Interference of the Hope Hemoglobin With Hemoglobin A1c Results

Area of Science:

• Clinical Chemistry
• Hematology
• Analytical Biochemistry

Background:

• Hemoglobin A1c (HbA1c) is the standard for diabetes mellitus diagnosis and management.
• Variant hemoglobins can interfere with HbA1c assays, leading to inaccurate results.
• Hb Hope is a rare variant that can cause analytical challenges.

Observation:

• A 52-year-old Indian man with impaired glucose tolerance presented with spuriously high HbA1c levels (47.8% by HPLC, 44.0% by immunoassay).
• No variant Hb peak was detected by HPLC.
• Capillary electrophoresis revealed a large variant Hb peak (42.0%) and an HbA1c of 6.8%, suggesting heterozygous Hb Hope.

Findings:

• Heterozygous Hb Hope can lead to falsely elevated HbA1c results on HPLC and turbidimetric immunoassays.
• Capillary electrophoresis identified the variant but accurate HbA1c quantification was hindered by overlapping peaks.
• Hb Hope is typically asymptomatic but poses significant analytical challenges.

Implications:

• Laboratory professionals must be aware of Hb Hope to prevent misdiagnosis and ensure patient safety.
• This case underscores the limitations of current HbA1c assay methods in the presence of certain hemoglobin variants.
• Accurate diabetes management relies on recognizing and addressing analytical interferences in HbA1c testing.