Effect of HbE and HbH on HbA1C level by ionic exchange HPLC comparing to immunoturbidimetry

Case report: Effect of Hb E heterozygosity on HbA1c value by the Tosoh HLC-723G11

Objective

We report the effect of Hb E heterozygosity on HbA1c value by the Tosoh HLC-723G11.

Case report

A 45 years-old Chinese woman presented with an abnormally low HbA1c level of 3.7% (3.9%-6.1%) in a health examination. Fasting blood glucose was normal. Blood routine examination and serum bilirubin were in the normal range. HbA1c was determined by Tosoh HLC-723G11. There was an abnormal peak between A1c and A0 on the chromatogram. Hemoglobin electrophoresis indicated that the Hb E zone accounted for 25.1%. The β-thalassemia-related genes (mutant type) were βE M/N, and the related gene CD26 (A > G) was mutated. OGTT indicated prediabetes.

Conclusion

Hb E heterozygosity may reduce HbA1c value with abnormal chromatograms, as determined by a Tosoh HLC G11 analyzer. The Tosoh HLC G11 analyzer can well identify Hb E variation. In this case, further blood glucose-related tests should be performed to avoid missed diagnoses. However, a large sample size is needed to confirm this conclusion.

Associations between HbA1c-derived estimated average glucose and fasting plasma glucose in patients with normal and abnormal hemoglobin patterns

Fasting plasma glucose (FPG) and HbA1c are well-known tests for monitoring short and long-term glycemic control, respectively. Estimated average glucose (eAG) is derived from the HbA1c for expression in the same units as FPG. The present study aimed to evaluate the association between eAG and FPG values. This retrospective study was performed on 1285 patients who measured the FPG and HbA1c (capillary electrophoresis method) values on the same day. They were initially divided into 3 hemoglobin-pattern groups, normal, HbE, and high HbA₂, and then these 3 groups were further subdivided into whole group, subgroup 1 (HbA1c ≤ 7%) and subgroup 2 (HbA1c >7%) for analytical comparisons. The eAG values were calculated using Nathan's equation. The differences, agreements, and correlations between eAG and FPG were evaluated. Good agreements and strong positive correlations between eAG and FPG values were observed in all 3 whole groups. In subgroup analysis, the degrees of agreement and correlation depended on the level of glycemic control, as all associations became stronger with better glycemic control. Additionally, the HbA1c levels and different eAG-FPG values between the normal and other groups were not significantly different in either whole group or subgroup comparisons. Our study found good agreements and strong positive correlations between eAG and FPG in all groups, indicating that high HbA₂ or HbE did not affect the HbA1c levels or thus the associations between eAG and FPG. Reporting the eAG together with the HbA1c value should help improve the understanding of glycemic status in patients, leading to improved blood glucose control.

HbA1C as a marker of retrograde glycaemic control in diabetes patient with co-existed beta-thalassaemia: A case report and a literature review

WHAT IS KNOWN AND OBJECTIVE

The HbA1C marker used in assessing diabetes control quality is not sufficient in diabetes patients with thalassaemia.

CASE DESCRIPTION

A male diabetic patient with thalassaemia was hospitalized due to distal neuropathic pain, right toe trophic ulcer, unacceptable five-point glycaemic profile and recommended HbA1C value. After simultaneously initiated insulin therapy and management of ulcer by hyperbaric oxygen, the patient showed improved glycaemic control and ulcer healing, which led to the patient's discharge.

WHAT IS NEW AND CONCLUSION

In thalassaemia and haemoglobinopathies, due to discrepancies in the five-point glycaemic profile and HbA1C values, it is necessary to measure HbA1C with a different method or to determine HbA1C and fructosamine simultaneously.

Measurement of HbA1c and HbA2 by Capillarys 2 Flex Piercing HbA1c programme for simultaneous management of diabetes and screening for thalassemia

Introduction

Thalassemia could interfere with some assays for haemoglobin A_1c (HbA_1c) measurement, therefore, it is useful to be able to screen for thalassemia while measuring HbA_1c. We used Capillarys 2 Flex Piercing (Capillarys 2FP) HbA_1c programme to simultaneously measure HbA_1c and screen for thalassemia.

Materials and methods

Samples from 498 normal controls and 175 thalassemia patients were analysed by Capillarys 2FP HbA_1c programme (Sebia, France). For method comparison, HbA_1c was quantified by Premier Hb9210 (Trinity Biotech, Ireland) in 98 thalassaemia patients samples. For verification, HbA_1c from eight thalassaemia patients was confirmed by IFCC reference method.

Results

Among 98 thalassaemia samples, Capillarys 2FP did not provide an HbA_1c result in three samples with HbH due to the overlapping of HbBart’s with HbA_1c fraction; for the remaining 95 thalassaemia samples, Bland-Altman plot showed 0.00 ± 0.35% absolute bias between two systems, and a significant positive bias above 7% was observed only in two HbH samples. The HbA_1c values obtained by Capillarys 2FP were consistent with the IFCC targets (relative bias below ± 6%) in all of the eight samples tested by both methods. For screening samples with alpha (α-) thalassaemia silent/trait or beta (β-) thalassemia trait, the optimal HbA₂ cut-off values were ≤ 2.2% and > 2.8%, respectively.

Conclusions

Our results demonstrated the Capillarys 2FP HbA_1c system could report an accurate HbA_1c value in thalassemia silent/trait, and HbA₂ value (≤ 2.2% for α-thalassaemia silent/trait and > 2.8% for β-thalassemia trait) and abnormal bands (HbH and/or HbBart’s for HbH disease, HbF for β-thalassemia) may provide valuable information for screening.

Characterization of a Double Heterozygote HbE/β(+) Thalassemia IVS 1-1 [G>T] in a Juvenile Diabetic

The present case report describes the molecular and proteomic based study of Hb variant HbE associated with β(+) thalassemia IVS 1-1 G>T, in a juvenile diabetic patient. Given the ethnic origin and mobility of the variant hemoglobin at alkaline pH, HbE would be suspected. But hematologically and clinically abnormality being detected, HPLC and Electrophoresis not being able to characterize due to retention time and band being in region of HbA2, respectively, further characterization of hemoglobinopathy was made using MALDI and IVS 1-1 G>T being validated by reverse dot blot hybridization. Capillary electrophoresis was also employed in order to separate HbE and HbA2 bands. This case report being first of its kind, wherein a HbE/β(+) thalassemia has been characterized using multiple techniques.

Hb H Interference on Measurement Of HbA1c With Ion-Exchange HPLC

In this article, an interference caused by hemoglobin H (Hb H), during the measurement of hemoglobin A1c (HbA1c) with ion exchange high pressure liquid chromatography (HPLC) method, was presented in blood sample of a 20-year-old male patient. HbA1c measurement was performed with Agilent 1200 HPLC system using a commercial Recipe HbA1c ion-exchange column. Hemoglobin electrophoresis was performed with Interlab G26 agarose electrophoresis automated compact system. HbA1c level was 18.2% and HbA0 level was 81.5% with ion-exchange HPLC method. Patient’s fasting serum glucose was assessed before HbA1c measurement and the result was 165 mg/dL (9.16 mmol/L). On the other hand, the result of HbA0 was 87.9%, Hb H was 10.8% and Hb A2 was 1.3% with electrophoresis. Whole blood test values were within reference ranges except MCV. MCV value was 79.6 fL. It is important to keep in mind that HbA1c level might be considered falsely high with ion-exchange HPLC method because of Hb H containing sample.

Hemoglobin variants detected by hemoglobin A1c (HbA1c) analysis and the effects on HbA1c measurements

Background:

Hemoglobin (Hb) A1c is a tool widely used to monitor long-term glycemic control in diabetic patients. The objective of our study is to compare the HbA1c values measured on high performance liquid chromatography (HPLC) and immunoassay in patients who were detected to have hemoglobin variant after HbA1c analysis.

Materials and Methods:

We compared the HbA1c values measured using the Arkray Adams A1c HA-8160 (HPLC method) and Roche Cobas Integra (immunoturbidimetric method) from diabetic patients who were diagnosed with hemoglobin variants.

Results:

Forty-three diabetic patients were diagnosed with hemoglobin variants: 13 elevated Hb F, 12 Hb E trait, seven Hb S trait, seven Hb D trait, two Hb E / beta-Thalassemia, one Hb C trait, and one homozygous Hb S.

Conclusion:

Knowledge of hemoglobin variants affecting HbA1c measurements is essential, in order to avoid mismanagement of diabetic patients.

Influence of hemoglobin E on measurement of hemoglobin A1c by immunoassays

BACKGROUND

Many assays used for HbA1c measurement can be interfered by hemoglobin variants. Hemoglobin E is one of the most common variant. Effect of HbE on high performance liquid chromatography was widely reported but not on immunoassay.

OBJECTIVE

To determine the effect of hemoglobin E on HbA1c values by immunoassay methods.

MATERIAL AND METHODS

Two immunoassays were used for measurement of HbA1c in samples with hemoglobin type as A2A (normal controls, n=60), EA (heterozygous hemoglobin E, n=151), and EE (homozygous hemoglobin E, n=43). Results within each assay and each hemoglobin typing group were compared. Mann-Whitney U test, Pearson's correlation and linear regression analysis were used.

RESULTS

There were significant differences of HbA1c values between normal controls and hemoglobin E-contained samples. Correlation between two assays was worse in the presence of hemoglobin E comparing to normal controls.

CONCLUSION

Hemoglobin E can affect the immunoassays used for HbA1c measurement. Further studies are needed to understand the mechanism of interference.

Hemoglobin variant HbE found in two South Asian diabetic patients

Glycohemoglobin, also known as hemoglobin (Hb) A(1c), is a marker of long-term glycemic control in patients with diabetes. We present two South-Asian diabetic patients whose HbA(1c) peaks were not measurable using high performance liquid chromatography (HPLC). Further investigations showed that these patients were homozygous for a hemoglobin variant, HbE (beta26 Glu-->Lys). Because of the increasing numbers of immigrants in Japan, area-specific hemoglobinopathies are now encountered more frequently than before. Thus, if discrepant results are found on an HbA(1c) assay or if the HbA(1c) value cannot be measured, such patients should be screened for hemoglobinopathies and alternative measurements for monitoring diabetes should be considered.

Problem of using hemoglobin A1C measurement in endemic area of hemoglobinopathy

Diabetes mellitus (DM) is a frequent disorder affecting individuals of all ages. Glycohemoglobin (GHb) has a key role in the assessment of glycemic control in diabetic patients. Generally, GHb is measured as hemoglobin (Hb) A1C and is the result of an irreversible non-enzymatic glycation of the beta chain of hemoglobin A. HbA1C is used routinely to assess long term glycemic control in patients with DM. A variety of patient- and laboratory-related factors can adversely affect the measurement of HbA1C in patients harboring Hb variants or derivatives. In this article, problem of using hemoglobin A1C measurement in endemic area of hemoglobinopathy is addressed.

Effects of beta thalassemia minor on results of six glycated hemoglobin methods

BACKGROUND

Beta-thalassemia minor (BTM) is a common benign condition that can be present in patients with diabetes mellitus. There are conflicting reports about the effect of BTM on glycated hemoglobin (gHb) measurements. We evaluated 6 gHb methods using samples from non-diabetic subjects with BTM.

METHODS

Samples submitted for hemoglobin phenotype analysis were evaluated. A total of 57 samples (30 controls and 27 with BTM) from non-diabetic subjects were selected. GHb analysis was performed by Tosoh A1c 2.2+, Primus CLC 330, Bayer DCA 2000, Beckman Coulter, Synchron CX7 and LX20, and Roche Tina-quant II assays.

RESULTS

The A1c 2.2+, CLC 330, DCA 2000 and Tina-quant II assays showed no statistically significant difference between the control and BTM groups. In contrast, BTM results were significantly higher than controls on the Synchron CX7 analyzer and borderline significant on the Synchron LX20 (p=0.051). Further investigation demonstrated an increase in Synchron %HbA(1c) results with decreasing hemoglobin concentrations.

CONCLUSIONS

In this study using samples from subjects with normal or near-normal gHb, BTM does not affect gHb measurements per se. However, the Synchron methods yielded higher results for samples with lower hemoglobin concentrations, like those that can be seen in BTM. The Synchron method was improved at the end of 2003, which minimized this problem.