Hemoglobin A1c measures:

✓ Correct Answer: Option B

HbA1c: reflects average glycemia over 2-3 months (RBC lifespan ~120 days). <5.7% normal, 5.7-6.4% prediabetes, ≥6.5% diabetes. Target <7% for most diabetics (ADA). Falsely altered by hemoglobinopathies.