Glycated hemoglobin (HbA1c) reflects glucose bound to hemoglobin within which cell?

Correct answer: A. Red blood cells (erythrocytes)

• A. CORRECT. HbA1c measures the fraction of hemoglobin within ERYTHROCYTES that has been non-enzymatically glycated. Because the red cell lifespan is roughly 120 days, HbA1c reflects average glycemia over the preceding 2–3 months. This is also why conditions that shorten red cell survival — hemolytic anemia, sickle cell disease, recent transfusion, chronic kidney disease — make HbA1c falsely LOW and unreliable.
• B. Leukocytes contain no hemoglobin.
• C. Platelets do not carry hemoglobin and live only 7–10 days.
• D. Hepatocytes are not the site of hemoglobin glycation; the liver's role is measured by other markers such as fructosamine (albumin-based, 2–3 weeks).

Note: Anything that shortens red cell life falsely lowers A1c. In those patients use fructosamine or serial glucose instead.