Glycosylated hemoglobin A2 (HbA₂) by electrophoresis

What This Test Measures

HbA₂ is one of several forms of hemoglobin that can exist in your blood. Normally, most hemoglobin is in the form of HbA₁c (hemoglobin A1c), which reflects average blood sugar levels over the past 2–3 months. HbA₂ is a distinct form that contains less sugar and is produced in people with certain genetic conditions, such as thalassemia. This test specifically quantifies HbA₂ levels using electrophoresis, a method that separates hemoglobin types based on their electrical charge.

Why It’s Done

Doctors may order HbA₂ testing to evaluate chronic blood sugar control in people with diabetes or to diagnose or monitor conditions like thalassemia, which affects how the body produces hemoglobin. It can also help distinguish between different types of hemoglobin disorders.

How It’s Performed

A small blood sample is drawn from a vein, usually in your arm. The sample is then processed and analyzed using electrophoresis, a technique that separates hemoglobin types by their electrical properties. The results indicate the proportion of HbA₂ relative to other hemoglobin forms.

What the Results Mean

HbA₂ results are typically expressed as a percentage of total hemoglobin. While reference ranges vary by lab, elevated levels may suggest genetic hemoglobin disorders (e.g., thalassemia), while normal levels are consistent with healthy blood sugar control in diabetes. Always discuss results with your healthcare provider for interpretation.