Haemoglobin Graz, a novel haemoglobin variant

Pathology consultation on HbA(1c) methods and interferences

OBJECTIVES

To review the various hemoglobin (Hb) A1c methods, with a focus on interferences resulting from Hb variants.

METHODS

HbA1c is a marker used for the diagnosis and management of diabetes. Each available HbA1c method has advantages and challenges, such as its susceptibility to interferences.

RESULTS

The presence of Hb variants and/or abnormalities in RBC turnover cannot only interfere analytically with HbA1c measurements but also may affect the clinical interpretation of HbA1c values.

CONCLUSIONS

Familiarity with the advantages and challenges of the various methods used for HbA1c testing is essential when establishing therapeutic management and goals based on HbA1c results, especially in populations with a high prevalence of Hb variants.

Hemoglobin variants recently detected in Austria

Measurement of glycated hemoglobin (HbAtc) is used for routine management of diabetic patients. Glucose linkage to HbAtc reflects mean blood glucose levels during the last 3 months before examination. Various methods for HbA1c determination show abnormal values with hemoglobin variants. In some diabetic patients excessively high HbA1c values with high-performance liquid chromatography (HPLC) led to the detection of Hb Graz. In addition to Hb Graz, other silent hemoglobin variants have been found in Austria. Here we review Hb Graz, Hb Sherwood Forest, and Hb Okayama detected while using HPLC for the measurement of HbA1c in diabetic patients.