Hemoglobin A1C and Diabetes

Diabetes mellitus is a metabolic disorder which is characterized by an elevated blood sugar level over a prolonged period of time. Type 1 diabetes is often referred to as juvenile diabetes or insulin-dependent diabetes mellitus. There is loss of the insulin producing cells in the pancreatic islets called the beta cells. This leads to insulin deficiency. The cause is most often idiopathic or sometimes is immune-mediated where the T-cells lead an autoimmune attack on the beta cells. Type 1 diabetes is often times inherited and occurs mostly in children which is why it is sometimes referred to juvenile diabetes.

Type 2 diabetes mellitus is characterized by insulin resistance, which sometimes can be coupled by decreased synthesis of insulin. There is a defective response to insulin by the bodies different cells. Often a problem with the insulin receptors of these cells. Type 2 diabetes is a life-style problem and some genetic variability. Physical stress, poor diet, stress and excessive BMI are correlated with type 2 DM. In the early stages of type 2 DM it is manageable and the high blood sugar can be reversed by medications and be controlled. As it progresses it may come with complications similar to type 1 DM and treatment may need to be changed and monitored.

Hemoglobin is a protein found in the red blood cells in the body. For an in depth look at what hemoglobin is exactly take a look at the previous article written, titled “Hemoglobin”. Hemoglobin A1C, which is going to be talked about today refers to the glycolated hemoglobin within the body. Glycolated hemoglobin refers to glucose that is bound to the hemoglobin in the red cells.

Hemoglobin A1C is used to monitor diabetes and can tell doctors whether the dose of insulin is sufficient enough to bring the patients glucose to a healthy level and it can also diagnose diabetes. It gives a snapshot of glucose control over a period of 3-4 months. What happens with diabetes is that  glucose builds up in the blood. When too much glucose is present it begins binding to the hemoglobin within the red cells. This is called glycolated hemoglobin. It gives a fairly accurate analysis of glucose control over a period of 3-4 months because red cells live for 120 days.


The test is measured as a percentage. The percentage is pertaining to how much hemoglobin is saturated with glucose. The reference range is 4-5.6% although levels between 5.7% and 6.4% raise the risk of developing diabetes. A acceptable range for everyone is different when they have diabetes, but typically the individuals physician will work to keep the A1C level below 7%.  Its standard practice to order the hemoglobin A1C test every 3 months as a good way to monitor therapy and change doses, brands, etc. if needed. As the A1C levels rise or remain high it means that either the patient is non-compliant to their treatment regimen or that the treatment itself is not working and puts the patient at a higher risk of diabetic complications. Such complications include eye disease, heart disease, kidney disease, nerve damage and strokes.

Its important as a physician to recognize that certain conditions can alter the results of the test. Chronic anemias, kidney disease or specific blood disorders such as thalassemia can affect the results of the test and must be taken into consideration when using the A1C test to guide treatment.



One thought on “Hemoglobin A1C and Diabetes

  1. I’m a prime example of how life style changes can improve your A1C level. After changing my diet and increasing exercise, my level dropped and I no longer need to go for the 3 month check in. I was always mystified by how a drop of blood in that machine could tell what my level was, so thanks for explaining!


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