Which statement about HbA1c is true?

Which statement about HbA1c is true?

• A. Reflects average blood glucose over 2-3 months
• B. Indicates acute glycemic change
• C. Measures fasting glucose
• D. Is unaffected by red blood cell turnover

Answer: (A)

HbA1c measures how much hemoglobin becomes glycated as red blood cells circulate. Since red blood cells live about 120 days, the glycated fraction reflects average blood glucose over roughly 2–3 months, with more weight from the recent weeks as older cells fall out of circulation. This is why it’s used to gauge chronic glycemia rather than daily swings. It doesn’t capture acute changes or fasting events, and it can be influenced by conditions that alter red blood cell turnover (for example, anemia or recent transfusions), which can affect the reading even if average glucose is the same.

HbA1c measures how much hemoglobin becomes glycated as red blood cells circulate. Since red blood cells live about 120 days, the glycated fraction reflects average blood glucose over roughly 2–3 months, with more weight from the recent weeks as older cells fall out of circulation. This is why it’s used to gauge chronic glycemia rather than daily swings. It doesn’t capture acute changes or fasting events, and it can be influenced by conditions that alter red blood cell turnover (for example, anemia or recent transfusions), which can affect the reading even if average glucose is the same.