14/09/2025
HbA1c Test (Glycated Hemoglobin Test)
1. Objective
The objective of the HbA1c test was to measure the percentage of glycated hemoglobin in the blood to evaluate the average blood glucose level over the past 2–3 months.
It was mainly performed to monitor diabetes mellitus and assess long-term glycemic control.
2. Principle
The test was based on the principle that glucose in the blood binds irreversibly to hemoglobin in red blood cells, forming HbA1c.
Since red blood cells live about 120 days, the HbA1c value reflected the mean plasma glucose concentration during this period.
Detection was done by high-performance liquid chromatography (HPLC), immunoassay, or enzymatic assay methods.
3. Materials
• Patient’s venous blood sample (EDTA tube)
• Centrifuge
• HbA1c analyzer (HPLC, immunoassay machine, or enzymatic analyzer)
• Calibrators and controls
• Micropipettes and tips
4. Procedure (Laboratory Processing)
• Blood was collected in an EDTA tube and gently mixed to prevent clotting.
• The sample was either directly analyzed or processed through hemolysis to release hemoglobin.
• In HPLC method, hemoglobin fractions were separated based on charge differences, and HbA1c percentage was measured.
• In immunoassay/enzymatic methods, specific antibodies or enzymes reacted with HbA1c, and the reaction was quantified by analyzer.
• The HbA1c percentage was calculated and compared with reference values.
5. Result
• Normal: HbA1c < 5.7%
• Prediabetes: HbA1c 5.7–6.4%
• Diabetes: HbA1c ≥ 6.5%
• The results provided an average blood glucose estimate:
o 6% HbA1c ≈ 126 mg/dL average glucose
o 7% HbA1c ≈ 154 mg/dL
o 8% HbA1c ≈ 183 mg/dL (and so on)
6. Uses
• It was used to diagnose diabetes mellitus.
• It monitored long-term glycemic control in diabetic patients.
• It helped in adjusting treatment regimens for better management.
• It reduced reliance on frequent fasting or postprandial glucose measurements.
7. Conclusion
• The HbA1c test was a highly reliable marker for assessing long-term glucose control.
• It provided both diagnostic and prognostic value in diabetes management, making it one of the most widely used tests in clinical laboratories.
