Challenges in HbA1c Analysis and Reporting in Patients with Variant Hemoglobins

Area of Science:

• Clinical Chemistry
• Hematology
• Diabetology

Background:

• Hemoglobin A1c (HbA1c) is a key indicator of average blood glucose levels.
• Genetic hemoglobin variants, particularly Hemoglobin E (HbE), are common in Southeast Asia and can interfere with HbA1c measurement accuracy.
• Accurate HbA1c monitoring is crucial for managing diabetes.

Purpose of the Study:

• To compare HbA1c measurements using High-Performance Liquid Chromatography (HPLC) and Turbidimetric Inhibition Immunoassay (TINIA) in diabetic patients with hemoglobin variants, specifically HbE.
• To evaluate the reliability of both methods in the presence of HbE.
• To identify potential strategies for improving HbA1c testing in populations with high hemoglobin variant prevalence.

Main Methods:

• Analysis of HbA1c levels in 7595 diabetic patients using both HPLC and TINIA methods.
• Identification of patients with undetectable or below-normal HbA1c levels by HPLC.
• Confirmation of hemoglobin variants (HbE) using alkaline electrophoresis.
• Correlation analysis of HbA1c results with fasting blood sugar levels and Mean Corpuscular Volume (MCV).

Main Results:

• 0.95% of patients showed undetectable or below-normal HbA1c by HPLC.
• 34 cases had undetectable HbA1c by HPLC but reportable levels by TINIA.
• 38 cases had below-reportable range HbA1c by HPLC but normal/higher levels by TINIA.
• TINIA showed strong correlation with fasting blood sugar (r²=0.75) in affected cases, unlike HPLC (r=0.24).
• Mean MCV was lower in the study group (73.65±10.44) compared to controls (83.80±7.48), suggesting HbE presence.

Conclusions:

• HbE variants significantly affect HbA1c accuracy, with TINIA showing better correlation with glycemic control than HPLC in affected individuals.
• MCV values ≤ 80 fL can be a useful preliminary indicator for selecting samples requiring TINIA analysis.
• HPLC can serve as a cost-effective tool for screening hemoglobinopathies in diabetic populations in Bangladesh, aiding in the management of related complications.