In this thread thyroiduk.healthunlocked.co... someone suggested that the normal range is supposed to be set using patients who don't suffer thyroid issues.
I worry about the ranges as it's my understanding that the labs set the ranges using tests that have been sent to them at the request of doctors - ie tests taken from patients who are ill. I've never heard of a well patient being asked to supply a test for reference purposes.
Anyhow, just read this article chriskresser.com/5-thyroid-... where the writer says:
"Who goes to labs to get tested? Sick people. If a lab creates its “normal” range based on test results from sick people, is that really a normal range? Does that tell us anything about what the range should be for health?"
How the ranges are set in the US is also mentioned in this vide. thyroiduk.healthunlocked.co...
One day I must ask my GP how the ranges are set in the UK. I'll bet he doesn't know.