By Doris Dickson for Body1
Reviewed by Dr. Mike Fuller
A hemoglobin A1C test is primarily used to measure average glucose over prolonged periods of time. The test measures the build up of glycated hemoglobin within the red blood cells. This measurement reflects the average level of glucose the cell has been exposed during its life cycle which is approximately 10-12 weeks.
What is a Hemoglobin A1C (HbA1c)?
Contrary to what many people believe, the test is not an average of your blood sugar as reflected on a home glucose monitor. Those tests are moments in time measured a number of times per day. Thus, an A1C is considered to be proportional to average blood glucose over the same period of time. This is reflective of the amount of sugar that sticks to the red blood cells 24 hours per day.
Because of the life cycle of the red blood cells, it is recommended that diabetics have this test every three months. You might consider choosing one lab and staying with it, since laboratory results may differ depending on the analytical technique. Therefore, it is easier to adjust your diabetes care if you are comparing apples to apples.
An example of an A1C conversion chart:
There are many conversion tables available. The charts show a correlation from an A1c to an average blood sugar level. The chart below is based on the conversion formula of Dr. Richard Bernstein.
What should your A1C be?
There are several answers to this question and the experts do not seem to agree.
According to Dr. Richard Bernstein a normal, healthy, thin, non-diabetic A1C will be within the range of 4.2-4.6. He also believes every diabetic can and should target, attain and sustain these normal levels.
The American Diabetes Association (ADA) states an A1C of less than 6.0 is normal and recommends an A1C less than 7.0 in diabetics.
The American College of Endocrinology (ACE) and the American Association of Clinical Endocrinologists (AACE) adopted a target A1C of less than 6.5 percent at their diabetes treatment consensus conference in 2001.
What do the experts agree on?
Although the diabetes experts disagree on the definition of a normal A1C and a target A1C for diabetics, they do agree that lowering A1C has been associated with a reduction in microvascular and neuropathic complications of diabetes and possibly macrovascular disease.
The ADA states "More stringent goals (i.e., a normal A1C less than 6 percent) should be considered in individual patients based on epidemiological analyses suggesting that there is no lower limit of A1C at which further lowering does not reduce the risk of complications…(particularly in those with type 1 diabetes)."
Last updated: 01-Jan-09