A child with type 1 diabetes who uses an insulin pump: which laboratory test verifies average blood glucose over the past 2 to 3 months?

A child with type 1 diabetes who uses an insulin pump: which laboratory test verifies average blood glucose over the past 2 to 3 months?

• A. Glycosylated hemoglobin
• B. Serum insulin level
• C. C-peptide
• D. Blood glucose fasting level

Answer: (A)

Glycosylated hemoglobin (HbA1c) is used because it reflects the average blood glucose level over the previous 2 to 3 months. This works because red blood cells live about 120 days, and the glucose that circulates in the blood binds to the hemoglobin inside those cells over their lifespan. As a result, HbA1c provides a long-term picture of glycemic control, which is especially useful for someone using an insulin pump where day-to-day readings can fluctuate with meals, activity, and pump adjustments. The other tests don’t give this extended view: serum insulin level indicates how much insulin is in the blood at one moment, C-peptide shows endogenous insulin production, and fasting blood glucose shows just the current level, not average control.

Glycosylated hemoglobin (HbA1c) is used because it reflects the average blood glucose level over the previous 2 to 3 months. This works because red blood cells live about 120 days, and the glucose that circulates in the blood binds to the hemoglobin inside those cells over their lifespan. As a result, HbA1c provides a long-term picture of glycemic control, which is especially useful for someone using an insulin pump where day-to-day readings can fluctuate with meals, activity, and pump adjustments. The other tests don’t give this extended view: serum insulin level indicates how much insulin is in the blood at one moment, C-peptide shows endogenous insulin production, and fasting blood glucose shows just the current level, not average control.