HbA1c Measurement Methods Research Articles

A Comparative Evaluation of HbA1c Measurement Methods and Their Implications for Diabetes Management.

In this study, we assessed the correlations between hemoglobin A1c (HbA1c) measurements obtained using three different diagnostic methods, namely reversed-phase cation-exchange chromatography, high-performance liquid chromatography, and lateral flow immunoassay (LIFA) with an AnyLab F instrument. HbA1c levels measured with the AnyLab F instrument and those measured with the HA8190V, HA8180, and D100 instruments were strongly correlated. High R-square values and low p-values indicated significant and reliable correlations, supporting the clinical interchangeability of these methods. Notably, demographic and clinical analyses revealed uniform HbA1c levels across age groups, suggesting minimal age-related variations in HbA1c levels in the cohort. This finding has implications for diabetes management strategies across different age groups, emphasizing the versatility of the AnyLab F instrument. Overall an average HbA1c level of 7.857% among diabetes mellitus-diagnosed participants suggests moderately elevated HbA1c levels, underscoring the need for improved diabetes management. Younger individuals exhibited lower HbA1c levels, potentially owing to heightened awareness and treatment plan adherence. Conversely, older adults had higher HbA1c levels, likely influenced by age-related changes and comorbidities. Larger sample sizes and a comprehensive evaluation of various measurement principles are needed to strengthen the findings herein. Additionally, exploring additional biomarkers and assessing LIFA performance in larger sample sets will advance the clinical utility of HbA1c measurements.

Comparison of three different HbA1c measurement methods – the Atellica®CH930, Capillary 3 Tera, and BioRad Variant Turbo II

Aim HbA1c measurement is very useful for the follow-up and detection of glycemic disorder, since it is easier and faster test and is independent of the patient's fasting status. In this study, we aimed to perform the comparative evaluation of 3 different methods for HbA1c measurement including capillary electrophoresis, immunoturbidimetric assay and high-performance liquid chromatography-HPLC. Materials and methods This study comprised 134 leftover whole blood samples obtained from the subjects submitted for routine HbA1c testing. All blood samples were collected in EDTA-containing vacutainer tubes. The HbA1c levels were measured simultaneously using three different methods. Bias estimation, method agreement and concordance between the pairwise methods comparisons were evaluated by Bland–Altman plot and Passing–Bablok regression test. Results HbA1c levels ranged from 3.8% to 13.4% and measured by three different methods to make the comparison. The median values of samples based on immunoturbidimetric method (6.05%, IQR = 1.80) were higher than capillary electrophoresis method (5.90%, IQR = 1.80) and HPLC (5.85%, IQR = 1.80) method. The study group was classified into three subgroups based on the HbA1c levels measured with the HPLC method: Group 1 (n = 57) was composed of subjects with HbA1c levels less than 5.7%, Group 2 (n = 35) had HbA1c levels between 5.7% and 6.4%, Group 3 (n = 42) had HbA1c levels equal and more than 6.5%. Conclusion To our knowledge, there is no study evaluating the HbA1c measurement on the Atellica® CH 930 Analyzer. We compared the Atellica®CH930 Analyzer with both HPLC and capillary electrophoresis. The Atellica®CH930 Analyzer showed acceptable performance and a strong correlation with both mentioned methods.

Towards noninvasive and fast detection of Glycated hemoglobin levels based on ECG using convolutional neural networks with multisegments fusion and Varied-weight

Glycated hemoglobin A1c (HbA1c) is regarded as a gold standard to evaluate long-term blood glucose control, and it is also a crucial metric in diabetes screening, diagnosis, and management. However, thus far, the HbA1c measurement methods are invasive and painful. Considering that HbA1c levels are associated with cardiovascular autonomic neuropathy, in this paper, a novel Electrocardiogram (ECG)-based approach was presented for noninvasive and fast detection of HbA1c levels using 60-second, single-lead ECG waveform. For this purpose, a total of 317,105 ECG datasets encompassing 370 patients with diabetes were obtained using wearable devices. Furthermore, the ECG preprocessing was based on autocorrelation analysis. The convolutional neural networks with multisegment fusion and varied-weight (CNN-MFVW) were proposed to achieve ECG feature extraction and HbA1c detection. The results showed that the average accuracy, precision, recall, and F1-score of the proposed algorithm were 0.9015, 0.9051, 0.8991 and 0.9013 respectively. Moreover, the area under the curve (AUC) was up to 0.9899, which was higher than other algorithms of conventional CNN and CNN-LSTM. Therefore, we conclude that the proposed approach for noninvasive and fast detection of HbA1c levels has potentials in practical applications.

Impact of heterozygous hemoglobin E on six commercial methods for hemoglobin A1c measurement

Background This study examined the impact of heterozygous HbE on HbA1c measurements by six commonly used commercial methods. The results were compared with those from a modified isotope-dilution mass spectrometry (IDMS) reference laboratory method on a liquid chromatograph coupled with tandem mass spectrometer (LC-MS/MS). Methods Twenty-three leftover samples of patients with heterozygous HbE (HbA1c range: 5.4–11.6%), and nineteen samples with normal hemoglobin (HbA1c range: 5.0–13.7%) were included. The selected commercial methods included the Tina-quant HbA1c Gen. 3 (Roche Diagnostics, Basel, Switzerland), Cobas B 101 (Roche Diagnostics, Basel, Switzerland), D100 (Bio-Rad Laboratories, Hercules, CA, USA), Variant II Turbo HbA1c 2.0 (Bio-Rad Laboratories, Hercules, CA, USA), DCA Vantage (Siemens Healthcare, Erlangen, Germany) and HbA1c Advanced (Beckman Coulter Inc., Brea, CA, USA). Results With the exception of Cobas B 101 and the Variant II Turbo 2.0, the 95% confidence intervals of the Passing–Bablok regression lines between the results from the six commercial methods and the IDMS method overlapped. The latter suggested no statistically significant difference in results and hence no impact on HbA1c result despite the presence of heterozygous HbE. The method of Cobas B 101 gave positive bias at the range of concentrations examined (5.4–11.6%), while that of Variant II Turbo 2.0 gave positive bias at concentrations up to approximately 9.5%. The finding of significant positive bias in the methods of Cobas B 101 and Variant II Turbo 2.0 agrees with the observations of some previous studies, but is contrary to manufacturer’s claim indicating the absence of interference by heterozygous HbE. Our results also clearly showed the impact of heterozygous HbE across a fairly broad measurement range using a laboratory method (the Variant II Turbo 2.0). Laboratory practitioners and clinicians should familiarize themselves with prevailing hemoglobin variants in the population they serve and select the appropriate methods for HbA1c measurement.

Strong correlation and high comparability of capillary electrophoresis and three different methods for HbA1c measurement in a population without hemoglobinopathy

The present study aimed to investigate the comparability of capillary electrophoresis (CE) and three different methods for HbA1c measurement. The 270 whole blood samples with normal hemoglobin profiles were analyzed for HbA1c values by the Roche turbidimetric inhibition immunoassay (TINIA), the Mindray enzymatic assay (EA), the Arkray high-performance liquid chromatography (HPLC) in comparison with the Sebia CE. The within-laboratory coefficient of variation of all four methods was within the accepted goal (<2%), showing good performance of all of these methods. Pairwise comparisons of HbA1c values obtained by CE and other methods were determined in both total group and subgroups (HbA1c levels of <6.5%, 6.5–8% and >8%). Mean differences of HbA1c values in all groups were very small in which the mean HbA1c value measured by EA was lower while those by TINIA and HPLC were higher than that of CE. The majority of different values were within the limits of agreement in Bland-Altman analysis, indicating good agreement between CE and the others. Less than 5% of percentage differences were out of the total allowable error limit in all groups, showing that differences of HbA1c values between CE and other methods were not clinically significant. Pairwise comparisons of HbA1c values of CE and the others in Passing-Bablok regression and Spearman rank correlation studies displayed high concordance and strong correlation in all groups. In conclusion, the present study showed strong correlation, high comparability and consistent results for HbA1c measurement between capillary electrophoresis and the other three different methods.

Comparison of HbA1c measurement methods between automatic boronate affinity point of care testing and high-performance liquid chromatography

Background: This study aimed to assess the comparison between two HbA1c analyzers, Alere Afinion AS100, a boronate affinity based point of care testing (POCT), and High-Performance Liquid Chromatography (HPLC) based analyzer Bio-Rad Variant II Turbo HbA1c kit-2.0 as reference method.Methods: This study involved 120 samples of peripheral K3EDTA whole blood sent to Clinical Pathology Laboratory of Cipto Mangunkusumo National Hospital for HbA1c measurement. Based on reference method, 40 samples with HbA1c ≤ 6.4%, 40 samples with HbA1c &gt; 6.4%, and 40 samples with variant hemoglobin or hemoglobinopathy were included. Precision and accuracy of both analyzers were assessed using control materials. The goodness of fit between these methods were assessed by Bland-Altman plot and Passing-Bablok regression test. Results were compared to National Glycohemoglobin Standardization Program (NGSP) recommendations.Results: Reference method had total error (TE) ranging from 3.15% to 4.9%, while Afinion ranged from 2.16% to 3.24%. Both methods correlated well with Passing-Bablok regression showing no proportional or systematic differences. Linearity between tests was proven by Cusum test value of p &gt; 0.05. Bland-Altman plot yielded 91.74% goodness of fit. No significant differences were observed in hemoglobinopathy and variant hemoglobin analysis of HbA1c.Conclusion: Afinion was precise, accurate, and linear to HPLC reference method. Both methods exhibited no systematic or proportional differences. Despite Bland-Altman plot of less than 95% goodness of fit, no clinically significant result was found based on NGSP criteria.

New HPLC instrument performance evaluation in HbA1c determination and comparison with capillary electrophoresis

Glycated hemoglobin (HbA1c) measurement provides the most important medium to long-term marker of time-averaged glycemic status. Its relationship to clinical outcome in diabetes has been convincingly demonstrated for both type 1 and type 2 diabetes. The main HbA1c measurement methods for clinical routine are as follows: ion-exchange chromatography; affinity chromatography, capillary electrophoresis, immunoassay and enzymatic methods. In this study, we evaluated the analytical performances of a new HPLC instrument (Tosoh HLC-723 G11 in the VAR mode) in HbA1c analysis and compared it with a capillary electrophoresis instrument (Sebia Capillarys 2 Flex Piercing). HbA1c analysis was performed in parallel by both methods for 250 samples randomly chosen from healthy and diabetic subjects at ‘Tor Vergata’ University Hospital of Rome. Tosoh HLC-723 G11 showed good reproducibility for 10 days both in quality controls and in samples analyzed (%CV < 2%). We found good linearity for HbA1c values ranging from 15 mmol/mol (3.5%) to 178 mmol/mol (18.5%), with a correlation coefficient R2 = 1. In a comparison between Tosoh HLC-723 G11 and Capillarys 2FP a good correlation (r = 0.99) was found; however, Tosoh HLC-723 G11 showed higher values in the low range of HbA1c and lower in the high range (Tosoh HLC-723 G11 = 4.3043 + 0.913 Capillarys 2FP; p < 0.001). Tosoh HLC-723 G11 showed good repeatability, reproducibility, accuracy and automated simplicity, and it seemed suitable for routine use in clinical chemistry laboratories.

Evaluation of Accuracy, Precision and Agreement of Five Hba1c Measurement Methods with HPLC Reference Method

Background and Objective: The current challenge of diabetes mellitus is to prevent its complications. These complications are directly associated with hyperglycemia in diabetics. The HbA1c measurement is essential for long-term glycemic control. Synchronization of HbA1c measurement is important in order to avoid discrepancies between results reported by laboratories. This study aimed to evaluate the accuracy, precision and agreement of five HbA1c measurement methods with HPLC reference method. Methods: HbA1c levels of 55 samples were measured using six methods of microcapillary electrophoresis (Sepia), enzymatic method (Pishtaz Teb), immunoturbidometry (Pars Azmoon), boronate affinity (Nycocard), immunofluorescence (ichroma) and Tosoh G8 HPLC. Results: The five tested methods showed a good agreement with the HPLC method with correlation coefficient of less than 95%. Regression testing of HPLC method and other methods showed slope of 0.99 (P<0.05) for Sebia, 1.02 (P<0.05) for Pishtaz Teb, 0.79 (P<0.05) for Pars Azmoon, 0.82 (P<0.05) for Nycocard and 0.89 (P<0.05) for ichroma. Average inaccuracy for the Sebia, Pishtaz Teb, Pars Azmoon, Nycocard and ichroma in comparison with the HPLC reference method were -0.09, -0.004, -0.75, -0.79 and -0.78, respectively. Conclusion: The Sebia microcapillary method and Pishtaz teb enzymatic method have appropriate accuracy and precision. Therefore, these methods can be used as alternatives to the HPLC method for HbA1c measurement. Other methods such as Pars Azmoon, Nycocard and ichroma have significant shortcomings in terms of accuracy.

Influence of different methods for measuring HbA1c on health checkups in a rural town in Hokkaido, Japan.

Using data on health checkups performed in one Japanese town, we investigated the effect on health checkups of the methods used to measure hemoglobin A1c (HbA1c). The study included 337 participants undergoing health checkups at two facilities. At facility 1, HbA1c was measured by high-performance liquid chromatography (HPLC) in 2012 and by immunoassay (IA) in 2013, while at facility 2, HbA1c was measured by HPLC in both years. At facility 1, the mean HbA1c was significantly decreased from 2012 to 2013 (5.83 vs 5.50%, respectively; P<0.001), although the mean fasting plasma glucose (FPG) was significantly increased from 2012 to 2013 (91.7 vs 95.2mg/dL, respectively; P=0.02). Of the 202 participants at facility 1, 97 who had an HbA1c of ≥5.6% in 2012 had an HbA1c of <5.6% in 2013. At facility 2, the mean HbA1c marginally increased, while there were similar FPG levels in bothyears. An additional study of single blood samples from 27 healthy participants who were tested at the same facility using both HPLC and IA found that the mean HbA1c was significantly lower for IA than for HPLC (5.19 vs 5.50%, respectively; P<0.001). In summary, we found a substantial decrease in the mean HbA1c and the prevalence of impaired glucose tolerance and diabetes mellitus in study participants who underwent health checkups for two consecutive years when different methods were used to measure HbA1c. The lack of standardization of HbA1c measurement methods may have a large effect on health checkups.

Glycated Hemoglobin Detection in Clinical Blood Samples by Using CMOS Poly-silicon Sub-micron Wire Biosensor

This paper presents hemoglobin (Hb) and glycated hemoglobin (HbA1c) in clinical blood samples detection by a poly-silicon sub-micron wire (poly-Si SW) biosensor. HbA1c examination has been a better method in long-term diabetes monitoring without day-to-day glucose level fluctuations. Currently, HbA1c test need to be performed in laboratory or hospital because of complicated operation and the need of well-trained operator. This limits its applications in homecare application and resource limited area. The sensing results of poly-Si SW were compared to the standard Hb and HbA1c measurement methods and showed comparable results. Compared with conventional examination methods, using CMOS poly-Si SW biosensor can economize the cost of diagnoses and easily integrate with different functional systems. Based on our previous results, our work could potentially be applied for next generation healthcare application.

A high-throughput method for measurement of glycohemoglobin in blood samples utilizing laser-accelerated proteolysis and MALDI-TOF MS.

Glycosylated hemoglobin A1c (HbA1c) is a useful marker for the diagnosis of diabetes mellitus. Commercial column separation methods for HbA1c measurement were lacking throughput and sometimes interfered with hemoglobin variants. In this work, we developed a high-throughput and specific method for HbA1c by quantitative measurement of N-terminal peptides (NT method). Two thousand specimens could be measured in 8 h. The high-throughput was achieved by using a fast analysis of matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) and an efficient proteolysis accelerated by laser irradiation. An intensity ratio of glycosylated to non-glycosylated hemoglobin N-terminal peptides was used to calculate the HbA1c level in blood. Interference from Hb variants of N-terminal peptides could be excluded by a highly accurate mass selection. The coefficient of variation (CV) of intra-assay precision was 9.8 and 9.9%, respectively. The CVs of inter-assay precision over 20 days were 9.1 and 8.4%, respectively. Measurement results were well correlated with the commercially available column method (r = 0.995). The NT method is promising for large-scale screening for diabetes mellitus among people.

The interference by HbF on HbA1c (BM Test HbA1c) measurement in enzymatic method.

High performance liquid chromatography and immunological and enzymatic methods are known as the methods for HbA1c measurement. However, the differences in the principles of the methods may cause slight discrepancies, which become problems especially in the regions where hemoglobinopathies that have high HbF concentrations are commonly seen. In this report, we discuss the effect of HbF on the HbA1c measurement by the enzymatic method (BM Test HbA1c) which can be applied to automatic analyzer of high sample throughput. Thirty-five samples (HbF concentration: between 1.4 and 90.1%) and 68 samples (HbF concentration: <1.0%) were analyzed by high performance liquid chromatography (Tosoh G8) and BM Test HbA1c. The results by BM Test HbA1c were compared with those by the high performance liquid chromatography and International Federation of Clinical Chemistry reference method. The high and positive correlation coefficient was demonstrated between the enzymatic and International Federation of Clinical Chemistry methods for the samples with normal HbF concentration. The samples with high HbF concentration exhibited high and positive correlation coefficient, although the figure is lower than that of the normal HbF concentration group. BM Test HbA1c revealed a high and positive correlation with high performance liquid chromatography and International Federation of Clinical Chemistry reference methods. However, the HbA1c values by BM Test HbA1c and high performance liquid chromatography method were lower than those by International Federation of Clinical Chemistry reference method when the HbF concentration was high. BM Test HbA1c had some deviation from the International Federation of Clinical Chemistry reference method, while no significant interference was seen when the HbF values were less than 15%. When HbF is higher than 15%, however, the interpretation of HbA1c by BM Test may require some special consideration.

Comparative evaluation of three different methods for HbA1c measurement with High-performance liquid chromatography in diabetic patients.

Background:The global prevalence of diabetes mellitus is increasing rapidly. Measurement of glycated hemoglobin, predominantly HbA1c, is fundamental to the management of patients with diabetes. HbA1c is used to monitor long-term glycemic control, adjust therapy, assess the quality of diabetes care and predict the risk for the development of complications. While HbA1c is the standard method for long-term glycemic control in diabetic patients, there are different methods for measurement of HbA1c and all laboratories do not use the reference method (high-performance liquid chromatography [HPLC]). The objective of this study is comparison of three different methods with HPLC to find out which method has an acceptable concordance and correlation with the reference method.Materials and Methods:Fifty-eight diabetic patients were assessed in this study. The blood sample of each patient was checked with Diazyme (enzymatic assay), Nycocard (boronate-affinity binding) and Biosystem (micro column chromatography). The values of HbA1c of each method were compared with the Knauer-HPLC results.Results:The means of the differential values between each method and HPLC in the ANOVA test are as follows: M = 1.8, SD = 1.09 for Nycocard-HPLC; M = 1.5, SD = 1.08 for biosystem-HPLC; M = 1.3, SD = 1.2 for Diazyme-HPLC. Pearson's correlation coefficient between HPLC and Nycocard; 0.76, HPLC and Diazyme; 0.75 and between HPLC and Biosystem was 0.68. Linear regression parameters for each method with HPLC were also determined.Conclusion:Diazyme had a better performance and showed a greater concordance with HPLC among others, although it was not an ideal alternative for HPLC.

HbA1c: how do we measure it and what does it mean?

Description of recent developments in the standardization of HbA1c measurement and interpretation of HbA1c results. HbA1c is extensively used in the management of patients with diabetes. The two major schemes to standardize HbA1c produce values that differ substantially. A prospective, multinational study revealed a linear correlation between HbA1c and average blood glucose. Some, but not all, assay methods are able to accurately measure HbA1c in individuals with common hemoglobin variants. Progress in standardization of methods for HbA1c measurement has significantly reduced variation among different methods. The improved accuracy could allow HbA1c to be used for screening and diagnosis of diabetes. A consensus document recommends that HbA1c be reported in both NGSP (%) and IFCC (mmol/mol) units. HbA1c results can be translated into estimated average glucose (eAG), which could be reported in addition to HbA1c.