“Red light!” “Green light!” “Red light!”
We all remember playing that game as children. It was a fun way to pass the time. Personally, I always wanted to know what happened to the yellow light.
Oddly enough, as a doctor, I find myself asking the same question- where’s the yellow light???
The yellow light, of course, is a caution, a warning light- ‘slow down! the light is changing to red soon!’ While listening to a lecture about blood chemistry the other day, it occurred to me- there’s no yellow light in medicine.
When your doctor sends you for blood work and then reviews the results, your lab values are compared to a laboratory reference range. The limits of this range are viewed much like a cliff: you are either safely on top of the cliff or at the bottom. You’re either sick or you’re not. You need a prescription or you’re ‘perfectly healthy.’ Green light or Red light. What happened to the yellow light?
You don’t need to go to medical school to know that things are going wrong in the body before a full-blown disease develops. No one is perfectly healthy one day and suddenly wakes up with diabetes or heart disease the next. These diseases develop over time, after many months or even years of physiologic processes gone amuck. Its one of the reasons why we refer to them as chronic diseases. So again, where’s the yellow light to say ‘caution! if you don’t change some things, you’re going to develop diabetes or heart disease or fill-in-the-blank?’
This is the reason to use functional ranges instead of laboratory ranges. The functional ranges are based more on what the body needs to functional optimally, opposed to ‘not be sick.’
At this point, you may be asking yourself right now, ‘If functional ranges are based on what the body needs to functional optimally, then what the heck are those laboratory ranges based on?’
In general, laboratory ranges are based on the average value for all the people who have had a given test done in whatever particular time frame. Lab ranges vary from lab to lab and can even vary by region for the same lab. For instance, one common test is TSH, thyroid stimulating hormone. The laboratory range for this test is approximately .45 to 5.0. (To give you an idea, according to the American Endocrine Society, the functional range for TSH is 1.8- 3.0). Why is the lab range so much bigger? Well think about who is having their thyroid function tested- people with thyroid problems! So when your doctor says ‘your tests are normal’ what that really means is ‘your tests aren’t nearly as bad the other people who have had this test.’
Not exactly a good way to go about creating health! This is also why so many people don’t feel well, but aren’t getting answers as to why they feel so bad either.
So back to our yellow light. If we look at the blood tests a different way, with a functional range within a laboratory range, we can see our green, yellow and red lights. The green light is within the functional range; the yellow light is between the functional range and the laboratory range and the red light is of course, outside of the laboratory range.
Now with the yellow light we can begin to see areas of physiology that aren’t working quite right, but aren’t bad enough to be full-blown disease either. Even better then seeing them of course, is that we can begin to do something about them before they become full-blown disease. After all, isn’t that the point of healthcare?
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