RE: Concerning not taking thyroxine before blood tests.

[Guest guest]

You should dose according to how you FEEL not numbers on a computer screen!!

> I have finally arranged an appointment with my GP to ask for the battery of

blood tests that is recommended by this forum and came to consider once again

the question of whether or not to take my thyroxine as normal before the tests.

[Guest guest]

--- In thyroid treatment , "SkewedHalo" <skewedhalo@...> > > This very clearly says that taking thyroxine before a blood test will affect the T4 levels. It does NOT say that it would affect TSH or T3 levels. Are we sure that thyroxine should not be taken before these tests even when our doctors tell us we should take the dose as normal?

Hi Sharon,On the basis that your doctor has ordered more than just a TSH and if you want an accurate FT 4 figure, then do not take your Levothyroxine on the morning of the blood draw... Take your dose after the blood draw.You are correct in saying that taking or omitting your Levo will not affect your TSH figure. The TSH takes a few weeks to move - but taking your Levo will influence the FT4 as well as FT3 and elevate both figures (unless you had a conversion problem, in which case it would only elevate the FT4).Best wishes

[Guest guest]

What you quoted is from the testimony given by Professor

Weetman when he gave evidence as 'expert witness' at the General Medical

Council during Dr Skinner's Hearing.

The evidence shows that you should not take ANY thyroid hormone

replacement on the morning your blood is drawn to test your thyroid function.

You have the answer below for levothyroxine, and for T3, the same applies but

for a different reason. T3 has a very short half life of 2 days in humans, and the

effect from taking T3 starts to diminish after 6 to 8 hours. This is why it is

recommended you take T3, either synthetic or natural, in split doses, i.e. half

in the morning when you wake and the other half around 2.00/3.00p.m. However,

T3 peaks in the blood around 2 to 3 hours after taking it, so testing your

blood after taking it would give a flawed result. We have often heard that

doctors will stop a patient from taking T3 because of high levels and putting

them back on to levothyroxine, which often makes them quite ill again. It's

really common sense. However, having said all that, it is pretty useless doing

thyroid function tests when a patient is taking T3 and a doctor should titrate

their dose according to their symptoms.

TSH is the last result to change. Stopping thyroid hormone the

day before the test will make no difference to your TSH.

Sadly, most of us opted to become members of thyroid support

groups because we were left suffering under the NHS and needed to find answers

as to why we were/are being refused either a diagnosis or refused a choice of

treatment. This is because doctors have been badly taught at medical school and

they know little to nothing about the functioning of the thyroid gland. Therefore,

we should use our common sense and do our own research to find the facts, which

is what we are trying to do here. Our doctor is not 'god' over thyroid

matters. If they were, we would not be here.

Sheila

The evidence quoted to not take it is as follows:

" The problem with using free T4 measurements if a patient is taking

thyroxine is that the level fluctuate after taking thyroxine treatment.

Therefore, within the few hours after ingestion there can be a ten or fifteen

per cent level difference in level compared to twelve to twenty four hours

after ingestion. The second problem which is frequently encountered by

endocrinologists is that the patients may not adhere to their treatment very

strictly and may remember to take a tablet before a blood test which will give

them normal T4 levels and might have omitted their tablets over the preceding

weeks. Because of the sensitivity of the pituitary that can be identified by

raised TSH but a normal free T4. Therefore, TSH, because it is measuring a

response of the body, in this case the pituitary gland, it is by far the best

measure of the nature and degree of thyroid hormone replacement. "

This very clearly says that taking thyroxine before a blood test will affect

the T4 levels. It does NOT say that it would affect TSH or T3 levels. Are we

sure that thyroxine should not be taken before these tests even when our

doctors tell us we should take the dose as normal?

Thanks,

Sharon

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[Guest guest]

Thank you both and Sheila for your explanations. If I am telling a

doctor that they have given me wrong information then I want to be able to

understand and explain why it is wrong. I now feel armed for battle!

Sharon

>

> What you quoted is from the testimony given by Professor Weetman

> when he gave evidence as 'expert witness' at the General Medical Council

> during Dr Skinner's Hearing.