How Blood Glucose Levels Relate to Diabetes and the Importance of the A1c Blood Test
- Fasting/pre-meal: between 80 and 130 mg/dL
- One to two hours after meal: below 180 mg/dL
A1c Blood Test
by Audrey Demmitt, R.N. updated 11/22The A1c blood test, also known as glycated hemoglobin, hemoglobin A1c, and HbA1c, is the primary tool used to diagnose diabetes and pre-diabetes and to monitor blood glucose control in people with type 1 and type 2 diabetes. This test enables health care providers to diagnose diabetes and treat it before complications occur and to diagnose pre-diabetes to prevent or delay the development of type 2 diabetes. Below are the established A1c levels used to diagnose diabetes and pre-diabetes:
|Normal||below 5.7 percent|
|Pre-diabetes||5.7 to 6.4 percent|
|Diabetes||6.5 percent or above|
How Does the A1c Compare to Other Blood Glucose Tests?There are several other traditional blood glucose tests that are used to diagnose and manage diabetes: the fasting and random blood glucose tests, the glucose tolerance test, and the self-monitoring home glucose test. These can be thought of as snapshots, measuring the blood sugar level in a moment of time or day to day. Normal blood glucose levels range from 80-100mg/dL (milligrams per deciliter), fluctuating throughout the day in response to food, activity, medication, illness, and stress. Daily readings are interpreted in the short term to monitor blood sugar changes. It is helpful to do daily testing and record the values to reveal patterns and responses so that you can take corrective actions and make adjustments to your daily care plan. In contrast, A1c is a long-term average of blood glucose levels and gives a “big picture” perspective on how well you are doing in controlling daily blood sugars. It can be useful in evaluating the overall success of the treatment plan, your daily efforts, and the efficacy of medications.
How Does the A1c Relate to My Daily Blood Sugars?Your A1c can be converted to a number that is expressed in the same terms as your daily blood glucose readings. This is called “estimated average glucose” or eAG. For example, an A1c of 7% is equivalent to an estimated average glucose (eAG) of 154 mg/dL, reflecting blood sugars that may have ranged between 180 and 140 mg/dL over the past three months. The A1c/eAG is not the same as the average blood glucose you may see on your meter, since it is an average of all the blood sugar levels – not just the ones you may have recorded on your meter. The average blood glucose reported on your meter is likely to be lower than your actual A1c/eAG. Maintaining blood sugars as close to normal range as possible is the goal to reduce risks and complications of diabetes. When daily blood sugars are kept in optimal range, the corresponding A1c will also be optimal. Below is a table with conversions of A1c levels to eAG.
|A1c in percent||eAG in mg/dL|