This is a test that measures the average glucose level of the patient over a period of about 2-3 months.

What happens is that in the blood, some glucose will bind to haemoglobin A. Once it's there, it's there for the life of that red blood cell-which is about 120 days total. The higher the amount of glucose at any time, the more will bind to the haem A. So the test records how much glucose is bound to your haem A cells.

Although levels of a positive result vary depend on who you are talking to, pretty much standard is that below 6 is considered healthy, and good.