I have read that blood should ideally be taken as early as possible because TSH is highest first thing in the morning but does timing have any affect on T4 and T3 levels if you are not on any medication at all. I ask because I got my son tested with Blue Horizon as he many of the same symptoms as me, I was diagnosed underactive nearly 30 years ago. The GP did do a test last year but as his TSH was within range at 2.3 the labs will not test T4/T3 unless previously diagnosed.
Due to my very bad brain fog I totally forgot to wait until we had a day when we could collect the blood in the morning, plus he has difficulty getting out of bed even when he has an 7:00am shift at work. So we collected the blood at 3:30pm on Tuesday in time to catch the evening post. Results below:
CRP 0.40 <5.0 mg/L
Ferritin 97.7 30 - 400 ug/L
TSH 0.97 0.27 - 4.20 IU/L
T4 Total 134.3 64.5 - 142.0 nmol/L
Free T4 19.51 12 - 22 pmol/L
Free T3 5.99 3.1 - 6.8 pmol/L
Anti-Thyroidperoxidase abs 15.7 <34 kIU/L
Anti-Thyroglobulin Abs 20.2 <115 kU/L
Vitamin D (25 OH) L 19 Deficient <25 nmol/L
Insufficient 25 - 50
Consider reducing dose >175
Vitamin B12 540 Deficient <140 pmol/L
Insufficient 140 - 250
Consider reducing dose >725
Serum Folate 27.19 10.4 - 42.4 nmol/
The only obvious issue is his really low vitamin D levels which we expected as the sun causes his arms to blister so he wears long sleeves all year round. All the other results seem fine or did the time of day distort the results.
I will get round to posting my own results soon.
Any advice greatly appreciated