Blood test timing on T3: My understanding is the... - Thyroid UK

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Blood test timing on T3

Wired123 profile image
9 Replies

My understanding is the longer you leave it from having the T3 to having bloods done, the lower the T3 level.

Advice on this forum is to have bloods 8 hours after taking it. My previous Endo recommended 5 hours to see the peak.

My new private Endo says to take T3 at 7am and be tested at 9am. She’s now suggesting my T3 is too high… well no sh1t Sherlock!

I could of course use the 8 hour protocol on this forum, which will give a lower reading and may well lead to the doctor suggesting an increase in dosage.

Given that the reference range (I believe) includes all patients (those on replacement T3 and those who are “normal” population), is it even worth using that reference range as we are taking a tablet once or twice a day as opposed to healthy people whose bodies release a small amount of hormone throughout the day as required.

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Wired123 profile image
Wired123
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shaws profile image
shawsAdministrator

I've taken my once daily dose of T3 for sometime. I take it when I get up with one glass of water and wait an hour before eating. This is due to reading Dr John Lowe's papers and he was an Adviser to TUK before his accidental death.

When I'm having a blood test - at the earliest possible, fasting (I can drink water) I take T3 after blood draw with one full glass of water.

These are some links to Dr John Lowe who was also an expert in the use of T3 as he himself took it (in the middle of the night). He was also an Adviser to TUK. He was a doctor, researcher and expert in the use of T3.

helvella has collated the majority of Dr Lowe's papers and the following have links that may be helpful:-

dropbox.com/s/w7cjut689r1w1...

lisan1 profile image
lisan1 in reply toshaws

What would be the latest time that would be ok to have blood tests done?

shaws profile image
shawsAdministrator in reply tolisan1

It's best to have the earliest possible appointment for the blood draw for testing thyroid hormones - even if you make the appointment weeks ahead. You miss your a.m. dose and take it after the blood draw.

The reason for this is that the TSH is highest then and may prevent the doctor reducing our dose if he/she thinks we're on an optimum dose or may even think we're on too high a dose.

Very few GPs are knowledgeable about the TSH and may not even know that it is highest early a.m. or drops throughout the day.

So if we have an afternoon blood draw TSH will have reduced and GP may not give you an increase that you might need.

I make my appointment weeks ahead so that I get the earliest one.

lisan1 profile image
lisan1 in reply toshaws

Thanks! The problem is now that the Dr has reduced my meds for months and I ma desperate to increase but need to have a blood test before doing that and they don't have early am appointments for a month or two.

shaws profile image
shawsAdministrator in reply tolisan1

I'd speak to whoever makes the appointments and request - if someone wants to change their dates - that you'd take that person's appointment time.

The only other thing I can think of is that you get a private test from one of the labs. Just in case I will give you a link but make sure (if you decide to go ahead) that it is the earliest blood draw and fasting and make sure you are well-hydrated a couple of days before. If already taking thyroid hormones don't take till after the blood draw.

thyroiduk.org/?s=home+blood...

Wired123 profile image
Wired123

Is there any research on how T3 tablets release into blood stream over the 8 hours?

shaws profile image
shawsAdministrator in reply toWired123

According to Dr John Lowe (RIP) who was an expert in T3, and he also took T3 himself -in the middle of the night so that nothing interfered with its uptake.

Unfortunately for us, the patients, he died due to an accident and is sadly missed.

He stated - it's not verbatim but similar to what I read on his website:-

One daily dose of T3 taken with one glass of water saturates all of our T3 cells, and that one dose will then last for between one to three days by sending out 'waves'.

I trialled this myself - I took my daily dose on day one - none on day 2 and none on day t3. I felt fine and began again on day 4.

This following link is thanks to Helvella:-

dropbox.com/s/w7cjut689r1w1...

Wired123 profile image
Wired123 in reply toshaws

If this is the case then wouldn’t the advice to not take T3 for 8 hours prior to test be redundant?

I’m asking a genuine question.

Would be interesting to see blood levels of FT3 on an hourly basis after taking the tablet. I will see if someone has conducted this research and report back.

shaws profile image
shawsAdministrator in reply toWired123

When I am due for a blood test and as I take T3 alone I still get the earliest blood draw but wait until after it to take my dose of T3.

There's been no queries from Endo or GP but I know for a fact that one of the GPs is wrong in one of his explanation to me in the past when I told him that he was wrong in his assumption.

The most important question is "How do we feel?". If well we're on the right dose.

Keep in mind that before blood tests were introduced, all of the doctors and endocrinologists knew clinical symptoms and our dose of NDT (natural dessicated thyroid hormones) was gradually increased until patient felt well again..

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