Which statement is true about HbA1c values?

Which statement is true about HbA1c values?

• A. HbA1c of 5.5% is diagnostic of diabetes.
• B. HbA1c between 5.7% and 6.4% indicates prediabetes.
• C. HbA1c above 6.5% does not aid in diagnosing diabetes.
• D. HbA1c is a direct measure of peak plasma glucose.

Answer: (B)

HbA1c reflects the average blood glucose over roughly the last 2–3 months, because it measures the amount of glucose that has irreversibly attached to hemoglobin as red blood cells circulate. Using this long-term view, guidelines classify risk categories: a level between 5.7% and 6.4% signals prediabetes, indicating elevated risk for developing diabetes and cardiovascular issues, but not diagnostic diabetes. A value at or above 6.5% is used to diagnose diabetes, typically confirmed with a repeat test or supported by symptoms. A value like 5.5% is considered normal or near-normal and does not indicate diabetes. And HbA1c is not a direct measure of peak plasma glucose; it does not capture a single high spike but rather the overall average exposure to glucose over months.

HbA1c reflects the average blood glucose over roughly the last 2–3 months, because it measures the amount of glucose that has irreversibly attached to hemoglobin as red blood cells circulate. Using this long-term view, guidelines classify risk categories: a level between 5.7% and 6.4% signals prediabetes, indicating elevated risk for developing diabetes and cardiovascular issues, but not diagnostic diabetes. A value at or above 6.5% is used to diagnose diabetes, typically confirmed with a repeat test or supported by symptoms. A value like 5.5% is considered normal or near-normal and does not indicate diabetes. And HbA1c is not a direct measure of peak plasma glucose; it does not capture a single high spike but rather the overall average exposure to glucose over months.