This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
The Hemoglobin A1c level indicates the patient's level of glycemic control during the previous 
Select and explain. 
A. 1-2 months, B. 2-3 months, C. 3-4 months, D. 4-5 months
B: 2-3 months
Answer: B: 2-3 months 
Explanation: Measurement of glycated haemoglobin (HbA1c) is the standard method for assessing long-term glycemic control. When plasma glucose is consistently elevated, there is an increase in nonenzymatic glycation of haemoglobin; this alteration reflects the glycemic history over the previous 2-3 months because erythrocytes have an average lifespan of 120 days The glycemic level in the preceding month contributes about 50% to the HbA1c value.Harrison 19the pg: 2410