Thyroid Reference Ranges

Normal lab values for Thyroid Stimulating Hormone-(which I disdain) are:

20 yrs of age or older 0.20-4.50 mIU/L


This range is much too wide, resulting in a high percentage of those tested to be thyroid insufficient, but not considered as such because of the invalidity of the reference range. I much prefer to use the reference range from the Nat’l Academy of Clinical Biochemists based on NHANES III (National Health & Nutrition Examination Survey) which is:

0.3-1.5 mIU/L       Normal
>1.5 mIU/L           Suspect Thyroid Insufficiency
>2.0 mIU/L           Almost certain Thyroid Insufficiency (the higher the number is over 2.0, the more likely is the probability of thyroid insufficiency)

I prefer this reference range over the laboratory reference range because it makes the test a MUCH more valid test for thyroid function. I have always considered the TSH (thyroid stimulating hormone) test to be a poor prognosticator of thyroid function, if not downright worthless. Apparently the Nat’l Academy of Clinical Biochemists agreed with me and created this much more valid reference range based on a national health survey completed early in the 21st century.

Don’t expect your medical doctor to concur.

Fred M. Bogan, DC