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Thyroid UK
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Friends results. Different from NHS

I posted a week ago about my friend doubting the private finger prick tests reliability and how it concerned me.

She had an NHS test a few weeks ago just before 9am, her TSH was 3.6 (0.3-5.5). She did a private test Thursday with Medicheck and she has had her results today TSH 4.65 (02.-4.2) and FT4 16.04 (12-22).

The reason she doubted it was her TSH was 5.8 back in April with Medicheck, I told her things can improve and it doesn't always lead to full on hypothyroidism. She was very stressed earlier this year.

The thing is there is a whole point between the recent NHS and recent Medicheck results. I have told her that results differ depending on the range but my friend is sure that isn't the case, a result is a result. Is this right? I am interested to know ;-)


10 Replies

TSH fluctuates, even through the day, let alone over weeks. It's a snapshot. Unless you draw the blood at the same time on the same day and send them to the different labs you're not doing a comparison that has any meaning.

I think a TSH result is a result. The ranges are based on a different approach to treatment levels.


Thank you.

They are a few weeks apart and I said they can fluctuate. They are the same time of day both times but it can change slightly. It's only if like mine which rocketed from 7.5 to 9.28 in a few weeks it shows there may be a need for treatment. Her TSH is still above normal but GP won't acknowledge that.


Has she tested for antibodies?


Thank you :-)


If she took a TSH test every hour of the day it would be different each time. The TSH is highest early morning and varies throughout the day.


If her TSH rises it could be she needs an increase in her dose of hormones :)



The ref range is determined by the analysis machine used and the average result of a local population sample.



Local population may of course mean merely national population.



It will be a sample of the local population tested at the lab.


That can't be true of Blue Horizon and the other national private blood testers, they're not confined to a geographical area.



True, but it is the way most labs determine their ref range.


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