HbA1c (what it measures) is best described as:

HbA1c (what it measures) is best described as:

• A. Percentage of haemoglobin bound to glucose, reflects average blood glucose over 2-3 months
• B. Rate of red blood cell production
• C. Fasting insulin level
• D. Blood glucose at a single timepoint

Answer: (A)

HbA1c measures the percentage of hemoglobin that has glucose attached to it, reflecting how much glucose has been around the red blood cells over time. Because red blood cells live about 120 days, HbA1c provides an estimate of average blood glucose over roughly two to three months rather than a single moment. This makes it a useful marker for long-term glucose control and for diagnosing diabetes. It is not a measure of red blood cell production, nor a fasting insulin level, nor a glucose value at one time point.

HbA1c measures the percentage of hemoglobin that has glucose attached to it, reflecting how much glucose has been around the red blood cells over time. Because red blood cells live about 120 days, HbA1c provides an estimate of average blood glucose over roughly two to three months rather than a single moment. This makes it a useful marker for long-term glucose control and for diagnosing diabetes. It is not a measure of red blood cell production, nor a fasting insulin level, nor a glucose value at one time point.