June 26, 2014

The Difference - A1C and Blood Glucose Monitoring

I do not like doctors and other medical professions that tell people with type 2 diabetes that they don't need to test and that a quarterly A1c test is sufficient. In attempting to find a doctor, I could relate to, I have run the gambit or gauntlet of bad doctors. Two have said they were taking me off insulin and would not give me a reason for doing this. They just stated that I should be on oral medications as a person with type 2 diabetes. One even told me the first statement and that he would not prescribe testing supplies. Needless to say, they obviously were not up to date about diabetes.

This is one reason the blog from the Mayo Clinic really hit home. The author asked, “A1C or blood glucose monitoring: Which one is better? Neither. You need both measurements to ensure you have good diabetes management.” The author discusses both and importantly their differences.

The A1c test: For doctors, this is their bread and butter. It tells them how you are managing your diabetes. Most doctors want this test every 3 to 6 months. How often will often depend on how well you manage your blood glucose levels as a person with type 2 diabetes.

The goal standard set by the American Diabetes Association is for you to keep your A1c percentage at 7.0 or below. The American Association of Clinical Endocrinologists prefers the percentage to be 6.5 or below. The American Geriatrics Society recommends A1c levels of 7 percent or lower for healthy adults and less stringent levels for less healthy adults of 8 percent or lower.”

Now I don't agree with the upper limits that doctors recommend, but I do work to keep mine under the level set by the American Association of Clinical Endocrinologists. I will now get more technical by quoting from a blog by David Mendosa. “How much glycated hemoglobin we have in our blood depends first on the lifespan of our red blood cells. The “average lifespan is 120 days,” the book says, which is of course four months.

But the glycated hemoglobin in our blood is also “directly proportional to the concentration of glucose in our blood” and “represents integrated values for glucose over the preceding 8 to 12 weeks.” Most people seem to think that our levels at any time during this two to three month period are equal. But they aren’t.

“More recent values,” the book continues, “provide a larger contribution than earlier values.” How much more? “The plasma glucose in the preceding 1 month determines 50% of the HbA1C, whereas days 60 to 120 determine only 25%.” This is the key statement and the one that prompted me to change my testing strategy.”
Note: David tests his A1c on a monthly basis.” If you missed reading his blog, you may want to read it. I did leave out some page references that were not adding meaning.

Blood glucose metering: There are several terms that may be used - “blood glucose testing” or “BG testing.” Yes, metering is not a generally used term for blood glucose meter and test strips. Checking your blood glucose level helps you immediately and gives you information to aid in diabetes management decisions.

If you are not on insulin, blood glucose testing several times per week can tell you how well you are managing your diabetes. It will let you know if you need to make lifestyle changes or if you need to contact your doctor.

The two tests together can tell your doctor how well the long-range management has been for the last 120 days. Consider the A1c as a movie for the last 120 days and the blood glucose meter readings as a snap shot in time.

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