TSH and test time: I carried out a medichecks... - Thyroid UK

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TSH and test time

Mickeydooley profile image

I carried out a medichecks test in May. Usual timings etc. (24/12 hours prior). The test was done 8am. My TSH was 0.01. Had another test at the hospital clinic at 1.30pm a few weeks later. TSH then recorded 0.005. Could the timing of the appointment have made this much difference to my tsh levels?

33 Replies

Absolutely, yes. TSH is highest early morning, and lowest around midday.

Thanks GG. I knew they were highest in the morning but wasn’t sure if it would account for that big a drop. You’d think an experienced endo might take this into account before deciding to reduce someone’s meds.

SeasideSusie profile image
SeasideSusieAdministrator in reply to Mickeydooley

Also, don't forget that you'll get different results from different testing platforms even if the reference range is the same even if testing was done at the same time from the same blood draw.

You’d think an experienced endo might take this into account before deciding to reduce someone’s meds.

Endo probably doesn't reaise TSH differs at different times of the day, wouldn't surprise me at all 🙄

Really? So my medichecks results may bear no resemblance to the ones done at the hospital?

SeasideSusie profile image
SeasideSusieAdministrator in reply to Mickeydooley

You have to look at the ranges, if they are different then you have to work out percentage through range to compare:

thyroid.dopiaza.org/

then if they are different you have to take into account that they were done at different times on different platforms, they can't be compared exactly like for like.

Ranges are exactly the same and I always work out percentage through range so I can keep an eye on things and present to endo. I’ve learned a lot over the years from the experts here. Thank you.

Endos are experienced in diabetes, they don't care a jot about thyroid and operate on knee-jerk reactions rather than informed clinical decisions.

I saw a chart on this forum which showed the rise and fall of TSH during the course of the day but I can’t find it now using the search bar. Do you know how I can access it again please?

I don't, no. I keep saving it but never manage to find it again, either! lol I'll ask humanbean - help, humanbean! :D

Thanks

humanbean profile image
humanbean in reply to greygoose

Here it is :

healthunlocked.com/thyroidu...

I think it has been posted more than once but that is the link I have. Believe it or not it was posted in 2013.

Thank you. I’ve saved it now.

greygoose profile image
greygoose in reply to humanbean

Thank you HB. :)

To conventional medics there is no difference effectively in these TSH values. On both occasions they are very low and just being low without bothering with exactly why influences them to diagnose over-treatment which may or may not be the case. Also the precision of TSH assays is a bit poor in the far reaches of the test so some part of the difference is in the working of the test.

Thanks for the reply. I understand that they are both suppressed but my endo was making a big deal of the fact that my TSH had dropped even further than last time hence his decision to reduce my meds.

SlowDragon profile image
SlowDragonAdministrator in reply to Mickeydooley

Well the only thing he should be looking at is the Ft4 and Ft3 results….in conjunction with OPTIMAL vitamin levels

What vitamin supplements are you currently taking

When were vitamin levels last tested

Yes.

Folate 15.09 (>3.89).

Vit B12 >150 (37.5-150).

Vit D 160 (50-200)

Ferritin 273 (13-150)

Test done May 2022

SlowDragon profile image
SlowDragonAdministrator in reply to Mickeydooley

Presumably you supplement to maintain these as they are all good

I take vit d, vit c, zinc, magnesium and selenium. Also used to take b complex but was advised that my levels were too high so have reduced dose to once weekly for now.

Hope it’s ok to ask you a question please, as your B12 is 150 the same as mine, my Dr told me mine too high, has your Dr said anything about your result being too high? ( ranges are same by the way As yours) Thanks

I generally avoid my GP when I can. The doctor’s report from medichecks commented. I’m not an expert. It was above range so I decided to stop taking my supplement during the week and only take it at the weekend.

Comment

Thank you for sending the Medichecks comment it’s helpful

He has told me that the only thing he’s interested in is TSH. The thyroid hormones apparently aren’t important if your TSH is suppressed. 😂. My FT4 is currently below range (-6%) and FT3 is about 65% through range but apparently I’m over replaced!

SlowDragon profile image
SlowDragonAdministrator in reply to Mickeydooley

Run away from this endocrinologist as fast as possible

Many people on levothyroxine plus small dose of T3 need BOTH Ft4 and Ft3 at least 50-60% through range

We see this ALL THE TIME…..levothyroxine dose reduced far too much

How much levothyroxine are you currently taking

How much T3

Do you split T3 into 2 or 3 smaller doses spread through the day

Haha! I’d love to run away but I was referred to the clinic after months of trying to persuade my gp. It’s a clinic and I never see the same endo twice. If I ask to be discharged (I’ve been going for three years now and always the same argument) I’m afraid they’ll put me back to my gp who is desperate to take me off T3. It’s a fad he reckons!

I take 75mcg levo and 20mcg T3 in two doses. Tried 3 times a day but tbh was difficult timing wise for me

SlowDragon profile image
SlowDragonAdministrator in reply to Mickeydooley

Suggest you self source extra levothyroxine

Possibly…..Try reducing T3 by 5mcg and increase levothyroxine by 12.5mcg initially

You could try splitting levothyroxine as well as T3

Thanks very much for your help

I've never seen any study that observes the effect of time of day on TSH levels this low, or indeed a diurnal effect on TSH in people taking thyroid tablets although there probably is one.

I think it more likely the first assay could measure down to 0.01 and the second one down to 0.005. These numbers are so low I wouldn't assume they have any relevant difference from a clinical perspective.

Mickeydooley profile image
Mickeydooley in reply to jimh111

I see. Thanks. It appears to be particularly relevant to him unfortunately. 😩

jimh111 profile image
jimh111 in reply to Mickeydooley

He's being silly. Your dose is equivalent to 135 mcg levothyroxine which could just push TSH this low.

Suggest you see if you can be OK on a slightly lower dose, if not just leave a little more time between your liothyronine and having the blood taken. This will give an inaccurate result but get you through the hoops.

Mickeydooley profile image
Mickeydooley in reply to jimh111

Something I’ve considered. Thanks

jimh111 profile image
jimh111 in reply to Mickeydooley

I normally ask people not to do this but in your case you don't seem to have much choice.

Mickeydooley profile image
Mickeydooley in reply to jimh111

How sad we have to resort to this sort of devious behaviour just to get proper treatment. 🥲

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