Tracking all the numbers involved with diabetes care can get confusing.
In addition to measuring your blood glucose numbers, your doctor will also want to measure your hemoglobin A1C, which is your average blood sugar level for the previous two to three months. “It measures the percentage of hemoglobin — a protein in red blood cells that carries oxygen — that has been coated with sugar,” says Dr. Gregory Dodell, an assistant clinical professor of medicine, endocrinology, diabetes and bone disease at the Icahn School of Medicine at Mt. Sinai in New York.
If you have diabetes, you probably already measure your blood sugar at least once a day with a glucometer. However, your reading at any given time can be affected by several things, including what you recently ate, how well you slept, medications you’ve recently used and your level of physical activity.
[Read: 11 Tips for Testing Your Blood Sugar at Home.]
Your hemoglobin A1C results give a clearer understanding of how well your blood sugar is controlled over time. This is a crucial part of your care because if you measure your blood sugar at the same time each day, your readings may be very different compared with another time of the day.
Traditionally, you go to a lab for bloodwork, and the results reveal your hemoglobin A1C. There are also accurate at-home tests available for hemoglobin A1C. However, there are a couple of reasons you may not want to use them, says Evan Sisson, a certified diabetes educator and an associate professor at the Virginia Commonwealth University School of Pharmacy in Richmond.
First, when you have diabetes, you typically see your doctor every three months, and that’s also about how often you should get your hemoglobin A1C tested. Your doctor likely will want to see results from a lab. Additionally, if you do a hemoglobin A1C reading on your own and it’s higher than it should be, you’ll need to discuss the results anyway with your doctor. The tests can also be expensive, Sisson says.
“These tests have been demonstrated to be accurate. However, in order to get an overall assessment of diabetes, other lab tests should be performed in addition to the A1C. These include a cholesterol panel, kidney function, a screen for protein in the urine and liver function,” Dodell says.
Many doctors who treat people with diabetes recommend a goal hemoglobin A1C of 7 percent. A normal hemoglobin A1C for someone without diabetes is 5.7 percent or below. Prediabetes is indicated by a hemoglobin A1C of 5.7 to 6.4 percent. A hemoglobin A1C of 6.5 percent or above indicates diabetes.
[See: 6 Tips to Keep Diabetics Out of the Hospital.]
However, your goal A1C will vary for individual reasons. For example, in children with diabetes, doctors may aim for readings that are as low as reasonably possible, while in an older patient, the doctor and patient may agree to a goal reading above 7 percent, Sisson explains.
Although your hemoglobin A1C is usually connected to your blood sugar, there are some factors that can lower or raise your results. “People of African, Mediterranean or Southeast Asian descent or people with family members [with] sickle cell anemia or thalassemia [a blood disorder] are at risk for interference,” says Jessica Crandall, a certified diabetes educator and general manager at Denver Wellness and Nutrition Center–Sodexo. Crandall is also a spokesperson for the Academy of Nutrition and Dietetics. Iron deficiency and folate and vitamin B12 deficiency may also lead to a falsely higher A1C.
It’s good to know about the factors that may affect A1C readings, Dodell says. “Adjusting medication based solely on the A1C could result in hypoglycemia [low blood sugar] secondary to excessive medication or complications from diabetes due to undertreatment,” he says.
Crandall has seen patients with diabetes who believe an A1C reading of 8 percent is healthy and normal, but that reading actually indicates a high level of blood sugar. For this reason, you should discuss the right goal number for you with your doctor, and aim to sustain that goal. The more your A1C reading spikes higher than your goal, the greater chance that you’ll have health complications like kidney, nerve or eye damage.
Although hemoglobin A1C is the longtime reliable measurement of diabetes control, the actual number used is very different than the numbers you use when you measure your blood sugar. In other words, your A1C reading may be 7 percent, but your blood sugar reading produces numbers in the 100s (or higher). That can lead to confusion among patients who are used to tracking their blood sugar numbers. For this reason, the American Diabetes Association also addresses the importance of a number called estimated average glucose, or eAG. Your eAG is calculated based on your hemoglobin A1C. The eAG is thought to clear up that confusion.
“The estimated average glucose number is a way for the diabetes care team and the patient to have a common ground of communication,” Sisson says.
There are online resources to calculate your eAG, including this resource from the American Diabetes Association. Using the calculator, if your latest hemoglobin A1C reading is 7.2 percent, then your eAG is 160. You can also use the calculator in reverse. Say your eAG is 124; then your A1C reading is 5.9.
Generally speaking, every percentage point for A1C calculates to about another 30 points in your blood sugar measurement, Sisson says. So, an A1C of 6 percent is an average blood sugar of 125, while the 7 percent is 154, and so on.
[See: The 12 Best Diets to Prevent and Manage Diabetes.]
Doctors and certified diabetes educators may vary in their use of eAG with patients, but Sisson believes it’s an important number. “We’re talking about eAG all the time. Our job is to give advice and help patients to problem-solve at home,” he says. If patients need different ways to track their numbers, the eAG gives another tool to pinpoint blood sugar control problems so they can address them.
Both hemoglobin A1C and eAG are part of diabetes control, but they should be considered within your overall health picture. “If someone with diabetes has wide fluctuations in glucose value, with many highs and lows, their A1C may be at goal. However, they are not optimally controlled,” Dodell says. “Wide fluctuations in glucose values may have a long-term impact and certainly can affect quality of life.”
More from U.S. News
Which Medical Screenings Should You Have in 2017?
The 12 Best Heart-Healthy Diets
How Hemoglobin A1C and eAG Indicate Your Diabetes Control originally appeared on usnews.com
