Laboratory Haematology
Contributions
Type: Publication Only
Background
The presence of a haemoglobin variant (Hb variant) influences the glycated haemoglobin (HbA1c) analysis in a method-depending manner and may erroneously lead to underestimated HbA1c measurements by high performance liquid chromatography (HPLC).
Aims
The aim of this study is the retrospective registration of the cases of Hb variant detected during HbA1c analysis by HPLC, in order to reevaluate the use of this specific method.
Methods
All patients who had their HbA1c levels determined in our laboratory during the period of time from 01-01-2004 to 31-03-2013 were included in the study. The measurements of HbA1c were performed by automated reversed phase cation exchange HPLC on an ADAMS™ A1c HA-8160, ARKRAY® analyzer. All Hb variant cases found during routine HbA1c analysis and further identified with HPLC analyzer (HLC-723 G7 β-Thalassemia Mode, TOSOH®) were recorded. Only one HbA1c result per patient was included in the study.
Results
Out of a total of 12617 patients, 122 (54 men & 68 women) was found to have Hb variant. In particular, 83 patients (68,03%) had Hb-O Arab (1 homogyzous & 82 heterozygous), 36 patients (29,5%) had HbS (heterozygous), two patients (1,64) had HbJ (heterozygous) and one patient (0,82%) had HbD (heterozygous). The determination of HbA1c was impossible in the case of homozygous O-Arab (no s-A1c peak detected). In all cases, the presence of Hb variant was first diagnosed during the routine HbA1c analysis.
Summary
The analysis of HbA1c using the HPLC method is a simple and reliable screening test for Hb variant. The incidental finding of haemoglobinopathy is very important, because old people that usually suffer from diabetes mellitus, probably did not have previous haemoglobinopathy investigation. Furthermore, homozygous O-Arab and heterozygous HbS present a significant clinical importance. As the measurement of HbA1c can potentially be affected by the presence of a Hb variant, and in order to avoid mismanagement of diabetes mellitus (pre-diabetes, diagnosis, monitoring) in individuals with Hb variants, the visual inspection of chromatograms obtained from HPLC analysis for the detection of additional peaks is recommended. The laboratory should report the presence of Hb variant with the HbA1c result.
Keyword(s): Glycosylation, Hemoglobin variants, Hemoglobinopathy
Session topic: Publication Only
Type: Publication Only
Background
The presence of a haemoglobin variant (Hb variant) influences the glycated haemoglobin (HbA1c) analysis in a method-depending manner and may erroneously lead to underestimated HbA1c measurements by high performance liquid chromatography (HPLC).
Aims
The aim of this study is the retrospective registration of the cases of Hb variant detected during HbA1c analysis by HPLC, in order to reevaluate the use of this specific method.
Methods
All patients who had their HbA1c levels determined in our laboratory during the period of time from 01-01-2004 to 31-03-2013 were included in the study. The measurements of HbA1c were performed by automated reversed phase cation exchange HPLC on an ADAMS™ A1c HA-8160, ARKRAY® analyzer. All Hb variant cases found during routine HbA1c analysis and further identified with HPLC analyzer (HLC-723 G7 β-Thalassemia Mode, TOSOH®) were recorded. Only one HbA1c result per patient was included in the study.
Results
Out of a total of 12617 patients, 122 (54 men & 68 women) was found to have Hb variant. In particular, 83 patients (68,03%) had Hb-O Arab (1 homogyzous & 82 heterozygous), 36 patients (29,5%) had HbS (heterozygous), two patients (1,64) had HbJ (heterozygous) and one patient (0,82%) had HbD (heterozygous). The determination of HbA1c was impossible in the case of homozygous O-Arab (no s-A1c peak detected). In all cases, the presence of Hb variant was first diagnosed during the routine HbA1c analysis.
Summary
The analysis of HbA1c using the HPLC method is a simple and reliable screening test for Hb variant. The incidental finding of haemoglobinopathy is very important, because old people that usually suffer from diabetes mellitus, probably did not have previous haemoglobinopathy investigation. Furthermore, homozygous O-Arab and heterozygous HbS present a significant clinical importance. As the measurement of HbA1c can potentially be affected by the presence of a Hb variant, and in order to avoid mismanagement of diabetes mellitus (pre-diabetes, diagnosis, monitoring) in individuals with Hb variants, the visual inspection of chromatograms obtained from HPLC analysis for the detection of additional peaks is recommended. The laboratory should report the presence of Hb variant with the HbA1c result.
Keyword(s): Glycosylation, Hemoglobin variants, Hemoglobinopathy
Session topic: Publication Only