Thyroid Recovery Series: Your lab ranges are too wide

Why do you still have symptoms if your lab tests are normal?  Why do you continue to suffer with extreme fatigue, memory loss, hair thinning, etc.. when your doctor has told you that all of your lab tests are “within normal range?”  The answer could be because the lab tests are extremely broad.  The ranges vary WIDELY! There are two main types of ranges in the field of blood chemistry analysis: a pathological range, and a functional range (functional ranges have been determined by The Endocrine Society ( The pathological range is used to diagnose disease; the functional range is used to assess risk for disease, before the disease develops. The references that are provided with laboratory test results are referred to as “the pathological range,” because if the test results are out of range, it usually indicates potential for pathology or disease. Let talk about your  thyroid.  Your doctor usually orders only one thyroid test, the TSH (Thyroid Stimulating Hormone).  If you are lucky, maybe he has ordered a couple more.  From your MD’s perspective, if your TSH level is within that very wide lab range of .35 to 5.0, you’re normal–there’s nothing wrong with you!  BUT—and this is a HUGE “BUT”—the OPTIMAL LEVEL or “functional level” for TSH is much more narrow: 1.8 to 3.0 (according to the Endocrine Society).  So you could still be “normal” in the medical doctor’s eyes but abnormal in the functional or optimal range. You may have been told your lab tests are “normal” so- you are normal. But, lab ranges are based on who’s been in the lab in the past year. Who goes to labs usually? Are they basing your ranges on a “normal” healthy person or the “normal” sick person?


Leave a Comment

Next post: