Screening for hemoglobinopathies during routine hemoglobin A1c testing using the Tosoh G7 Glycohemoglobin Analyzer

Area of Science:

• Clinical Chemistry
• Hematology
• Diagnostic Screening

Background:

• Diabetes mellitus affects approximately 5.1% of the US population, necessitating regular monitoring of glycemic control.
• Hemoglobin (Hb) A1c levels are routinely measured using ion exchange chromatography.
• Hemoglobin variants and hemoglobinopathies can cause abnormal peaks on chromatograms during HbA1c testing.

Purpose of the Study:

• To evaluate the utility of detecting abnormal peaks during routine Hb A1c measurements as a screening tool for hemoglobin variants and hemoglobinopathies.
• To characterize and report retention times (RTs) for various hemoglobin abnormalities on the G7 Glycohemoglobin Analyzer.

Main Methods:

• Analysis of 366 specimens with abnormal peaks from routine Hb A1c testing using the G7 Glycohemoglobin Analyzer.
• Characterization of Hb variants and hemoglobinopathies through alkaline and acid electrophoresis, Hb S solubility testing, and clinical data.
• Determination of mean retention times (RTs) for identified hemoglobin abnormalities.

Main Results:

• Sickle cell trait identified in 252 cases (mean RT 1.44 min).
• Hb C trait identified in 82 cases (mean RT 1.66 min).
• Retention times for other abnormalities including sickle cell disease, homozygous Hb C disease, and various alpha-chain variants were determined.

Conclusions:

• Routine Hb A1c testing serves as a potential screening tool for common hemoglobin variants and hemoglobinopathies.
• The study provides previously unreported RTs for the G7 Glycohemoglobin Analyzer, aiding in diagnosis.
• This approach can facilitate further testing for undiagnosed patients and confirm causes in those with known abnormalities.