AskNadia: What’s The Science Behind The A1C Test

Dear Nadia,



Dear RAS,

The A1C sometimes referred to as the Hemoglobin A1C, glycosylated hemoglobin, glycated Hemoglobin and HbA1C measures your husband’s  average glucose from 60 to 90 days. When your husband tests his blood sugars with a blood glucose meter, this only tells him what his glucose level is at that moment in time. It does not accurately reflect the highs and lows he experiences nor does it reflect the direction his glucose could be trending.

Blood cells form and die within a 90 day period. The A1C test records the memory in the red blood cells, giving us an average reading that correlates with a percentage.

People that don’t have diabetes have an average A1C of 4 to 6%. A 9 percent A1C means your husband’s blood  sugars are averaging around 212 milligrams per deciliter and millimoles per liter

Sometimes you can get a false  A1C high if you have anemia, an iron deficiency or a blood transfusion. The percentage can also vary depending on where you get your A1C tested. It’s best to use the same lab.

The American Diabetes Association recommends taking your A1C test twice a year. Their target A1C is 7 percent.

The American Association of Clinical Endocrinologists (AACE) feel that this number is not aggressive enough because it means the average blood sugar is running around 154 milligrams per deciliter and millimoles per liter. They recommend an A1C of 6.5 percent or less which gives you an average blood sugar above 126 milligrams per deciliter and millimoles per liter.

Your husband’s  A1C reading will play a significant role in preventing diabetes complications. Maintaining a lower A1C is generally more desirable. There are some exception to the rule which is why your husband needs to speak to his healthcare professional to set a targeted A1C that is right for him.

The Science Behind The A1C

The A1C measures hemoglobin;  the red blood cells that carry protein. The hemoglobin molecules have four sub units known as a1, a2, b1 and b2. These sub units also have four heme molecules. Oxygen molecules bind to the center of these four sub unit heme molecules, allowing oxygen to be delivered to the cells of the body.

Glycated hemoglobin is when sugar binds to protein. If the hemoglobin is high, it limits the oxygen delivery which is when vascular complications can occur.

Setting a suitable A1C for your husband require a visit to his physician. Hopefully you can support him in making an appointment sooner than later.

You might also be interested in reading these A1C articles on diabetes




Mayo Clinic


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