[Hemoglobin C Variant Affecting Glycated Hemoglobin Test Results: A Rare Case Report]

Area of Science:

• Clinical Chemistry
• Hematology
• Genetics

Background:

• Glycosylated hemoglobin (A1C) is a key diagnostic marker for diabetes management.
• Hemoglobin (Hb) variants can interfere with A1C testing methods, leading to inaccurate results.
• The prevalence and impact of specific Hb variants, like Hb C, on A1C assays in diverse populations require investigation.

Observation:

• High-performance liquid chromatography (HPLC) indicated decreased A1C levels in the presence of an unknown hemoglobin variant.
• Capillary electrophoresis confirmed the discrepancy and revealed abnormal peaks, suggesting the presence of Hb variants.
• Hemoglobin sequencing identified the variant as Hemoglobin C (Hb C) in the Chinese population.

Findings:

• Hemoglobin C (Hb C) significantly affects A1C test results, causing underestimation when using HPLC.
• Electrophoresis can help identify the presence of Hb variants but may still show abnormal patterns.
• Accurate identification of Hb variants is crucial for correct interpretation of A1C values.

Implications:

• Uncommon hemoglobin variants can be overlooked, potentially leading to misdiagnosis or inappropriate treatment decisions.
• A standardized explanatory reporting model for A1C tests, detailing methodology and graph analysis, is recommended.
• Implementing comprehensive reporting can mitigate the clinical impact of Hb variants on A1C testing accuracy.