ABSTRACT
BACKGROUND AND AIMS: The concentration of glycated hemoglobin (HbA1c) is an essential diagnostic and therapeutic biomarker in diabetes mellitus. However, it is known that Hb structural variants and synthesis disorders, can affect the HbA1c measurement in different assays. Although the analytical interference of various hemoglobinopathies on the chromatographic measurement of HbA1c using HPLC has been well studied, data on the interference on the enzymatic assay are few. MATERIALS AND METHODS: In this multi-center study, a large number (n = 104) of 33 different hemoglobin variants were collected over a period of one year and compared between an HPLC (Tosoh G8 and G11) and an enzymatic assay (Abbott Alinity c). RESULTS: A good comparability between ion-exchange HPLC and the Alinity assay for most Hb variants was found. However, we were able to determine for the first time that certain Hb variants (Hb Okayama, HbAE, Hb Lepore) can lead to clinically relevant discordant results. HbF (>5%) can already cause a relevant aberration. CONCLUSIONS: Overall, using the Abbott HbA1c assay in the presence of certain hemoglobin variants can induce clinically relevant interference that can affect diagnosis and therapy monitoring decisions, mainly because the enzymatic assay cannot provide any information about Hb variants.