Which test may be performed to assess the average plasma glucose level that an individual maintained during a previous 2- to 3-month period?

Which test may be performed to assess the average plasma glucose level that an individual maintained during a previous 2- to 3-month period?

• A. Plasma glucose
• B. Two-hour postprandial glucose
• C. Oral glucose tolerance
• D. Glycated hemoglobin

Answer: (D)

Glycated hemoglobin (A1c) is used to gauge the average blood glucose over the past two to three months. Glucose nonenzymatically attaches to hemoglobin in red blood cells as they circulate, and since red cells live about 120 days, the percentage of glycated hemoglobin reflects the overall level of glucose exposure during that period. In contrast, plasma glucose, postprandial glucose, and the oral glucose tolerance test capture glucose levels at a specific time or after a glucose load, not the integrated history of several weeks to months.

Glycated hemoglobin (A1c) is used to gauge the average blood glucose over the past two to three months. Glucose nonenzymatically attaches to hemoglobin in red blood cells as they circulate, and since red cells live about 120 days, the percentage of glycated hemoglobin reflects the overall level of glucose exposure during that period. In contrast, plasma glucose, postprandial glucose, and the oral glucose tolerance test capture glucose levels at a specific time or after a glucose load, not the integrated history of several weeks to months.