Hi,
Can someone explain why the ranges are different feom different providers. E.g.. the my NHS ranges are not the same as the private companys. And even some if the NHS ranges are.not the same.
So for example my T4 is 10.5 and in range with NHS but MMH range is 12-22. So does this mean my T4 would be out of range with MMH!
Also what does LH & FSH teat please?
TIA
No, it doesn't mean that. You have to interpret blood test results according to the given range, not anybody else's range. And to make it easier, we convert the result into percentages, making everything clearer. Handy percentage calculator:
The ranges are all different because they depend on the calibration of the machine used for the analysis, plus average levels from the population. But they're all pretty bogus, anyway. Have a look at this article:
helvella.blogspot.com/p/the...
At best they are only a rough guide. And you've perhaps noticed that ranges are only taken into consideration by doctors when it suits them. Otherwise, they're totally ignored!
Excellent question. I find the explanations given wholly unconvincing.
What's unconvincing about the ranges being linked to the calibration of the machines they use? Have you ever worked in a laboratory?
To your first question :
"The common assumption that laboratories can eliminate method differences by adjusting their reference intervals according to the method used has not been confirmed. RIs vary substantially between laboratories, and there is no clear correlation between the measurement procedure used and the suggested RIs. The most likely reasons are that laboratories use different sources of information and different study designs when establishing and validating their RIs". (c/o Tattybogle)
To the second:
Yes.
Best wishes
Well, it may not be perfect but it's the best we've got. The question was: why are the ranges different. Not are the ranges reliable. To that question the response would obviously be: no.
I said it was an excellent question (why are the ranges different). Then opinioned that the explanations were not convincing (imho).
At risk of prolonging things... Calibration is usually used to correct or adjust the results so that they are corrected against known standards or concentrations. But with thyroid results they seem to adjust the standard range rather than the result. This seems somewhat odd. Akin to adjusting the speed limit to account for the error in a speedometer!
Furthermore the standard range for any given lab then is composed of two elements firstly what they consider to be the true standard range plus an adjustment for their laboratory process. So it's a bit of a muddle.
Anyway, best wishes.
some stuff / and related posts here :
healthunlocked.com/thyroidu.... difference-in-reference-ranges-reading-matter-for-a-rainy-day-.
serum thyroid normal ranges
T3 and T4 ranges - VERY PUZZLED PATIENT
Lab has changed reference ranges 
Lab ranges 
