Erroneous HbA1c measurements in the presence of β-thalassemia and common Chinese hemoglobin variants

HbA1c or fructosamine on evaluating glucose intolerance in children with beta- thalassemia

BACKGROUND

Beta-thalassemia major (β-TM) patients are more likely to experience blood glucose intolerance and to date; the blood markers that could evaluate this are debatable. So, this study aimed to assess the roles of glycated hemoglobin A1c (HbA1c) and fructosamine in evaluating glucose intolerance in children with β-TM and figuring out role of insulin resistance in these patients.

METHODS

One hundred children diagnosed with β-TM and 100 age and sex-matched controls were enrolled. Fasting plasma glucose (FPG), 2-h post-prandial blood glucose (2-h PG), HbA1c, fructosamine, fasting insulin level (FINS), insulin resistance index (HOMA-IR), and insulin sensitivity index (HOMA-IS) were evaluated.

RESULTS

FPG and 2-h PG revealed glucose intolerance in 51 patients (51%), 19 of them had diabetes mellitus. HbA1c, fructosamine, FINS, and HOMA-IR showed a high statistically significant increase in patients compared to controls, (P < 0.001). Results revealed fructosamine was more specific in detecting prediabetes state and more sensitive in identifying diabetes mellitus in our patients when compared to HbA1c.

CONCLUSIONS

Despite controversies on HbA1c in children with β-TM, it is still valuable in glucose intolerance detection. Fructosamine showed more sensitivity and specificity. Furthermore, insulin resistance was prevalent in children with β-TM highlighting the necessity of regular glycemic state evaluation.

IMPACT

Glucose intolerance is a common complication in beta thalassemia patients. Conflicting data was reported about the role of HbA1c and fructosamine in evaluating glucose intolerance in thalassemic patients. Fructosamine does not yet have a threshold that may be used to distinguish between patients who have diabetes mellitus and those who do not. Fructosamine was more specific in detecting blood glucose intolerance compared to HbA1c and was more sensitive for diagnosing diabetes mellitus. Insulin resistance was common in patients with beta-thalassemia and often present before the onset of overt diabetes.

Evaluation of effects from hemoglobin variants on HbA1c measurements by different methods

OBJECTIVES

The impact of seven hemoglobin variants (Hb Q-Thailand, Hb G-Honolulu, Hb Ube-2, Hb New York, Hb J-Bangkok, Hb G-Coushatta, and Hb E) on the outcome of HbA1c was investigated for six methods by comparing with liquid chromatography-tandem mass spectrometry (LC/MS/MS) reference method.

METHODS

Twenty-nine normal and 112 variant samples were measured by LC/MS/MS, Sebia Capillarys 3 TERA, Intelligene Biosystems QuanTOF, Premier Hb9210, Arkray HA-8190V, Bio-Rad D-100, and Tosoh G11, then evaluated for correlation, consistency, and mean relative bias among six methods. The lowest biological variation bias of ±2.8 % was an acceptable standard.

RESULTS

All methods showed poor correlation and consistency with LC/MS/MS for Hb E. The unacceptable biases were observed for Capillarys 3 TERA (-14.4 to -3.7 % for Hb Q-Thailand, Hb Ube-2, Hb New York, Hb J-Bangkok and Hb E), QuanTOF (-8.3 to -2.9 % for Hb Ube-2, Hb New York and Hb G-Coushatta), Premier Hb9210 (-18.3 to -3.6 % for Hb Q-Thailand, Hb Ube-2, Hb New York, Hb J-Bangkok and Hb E), HA-8190V variant mode (-17.3 to 6.6 % for Hb G-Honolulu, Hb Ube-2, Hb New York, Hb G-Coushatta and Hb E). All variant samples showed larger biases than ±2.8 % comparing HA-8190V fast mode, D-100, and G11 with LC/MS/MS.

CONCLUSIONS

The accuracy of different HbA1c methods was influenced by some Hb variants, especially Hb Ube-2 and Hb New York. Thus, laboratories need to choose appropriate methods to measure HbA1c with different Hb variants.

Diagnosis and screening of abnormal hemoglobins

Hemoglobin (Hb) abnormalities, such as thalassemia and structural Hb variants, are among the most prevalent inherited diseases and are associated with significant mortality and morbidity worldwide. However, there were not comprehensive reviews focusing on different clinical analytical techniques, research methods and artificial intelligence (AI) used in clinical screening and research on hemoglobinopathies. Hence the review offers a comprehensive summary of recent advancements and breakthroughs in the detection of aberrant Hbs, research methods and AI uses as well as the present restrictions anddifficulties in hemoglobinopathies. Recent advances in cation exchange high performance liquid chromatography (HPLC), capillary zone electrophoresis (CZE), isoelectric focusing (IEF), flow cytometry, mass spectrometry (MS) and polymerase chain reaction (PCR) etc have allowed for the definitive detection by using advanced AIand portable point of care tests (POCT) integrating with smartphone microscopic classification, machine learning (ML) model, complete blood counts (CBC), imaging-based method, speedy immunoassay, and electrochemical-, microfluidic- and sensing-related platforms. In addition, to confirm and validate unidentified and novel Hbs, highly specialized genetic based techniques like PCR, reverse transcribed (RT)-PCR, DNA microarray, sequencing of genomic DNA, and sequencing of RT-PCR amplified globin cDNA of the gene of interest have been used. Hence, adequate utilization and improvement of available diagnostic and screening technologies are important for the control and management of hemoglobinopathies.

Recent advances in laboratory hematology reflected by a decade of CCLM publications

On the occasion of the 60th anniversary of Clinical Chemistry and Laboratory Medicine (CCLM) we present a review of recent developments in the discipline of laboratory hematology as these are reflected by papers published in CCLM in the period 2012–2022. Since data on CCLM publications from 1963 to 2012 are also available, we were able to make a comparison between the two periods. This interestingly revealed that the share of laboratory hematology papers has steadily increased and reached now 16% of all papers published in CCLM. It also became evident that blood coagulation and fibrinolysis, erythrocytes, platelets and instrument and method evaluation constituted the ‘hottest’ topics with regard to number of publications. Some traditional, characteristic CCLM categories like reference intervals, standardization and harmonization, were more stable and probably will remain so in the future. With the advent of important newer topics, like new coagulation assays and drugs and cell population data generated by hematology analyzers, laboratory hematology is anticipated to remain a significant discipline in CCLM publications.

HbA1c and biomarkers of diabetes mellitus in Clinical Chemistry and Laboratory Medicine: ten years after

Since its discovery in the late 1960s, HbA_1c has proven to be a major biomarker of diabetes mellitus survey and diagnosis. Other biomarkers have also been described using classical laboratory methods or more innovative, non-invasive ones. All biomarkers of diabetes, including the historical glucose assay, have well-controlled strengths and limitations, determining their indications in clinical use. They all request high quality preanalytical and analytical methodologies, necessitating a strict evaluation of their performances by external quality control assessment trials. Specific requirements are needed for point-of-care testing technologies. This general overview, which describes how old and new tools of diabetes mellitus biological survey have evolved over the last decade, has been built through the prism of papers published in Clinical Chemistry and Laboratory Medicine during this period.

Indicators of glucose dysregulation and the relationship with iron overload in Chinese children with beta thalassemia major

INTRODUCTION

Patients with beta thalassemia major (TM) have a higher risk of diabetes and an abnormal oral glucose tolerance test (OGTT), but there is no single agree monitoring parameter that reflects glycemic status. The possible mechanisms include iron overload and blood transfusion, but they require further investigation.

PURPOSE

This study explored the role of glycated hemoglobin A1c (HbA1c), fructosamine, and glycated albumin (GA) in evaluating the glucose dysregulation and to determine the potential relationship between iron deposition and glucose metabolism disorder in beta TM.

METHODS

A cross-sectional study was performed on 118 patients with beta TM and the control group consisted of 33 healthy children with no statistical differences in age, sex, and body mass index (BMI). Fast plasma glucose (FPG), fast insulin (FINS), insulin resistance index (HOMA-IRI), and insulin sensitivity index (HOMA-ISI) were compared between the patient and control groups. HbA1c, GA, fructosamine, and serum ferritin (SF) were measured in the patient group. OGTT, as well as heart and liver magnetic resonance imaging (MRI) T2*, was performed. For all statistical analyses, SPSS 21.0 was used and p < 0.05 was accepted as statistically significant.

RESULTS

FPG, FINS, and HOMA-IRI were significantly increased while HOMA-ISI decreased in the beta TM patients when compared with those in the control group. In patients with beta TM, 17 (14.41%) of patients had been diagnosed with diabetes, while 48 (40.68%) had both impaired fasting glucose and impaired glucose tolerance. HbA1c, GA, and fructosamine were increased according to the degree of abnormal glucose metabolism. Statistically significant differences were found in age, SF, and cardiac T2* between the abnormal and normal OGTT groups.

CONCLUSION

HbA1c may be used as a significant measure for monitoring glycemic levels in patients with beta TM. Furthermore, GA and fructosamine were alternative indicators of glucose status. Patients with heart iron deposition or an SF > 4000 μg/L were prone to abnormal glucose metabolism, so chelation therapy should be reinforced.

Significantly High HbA1c in Diabetic Patient with Hb J: Case Report

Glycated hemoglobin (HbA_1c) is used to monitor the long-term management of diabetes and reflects the average blood glucose level over the past three months. Hb J is an alpha-globin gene variant that occurs less commonly but can interfere with the HbA_1c result. This case report presents two cases of abnormally high HbA_1c in patients with Hb J using the high-performance liquid chromatography (HPLC) method and repeated value using the capillary electrophoresis (CE) method. The first case was a 26 years old female Malay patient, presenting at 25 weeks gestation with diabetes mellitus (DM). Her HbA_1c results from HPLC showed persistently high level (> 18.5%, > 179 mmol/mol) despite optimum diabetic control (fasting blood sugar (FBS) range 4.0–6.1 mmol/L). The second case was a 62-year-old female Malay with type 2 DM. Her HbA_1c results from HPLC was also persistently high (> 18.5%, > 1;79 mmol/mol) despite good diabetic control (FBS average 5.0–7.0 mmol/L). Both patients’ hemoglobin analysis reports were suggestive of Hb J. Repeated HbA_1c using CE were 6.0% (42 mmol/mol) and 8.1% (65 mmol/mol), respectively, and supported the presence of the Hb J variant peak. HbA_1c measurement in patients with a variant should be interpreted with caution to avoid misdiagnosis and mismanagement in these kinds of patients.

Discordantly high HbA1c may assist in diagnosing α-thalassemia but not diabetes: A case report

Glycated hemoglobin (HbA1c) is an important method for monitoring blood glucose and diagnosing diabetes. High‐performance liquid chromatography is more commonly used in the laboratory for the detection of HbA1c. Although HbA1c detected by high‐performance liquid chromatography is susceptible to abnormal hemoglobin, there are few reports that it is affected by α‐thalassemia. Previous reports have generally concluded that α‐thalassemia does not affect or lower HbA1c. Here, we report a case of discordantly high HbA1c inconsistent with fasting blood glucose. Finally, the patient was diagnosed with α‐thalassemia and insulin resistance. α‐Thalassemia might lead to a discordantly high HbA1c result, which could be attributed to elevated hemoglobin H. In this case, glycated albumin might accurately reflect the real average level of blood glucose. When finding discordant HbA1c, patients should be advised to undergo thalassemia and hemoglobinopathy screening by diabetologists/endocrinologists or primary care physicians to avoid a missed diagnosis of hematopathy.

Evaluation on the separated effect of 13 hemoglobin variants by a new automatic Hba1c analyzer

Objective

To evaluate the effect of a new type of automatic glycated hemoglobin analyzer on the separation of abnormal hemoglobin.

Methods

Samples diagnosed as hemoglobin variants by capillary electrophoresis and gene testing were selected, and HbA1c analyzer was used for separation and detection.

Results

A total of 13 hemoglobin variants in 40 samples could be separated from the normal peaks.

Conclusions

The variant mode of hemoglobin HbA1c can identify a variety of hemoglobin variants, and the type of variants can be preliminarily determined according to the retention time and characteristic peak shape of the variants.

Investigating the Reliability of HbA1c Monitoring for Blood Glucose Control During Late Pregnancy in Patients with Gestational Diabetes Mellitus (GDM) with and without β-Thalassemia Minor

INTRODUCTION

Patients with gestational diabetes mellitus (GDM) need strict blood glucose control to reduce the incidence of perinatal complications in the mother or infant. The purpose of this study was to investigate whether the glycated hemoglobin (HbA1c) values of GDM patients were affected by β-thalassemia minor and to subsequently discuss the limitations of HbA1c monitoring for blood glucose control.

METHODS

41 GDM patients with β-thalassemia minor were enrolled to serve as the study group. 93 GDM patients without thalassemia were randomly selected as a control group. Clinical data on the 134 mothers as well as their newborns were retrospectively analyzed. The blood glucose values of the participants at various times during the gestation period were compared between the groups, as were their HbA1c and ferritin levels and iron deficiency rates in late pregnancy (36-38 weeks of gestation). Pearson's coefficient was calculated to determine the correlations between HbA1c and ferritin in both the study and control groups.

RESULTS

The study and control groups did not show any significant differences in newborn birth weight, maternal age, maternal pre-pregnancy body mass index (BMI), gestational age, newborn sex, gravidity, and parity. The blood glucose values of the participants at different times during the gestation period also did not differ significantly between the study group and the control group. However, the late-pregnancy HbA1c level (5.23 ± 0.49%) and iron deficiency rate (12.19%) in the study group were significantly lower than those in the control group (5.42 ± 0.43% and 58.06%, respectively); P  < 0.05. Also, the late-pregnancy ferritin level in the study group (46.59 ± 18.03 ng/mL) was significantly higher than that in the control group (25.58 ± 11.42 ng/mL); P  < 0.05. In addition, a significant negative correlation was observed between HbA1c and ferritin in both the study group (R = - 0.459, P = 0.003) and the control group (R = - 0.358, P = 0.010).

CONCLUSIONS

The HbA1c level is affected by many factors. Using serum HbA1c values to monitor blood glucose in GDM patients with β-thalassemia minor may lead to a mistaken assumption of low blood glucose levels, so HbA1c may not be a suitable indicator for monitoring blood glucose in pregnant women, particularly GDM patients with β-thalassemia minor.

Effects of hemoglobin variants HbJ Bangkok, HbE, HbG Taipei, and HbH on analysis of glycated hemoglobin via ion-exchange high-performance liquid chromatography

BACKGROUND

To explore the effects of HbJ Bangkok, HbE, HbG Taipei, and α-thalassemia HbH on the results of HbA1c assessment using ion-exchange high-performance liquid chromatography (IE-HPLC).

METHODS

We enrolled five patients in which the results of the IE-HPLC HbA1c assay were inconsistent with the average levels of FBG. We performed hemoglobin capillary (Hb) electrophoresis using whole-blood samples. We also sequenced the genes encoding Hb using dideoxy-mediated chain termination and analyzed HbA1c using borate affinity HPLC (BA-HPLC) and turbidimetric inhibition immunoassay (TINIA).

RESULTS

Two patients had the HbJ Bangkok variant. Hb genotypes of these patients were β^41-42 /β^{J Bangkok} and β^N /β^{J Bangkok} , and the content of HbJ Bangkok was 93.9% and 52.4%, respectively. The remaining three patients had the following: HbE (β^N /β^E Hb genotype, 23.6% HbE content), HbG Taipei (β^N /β^{G Taipei} Hb genotype, 39.4% HbG Taipei content), and α-thalassemia HbH (6.1% HbH content, 2.8% Hb Bart's content). In the patients with β-thalassemia and HbJ Bangkok variants, the presence of the variants interfered with the results of HbA1c analyses using IE-HPLC and TINIA; in the remaining four patients, there was interference with the results of HbA1c IE-HPLC but not with the TINIA assay. There was no interference with BA-HPLC HbA1c results.

CONCLUSIONS

HbJ Bangkok, HbE, HbG Taipei Hb, and α-thalassemia HbH disease cause varying degrees of interference with the analysis of HbA1c using IE-HPLC. In these patients, we suggest using methods free from such interference for the analysis of HbA1c and other indicators to monitor blood glucose levels.

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.

Identification of haemoglobin New York by haemoglobin A1c measurement using the Sebia Capillarys 2 Flex Piercing system

Haemoglobinopathies may interfere with the haemoglobin A1c (HbA1c) measurement, leading to incorrect diagnosis and inappropriate treatment. It is essential that HbA1c assays are capable of identifying haemoglobinopathies. We report two cases of haemoglobin New York (HbNY) discovered through HbA1c analysis using capillary electrophoresis (Capillarys 2 Flex Piercing [C2FP], Sebia). We used these samples to evaluate the ability of three other HbA1c assays to identify this variant: ion-exchange high-performance liquid chromatography (Variant II Turbo [VII-T], Bio-Rad); boronate affinity high-performance liquid chromatography (Ultra2, Trinity Biotech) and immunoassay (Cobas c501 Tina-quant Generation 3, Roche Diagnostics). Each method was used for HbA1c assay of in samples from two cases of heterozygous haemoglobinopathy: β0-thalassemia/HbNY (Case 1) and HbA/NY (Case 2). Only the C2FP system detected HbNY (an additional peak appeared between HbA1c and HbA0). Clinical laboratories should be aware of the limitations of their HbA1c assay methods especially in geographic areas, where haemoglobinopathy prevalence is high.

Standardising HbA1c-based diabetes diagnosis: opportunities and challenges

Globally, the incidence of diabetes mellitus is rising at an alarming rate and has become a health crisis that threatens the economies of all nations. Therefore, diagnosing diabetes has become an important issue in the management of diabetes. Glycated hemoglobin (HbA1c) is now recommended as a means to diagnose diabetes, but its use still has limitations. In this article, the biology, measurement, standardization, and opportunities and challenges of the use of HbA1c to diagnose diabetes are reviewed. More specifically, its use in China and the Asian region is discussed in detail.