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Normal Hormone Levels
What can we understand from lab results that indicate normal levels?
What is normal? When I first began to prescribe bioidentical hormones, I decided to measure patients’ levels both before and during therapy. When ordering serum levels from commercial laboratories, I was immediately struck by reports displaying a wide amount of normal ranges. I contacted the chemists and asked how their ranges were decided. In general, the laboratory ran the tests on a group of patients. Normal was defined as those values that stood within two standard deviations on each side of the mean. Sometimes, sub-groups were broken out. As an example, DHEA and DHEA-S are different for men and women and both decline with age. The normal ranges are defined separately for each gender and decade of life. Even so, normal does not necessarily mean healthy. While attending medical school in the 60s, normal systolic blood pressure was 100+ the patient’s age. Although this may have been normal or at least common and usual, it was not healthy. When healthy range levels were redefined for blood pressure, independent of age, suddenly millions of Americans went from being healthy (or at least normal) to sick. Much of the same thing has happened with cholesterol measurement. The companies that make lipid lowering drugs (and the physicians that lecture for them) have pushed normal LDL cholesterol lower and lower. It used to be around 130 and was age dependent. Now it sits below 100 for everyone. I asked the laboratories if they could tell me what the mean and median numbers were for each value, along with the distribution curve. I wanted to determine if healthy patients were clustered around certain values and if outliers were skewed out at one end or another. I was told that this data was not available. I realized that I was going to have to perform a lot of measurement testing to find out what patients looked and felt like at various levels. |