Hemoglobin in red blood cells binds with glucose to form glycosylated hemoglobin (HbA1c).

The HbA1c level indicates long‑term glucose control, unlike single blood sugar tests.

Clinical uses include:

Diagnosing diabetes mellitus.

Monitoring glycemic control in diabetic patients.

Assessing risk of diabetic complications (neuropathy, nephropathy, retinopathy).

The test does not require fasting and can be done at any time.

Often used alongside FBS, PPBS, and GTT for comprehensive evaluation.

Analyte: Percentage of glycosylated hemoglobin (HbA1c).

Normal Range (varies by lab):

< 5.7% → Normal

5.7–6.4% → Prediabetes (increased risk)

≥ 6.5% → Diabetes mellitus (confirmed on repeat testing)

Abnormal Findings:

High HbA1c: Indicates poor long‑term glycemic control, diabetes, or increased risk of complications.

Low HbA1c: May occur in conditions with reduced red cell lifespan (hemolytic anemia, recent blood loss).

Clinical Use:

Provides a long‑term measure of blood glucose control.

Helps guide treatment adjustments in diabetic patients.

Supports risk assessment for chronic diabetic complications.