Timing of blood test

[Mothebear]

I know 8 am, no thyroxine, no vit B for a week etc before and before 8am is best for a blood test (I have Hashimoto’s). What am I compromising as my appointment is 10.45, in terms of my blood test looking at the effect of a slight lowering of my thyroxine. I don’t want to have it lowered any further, but also would prefer not to have to battle my endocrinologist.

Thanks for any insight.

[SeasideSusie Remembering]

Mothebear

If you check out the first graph in this link you will see the circadian rhythm of a healthy thyroid:

thyroidpatients.ca/2020/07/...

You will see that the highest TSH level is around midnight to approx 4am then reduces, the next highest point is at 9am then reduces throughout the day and starts to climb again from about 7-8pm.

So your 10.45am appointment is going to give you a lower TSH than doing the test at 9am when TSH is highest. However, this will not affect your FT4 level. It's the timing of the last dose of Levo that affects the FT4 level and to get a measure of your normal circulating amount of that we suggest last dose of Levo is 24 hours before the blood draw - too close to the test and you'll get a false high FT4 and any longer gives a false low FT4 level.

[Mothebear in reply to SeasideSusie]

Thank you.

[SlowDragon Administrator]

FT4 21.3 range 12 - 22

TSH 0.05 range 0.27 - 42

Free T3 4.3 range 3.1 -6.8

Vit B12 active 112 range 25-165

Ferritin 132 range 13-150

Folate >20 range >2.9

Vit D 100 range 50-200

Results from 6 months ago show poor conversion

FT3: 4.3 pmol/l (Range 3.1 - 6.8)

Ft3 only 32.43% through range

If endocrinologist wants to reduce dose levothyroxine, you need to insist on T3 prescribed alongside levothyroxine

[Mothebear in reply to SlowDragon]

Thank you. I dropped from 100mg a day to 4 days of 100mg and 3 days of 75mg. My brother has the gene that shows he needs T3. I don’t feel I have the extreme symptoms he had, weight battle all his life, muscle pains, brain fog etc. and he is massively improved since being given it, but not before he threatened to go to Dignitas he was struggling so much - and had to get the gene test done privately. But GP accepted evidence and referred him to endocrinologist!

[SlowDragon Administrator in reply to Mothebear]

Suggest you get Dio2 gene test

Likely you have it as well

thyroiduk.org/deiodinase-2-...

regeneruslabs.com/products/...

[Mothebear in reply to SlowDragon]

Thank you. I have been thinking I should too!