2 blood test results, which one is correct

[Svete]

dear All

Please could I ask for your opinions about the following

I had a blood test for TSH, at 11am,no levothyroxine in the morning, test shows 1.33.

two weeks later my consultant requested a blood test as well,so levothyroxine in the morning, as I didn't know I was going to have a test, 5.30 pm, the test came back 0.30

I'm wondering do I need to repeat a test or which of these results are correct .

my levothyroxine dose 0.75 mg per day,5 days per week and 100mg twice per week.a

appreciate your advices.

Svete

[greygoose]

Well, they're both correct. For the time of day, and considering natural fluctuation of the TSH.

TSH is highest before 9 am, then dips down to its lowest point around midday. Then, it starts to rise again until midnight.

But, even two tests done at the same time of day, weeks apart, are likely to be different. There are so many variables that affect the TSH.

And, the difference between your two results really isn't that significant.

If I were you, in future, I would refuse all blood tests for thyroid after 9 am. No-one can force you to have one if you don't want it. That way you will be as consistant as possible for comparison, and get the highest TSH of the day.

[Svete in reply to greygoose]

Thank you very much!

[greygoose in reply to Svete]

You're welcome.

[SeasideSusie Remembering]

Svete

Basically they are both correct for the circumstances in which they were done.

TSH is highest early morning and lowers throughout the day - see first graph here and you'll see how much higher TSH is at 9am then 5.30pm:

thyroidpatients.ca/2020/07/...

Taking your Levo wont affect TSH, it just affects FT4 level, but the fact that you had eaten may mean TSH may have been affected as certain foods and drink can affect TSH.

But TSH is the least important of all the thyroid tests once diagnosed and on thyroid hormone replacement, it's not a thyroid hormone, it's a pituitary hormone, the thyroid hormones are T4 and T3 and it's the FT4 and FT3 test results which tell us our thyroid status, unfortunately most doctors don't know or understand this.

[Svete in reply to SeasideSusie]

Thank you very much!

[Greengirl68]

what do you do for high TSH value 14.65 if not thyroid?

[SlowDragon Administrator in reply to Greengirl68]

Please write a new post of your own

If TSH is over 5 you are hypothyroid