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Lab Tests/lab reference ranges


Dr. Prater, I'm confused about lab reference ranges varying between labs. I had a fasting blood glucose test done at Labcorp and their reference range is 69-99 and my reading was 110. I recently had it retested at Quest labs and their reference range is 65-99. I don't have the results yet, but would a 110 reading at Quest equal a 110 reading at Labcorp, even with the range difference? Or if I got a 100 reading at Quest, would it translate
to a different number at Labcorp because of that 4 point difference or does it make no difference? I'm not good at math and can't seem to figure this out. Thanks

Lab reference ranges can vary slightly because they themselves are calculated from the average from what is run through the lab for each given test. Your reading of 110 is universal for either of those labs as it is an absolute value and not a percentage. Functional lab ranges are different, and are looking for your optimal health, for which fasting glucose should be between 80-90. Much smaller range. Too low suggests one thing, too high suggests other things. Hopefully this was helpful. Any other questions please let me know.

Dr. Kalli Prater

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Dr.Kalli Prater


I can answer questions about routine lab work, functional lab ranges for optimal health, what lab tests should be considered and when you need to seek a second opinion. I can also answer questions about specialty testing like: stool testing, hormone testing, and saliva testing.


I run lab tests in my office as a functional medicine practitioner and use functional lab ranges looking for patient's optimal health not their disease. I review many charts and labs and look at trends through the years as well as current symptoms. Usually I find more things on labs that the traditional doctor that correlate to the patient's concerns/issues.

American Chiropractic Association

Doctor of Chiropractic Medicine, B.S. in sports Medicine.

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