Different forms of Hb Le Lamentin. An unexpected finding in Hba1c quantification

• Find Hb Le Lamentin during a diabetes control using ion-exchange HPLC (Variant™ II Turbo)
• Describing a first case of homozygous Hb Le Lamentin and the first double heterozygous Hb Le Lamentin/Hb City of Hope
• This hemoglobin variant was studied using capillary zone electrophoresis (Sebia) and ion-exchange HPLC (Variant™ II Turbo).

ObjectivesGlycated hemoglobin (HbA1c) is accepted as the most trusted marker for monitoring patients with diabetes mellitus. Ion-exchange high-performance liquid chromatography (HPLC) is one of the most widely used methods for HbA1c analysis. The presence of a hemoglobin variant can interfere with HbA1c quantification, requiring other analyses to clarify the results.Herein, we present two cases of Hb Le Lamentin, which, although they were the same variant, were thought to correspond to different hemoglobinopathies because of their percentages.Design and methodsTwo male patients presented with an anomalous peak between HbA1c and HbA0 during a routine analysis of HbA1c using ion-exchange HPLC (Variant™ II Turbo).The hemoglobin variants were studied using capillary zone electrophoresis with the Sebia system, and the globin chains were analyzed by reverse-phase HPLC. A genetic analysis was performed using automated sequencing of the α2 and β genes.ResultsIn this work, we describe the first case of homozygous Hb Le Lamentin and the first double-heterozygous case of Hb Le Lamentin/Hb City of Hope.ConclusionsAlthough the presence of these variants does not lead to clinical anomalies, it also does not affect hematologic parameters. The variants have an impact on the determination of glycated hemoglobin levels using ion-exchange HPLC because the retention time interferes with the elution time of HbA1c, resulting in a falsely reduced value. Therefore, it is necessary to either recalculate the result or use another measurement method.