What is HbA1c?

HbA1c

How will you Define HbA1c?

• HbA1c measures the average blood glucose level over 3 months period.
• It is reported as a % or an estimated average glucose.
• Hemoglobin has the sugar residue attached to the Red blood cells. HbA1c is the major fraction (80% ) of glycated hemoglobin.
• HbA1c is also called:
  1. Glycosylated hemoglobin.
  2. Glycohemoglobin.
  3. Glycated protein

Discuss the pathophysiology of HbA1c?

1. Glycated hemoglobin is essentially irreversible, and its concentration depends upon the following:
   1. The lifespan of the RBCs is an average of 120 days.
   2. Blood glucose concentration.
2. The rate of the formation of glycated hemoglobin is directly proportional to the concentration of the blood glucose level.
3. Glycated hemoglobin concentration represents the integrated values for glucose over the preceding 6 to 8 weeks.
4. Day-to-day changes do not influence glycated hemoglobin in the blood glucose level.
5. This process of glycosylation occurs when the RBCs are exposed to blood glucose.
6. Initially, there is a bond between the RBCs, and glucose is labile but later on becomes stable.

HbA1c glycosylation

HbA1c formation

HbA1c structure

What is normal HbA1c?

• In case of no diabetes = 5.6% or less
• Prediabetic                   = 5.7 to 6.4%
• Diabetics                       = 6.5 or more

How will you explain the Diabetic goal of HbA1c?

• Good diabetic control = <7%.
• Fair diabetic control = 8% to 9% (another reference = 6% to 8%).
• Poor diabetic control = >9%  (another reference = >8%).

What are the goals of diabetes mellitus patients?

1. Newly diagnosed patients should try to keep HbA1c below 7%.
   1. In such patients, the average glucose level is 154 mg/dL.
2. When HbA1c is around 8%, then the average glucose is 183 mg/dL.
3. HbA1c of 9% will have an average glucose level of 212 mg/dL.
4. HbA1c of 10% will have average glucose of 240 mg/dL.
5. Ideally, one should try to keep the HbA1c level around 7%.