I think that the "normal" levels depend on which labs the tests are sent to. My son has had 2 endos and they sent the blood to different labs; the normal ranges were different. Also, I read what normal ranges were on a web site referencing med. tests and they were very different from what Jack's dr. said the ranges were for his tests. (The web site was one of the ones to the left of this message board. Sorry I can' t remember which one) I also agree with the previous posts - my son's dr.s have all said to keep the big picture in mind and not focus on just one test result. And one last thing . . . I have heard that the test results can vary if the person is stressed. If my son was really worked up during his draw, his endo considers that his level will appear a little higher than they really are.