Glycosylated Hb% (HbA1c)

Function

Hemoglobin A1c (HbA1c) measures the percentage of hemoglobin that has glucose attached to it. Because red blood cells live for approximately 120 days, this test provides a weighted average of blood glucose levels over the preceding 2 to 3 months, making it superior to daily finger-prick tests for long-term monitoring.

Why it is Ordered

It is the gold standard for diagnosing Prediabetes and Type 2 Diabetes. It is also the primary tool for monitoring glycemic control in known diabetics. Unlike a fasting glucose test, HbA1c does not require fasting and is not affected by short-term lifestyle changes (like a single high-sugar meal the night before).

Associated Conditions

• Diabetes Mellitus: Diagnosed at an HbA1c of 6.5% or higher.
• Prediabetes: HbA1c between 5.7% and 6.4%, indicating a high risk of progression to diabetes.
• Metabolic Syndrome: Often associated with elevated HbA1c and insulin resistance.
• Cardiovascular Disease: Chronic hyperglycemia (high A1c) is a major risk factor for heart attacks and strokes.

Therapeutic Targets

For most adults with diabetes, a target of <7% is recommended to prevent complications like retinopathy (eye damage) or nephropathy (kidney damage).