Journal of Medical Surgical and Allied Sciences, Volume 2, Issue 1 : 1-6. Doi : 10.37446/jmedsurg/cr/2.1.2024.1-6

Case Report

OPEN ACCESS | Published on : 30-Jun-2024

Discordantly low hemoglobin A1c in the context of marked hyperglycemia

• Mustafa Ibrahim Abbas
• Department of Hematology and Immunohematology, Faculty of Medical Laboratory Sciences, University of Gezira, Wad Medani, Sudan.
• Mubarak Ahmed Elshafia
• Department of Hematology and Immunohematology, Faculty of Medical Laboratory Sciences, University of Gezira, Wad Medani, Sudan.
• Khalid Abdelsamea Mohamedahmed
• Department of Hematology and Immunohematology, Faculty of Medical Laboratory Sciences, University of Gezira, Wad Medani, Sudan.; Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jerash University, Jerash, Jordan. khalid.gu89@gmail.com. ORCID No: 0000-0001-7084-6106.
• Yousif Abdelhameed Mohammed
• Department of Clinical Chemistry, Faculty of Medical Laboratory Sciences, University of Gezira, Wad Medani, Sudan.
• Sarah Hameed Aldhafiri
• Clinical Laboratory Department, Collage of Applied Medical Science, University of Hafr Albatin, Hafr Albatin, Saudi Arabia.
• Fayhaa Mahmood Madani Hamood
• Department of Medicine, Wad Medani Teaching Hospital, Wad Medani, Sudan.
• Mazza Alsayed Adam
• Department of Medical Laboratories, Almumayaz Advance Medical Laboratories, Wad Medani, Sudan.
• Omar Osman Mohamed
• Department of Medical Laboratories, Almumayaz Advance Medical Laboratories, Wad Medani, Sudan.
• Ahmed Mohamed Ahmed
• Department of Medical Laboratories, Almumayaz Advance Medical Laboratories, Wad Medani, Sudan.

Abstract

Background: Hemoglobin A1c (HbA1c) acts as the primary biomarker for evaluating long-term glucose regulation. Nevertheless, high concentrations of fetal hemoglobin (HbF) can affect the accuracy of HbA1c assays in a manner dependent on the method used, possibly leading to falsely low HbA1c readings even when there is considerable hyperglycemia.

Case Presentation: The outpatients showed significant hyperglycemia (random blood glucose: 433 mg/dL) and highly positive urine ketones (+++), aligning with a diagnosis of diabetic ketoacidosis. Ironically, HbA1c obtained through standard immunoassay was 6.5%, which is categorized within the non-diabetic range. Follow-up hemoglobin fractionation showed an increased fetal hemoglobin (HbF) concentration of 4.1%, causing worry about assay interference and leading to a reassessment of the HbA1c outcome.

Conclusion: Elevated fetal hemoglobin (>4%) can falsely lower HbA1c, especially with immunoassay or boronate-affinity methods. Ion-exchange HPLC or electrophoresis is recommended, and clinicians should integrate alternative glycemic markers or continuous glucose monitoring to guide management accurately.

Keywords

hemoglobin A1c, fetal hemoglobin, HbF interference, Ion-exchange HPLC, capillary electrophoresis, glycemic markers

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