Aberrant glycated haemoglobin (HbA1c) results leading to haemoglobinopathy diagnosis in four Belgian patients

Abstract

Introduction:

We report four cases in which haemoglobinopathy screening was triggered following aberrant HbA1c analysis. Either the HbA1c assay was unable to produce a quantifiable result or it showed the presence of an extra fraction and/or the result was discordant with the clinical context.

Case report:

In the reported four patients, all from Caucasian, Belgian descent, Hb analysis was performed using cation-exchange high performance liquid chromatography. If necessary, additional Hb electrophoresis was carried out to establish a preliminary (biochemical) diagnosis. Definitive diagnosis was obtained for every sample through DNA-analysis. Three patients were carriers of Hb J-Toronto and one of Hb Stanleyville-II.

Discussion:

This report underlines the importance of correct interpretation of HbA1c results to avoid mismanagement of (diabetic) patients. Since neither the RBC indices, the clinical context, nor the ethnicity of these patients was suspicious for an underlying haemoglobinopathy, the aberrant HbA1c result was the only indicator for further investigation. Laboratory personnel and clinicians should be aware of the possibility of uncommon, sometimes clinically unsuspected, Hb variants to cause aberrant HbA1c values, even in populations with low prevalence for haemoglobinopathies. Further analysis should be prompted to obtain definitive diagnosis. Alternative methods for monitoring glycaemic control should be used.

Keywords:

• Haemoglobinopathy
• Hb variant
• HbA1c
• Hb Stanleyville-II
• Hb J-Toronto

Acknowledgements

The authors acknowledge and thank the clinical biologists of the Heilig Hart Regional Hospital Leuven and A.Z. St.-Dimpna Hospital Geel for their cooperation.