Certified Dietary Manager (CDM) Practice Exam

What does glycosylated hemoglobin reflect?

1. The body's insulin sensitivity

2. The average blood glucose level over the past 2-3 months

3. Current glucose levels in the blood

4. Long-term dietary habits

The correct answer is: The average blood glucose level over the past 2-3 months

Glycosylated hemoglobin, commonly known as HbA1c, is a form of hemoglobin that is bound to glucose. Its primary role in clinical settings is to provide a measure of the average blood glucose levels over a period of two to three months. This is important because it reflects how well blood sugar levels have been controlled in individuals, particularly those with diabetes. When glucose is present in the bloodstream, it naturally binds to hemoglobin in red blood cells. Since red blood cells have a lifespan of approximately 120 days, the percentage of hemoglobin that is glycosylated can indicate the average blood sugar levels experienced by the person over the previous two to three months. A higher percentage of HbA1c indicates consistently high blood sugar levels, while a lower percentage suggests better management and control of blood glucose. The other choices, while related to aspects of diabetes management, do not directly reflect the function of glycosylated hemoglobin. Insulin sensitivity relates more to how effectively the body responds to insulin, current glucose levels measure snapshots of blood glucose at a specific moment rather than an averaged time frame, and long-term dietary habits might influence glucose levels but do not provide the direct measurement that HbA1c does. Thus,