Stacy Wiegman, PharmD
Pharmacy Specialist
Results of an A1C test and a blood glucose check don't always match up. The A1C test measures your average blood sugar levels over a 120-day period (the lifespan of a red blood cell). But a blood glucose check measures your blood sugar at a single moment. If your blood sugar levels were high last week, and you adjusted your diabetes treatment plan so that your blood sugar returned to normal, the A1C result may still be high, because it includes the high blood sugar levels from the previous week.
The A1C test measures the percentage of glycated hemoglobin in your blood. Glycated hemoglobin is created when molecules of hemoglobin (the oxygen-carrying protein in your blood) attach to molecules of glucose (the sugar in your blood). The more sugar you have in your blood, the higher your percentage of glycated hemoglobin.
Your blood glucose levels are probably based on your premeal blood glucose levels. While this usually works well, it does not take into account the level of your blood glucose after you eat. It may be that your blood glucose is rising unexpectedly after your meal because you are either not taking enough insulin or not taking insulin far enough ahead of eating your meal. To see if this is the reason that your A1C is high, measure your blood glucose 2 hours after breakfast, lunch, and dinner for several days (in addition to your premeal blood glucose levels). Blood sugar that is more than 200 mg/dl 2 hours after a meal is too high. In addition, your blood glucose may be high throughout the night, when you are asleep. To find out, wake yourself up at 4:00 a.m. several times during the week to check your blood glucose. At 4:00 a.m., blood glucose that is higher than 150 mg/dl is too high. Continue to check your blood glucose 2 hours after meals and in the middle of the night once a month to be certain that you are not having unexpected high blood glucose levels at these times.
Continue Learning about Diabetes
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Diabetes
Diabetes mellitus (MEL-ih-tus), often referred to as diabetes, is characterized by high blood glucose (sugar) levels that result from the body’s inability to produce enough insulin and/or effectively utilize the insulin. Diabetes is a serious, life-long condition and the sixth leading cause of death in the United States. Diabetes is a disorder of metabolism (the body's way of digesting food and converting it into energy). There are three forms of diabetes. Type 1 diabetes is an autoimmune disease that accounts for five- to 10-percent of all diagnosed cases of diabetes. Type 2 diabetes may account for 90- to 95-percent of all diagnosed cases. The third type of diabetes occurs in pregnancy and is referred to as gestational diabetes. Left untreated, gestational diabetes can cause health issues for pregnant women and their babies. People with diabetes can take preventive steps to control this disease and decrease the risk of further complications.
