority of GP's will be unaware of most of these points

On replacement thyroid hormones we need TSH around one and FT4 towards top of range and FT3 at least half way in range

Many GP's erroneously think anywhere in range for a TSH is good enough.

Median TSH graph

healthunlocked.com/thyroidu...

in reply toHuddy1234

Huddy1234 No it's not that it's more or less accurate per se, but it's a game of tactics many of us we feel we have to play with Drs! We want the TSH at its highest practically possible and FT3 & 4 at their lowest to encourage Drs to treat optimally. They often ignore or misinterpret results anyway so it's all a bit pointless but we have to do our best to optimise our treatment lol! So we keep our patient ploys to ourselves ..... My hospital has a walk in blood draw dept, seeing fasting patients before 9.00 and non-fasting after, so I always arrange to be there a little before 9.00 and if they've run out of fasting people I get seen sooner rather than later. But back in the day when I didn't have access to any such thing as an Internet, I took my Levo any old when, always slugged it down with coffee before during or after a meal, rarely bothered with blood tests (or seeing Drs) but if I did, had them whenever there was an appointment - and felt great ..... 😉

SlowDragon profile image
SlowDragonAdministrator

Please put this on a post of your own. Not hijack other people's posts

SeasideSusie profile image
SeasideSusieRemembering

Not sure why you discussed it with whoever took your blood. Patient to patient tips are just that, doctors, nurses, phlebotomists, will almost never agree so absolutely no point in mentioning it.

Huddy1234 profile image
Huddy1234 in reply toSeasideSusie

I discussed it because the phlebotomist asked me if I'd drunk any water as it was a early morning test!

I'm not aware of this "patient to patient" tips so just thought I'd ask on here as most people are very helpful with anything I've not been sure on.

shaws profile image
shawsAdministrator

I am assuming you didn't take your dose of levothyroxine on Monday which is not the right procedure.

What you do, if you take a morning dose is don't take the dose on the morning of the test but afterwards, you fast but can drink water. This, in effect, means your last dose was on Monday a.m.

The 'Lady' who drew your blood doesn't have hypothyroidism and besides many people who have hypothyroidism also have a high cholesterol level which a fasting test would also show an accurate result.

Huddy1234 profile image
Huddy1234 in reply toshaws

Hi Shaws

Many thanks for your advice - I will now do this for future blood tests.

The lady that drew my blood said she has hypothroidism and said I should always take the advice from the leaflet that comes with the medication.

It's just confusing when you hear different peoples advice.

shaws profile image
shawsAdministrator in reply toHuddy1234

She is obviously one of the very lucky ones for whom levothyroxine works fine (there are millions like that) but she is on a dose which has relieved all her clinical symptoms.

Most on this forum are struggling, either to get diagnosed or have an inefficient doctor/endocrinologist and who do not understand why they aren't improving.

When people were prescribed NDT (natural dessicated thyroid hormones) which was the only prescription for hypo since 1892 up until the late 50's.60's we were given increased doses until we had relief of all clinical symptoms and doses were around 200mcg to 400mcg so I have read. One of our doctors also stated that the doses they give nowadays are too low to benefit the patient who still complain.

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