Timing of Medichecks Bloodtest

[catpurple7]

Hi all, i've bought the advanced thyroid bloodtest from medichecks and just wondered if anyone knows if it is ok to do the test at 5am or is this too early? i start work at 6am and so thats the only time i have to do it.

[SeasideSusie Remembering]

catpurple7

Take a look at the first graph in this link, it shows the circadian rhythm of TSH. You will see it's highest at midnight, then about 4am, then there's a gradual decline. Testing around 5am will give you a higher TSH than any other time during the daytime:

thyroidpatients.ca/2020/07/...

[catpurple7 in reply to SeasideSusie]

Thanks SeasideSusie, is that ok then?

[SeasideSusie Remembering in reply to catpurple7]

If you are looking for the highest possible TSH then yes it's fine.

Don't forget the last dose of Levo should be 24 hours before the test, water only before the blood draw.

[raglansleeve in reply to SeasideSusie]

I've oftened wondered about this too. I live on a schedule of going to bed at 4:00a.m. and rising at 11:00a.m. so I always looked at that circadian chart and adjusted it by about 4 hours since I figured that most people get up at about 7:00a.m. If the OP gets up at 4 or 5a.m. for work every day, would her rhythms not be unique too? I'm not sure if I'm explaining myself well here, but basically, doesn't a circadian rhythm match a person's sleep cycles differently if they don't rise and go to bed a "normal" hours?

[SeasideSusie Remembering in reply to raglansleeve]

raglansleeve

I'm afraid I can't answer your question. Why not contact ThyroidPatientsCA to ask them, then let us know what they say:

thyroidpatients.ca/home/con...

[raglansleeve in reply to SeasideSusie]

I'll do that. Thanks!

[tattybogle in reply to raglansleeve]

I know what you mean.. i don't think anyone has done much 'Thyroid based' research on permanent night-shifts/ circadian rhythm . but i do vaguely remember reading something that gave me the impression that just going to bed at the 'opposite time' is not enough to move the timing of the circadian rhythm ..... ? too many other influences of daylight / temperature etc etc , going on ?... but perhaps it might be worth looking for information about other pituitary hormones / night-shift worker .... as the pituitary is responsible for the early morning TSH rise , which then in turn drives the fT4 to rise a short while later ... there might be more research into some of the 'other' pituitary hormones .. which would also be influenced by a change in timing of circadian rhythm affecting permanent night shift workers .

[raglansleeve in reply to tattybogle]

Very good point about the sunlight and night-shift workers (as long as they're on nights permanently) would make an ideal cohort to study.

[SlowDragon Administrator]

Do private testing Monday or Tuesday morning and post back straight away

If testing iron levels, stop iron supplements a week before test

If taking any supplements that contain biotin stop these 5-7 days before test as biotin can falsely affect test results

[catpurple7 in reply to SlowDragon]

Thanks SlowDragon, i planned on doing the test at 5am and then posting it on my way to work.

Not really taking any supplements atm (which is probably one reason why i feel so crappy)