Evaluation of the Menarini/ARKRAY ADAMS A1c HA-8180V analyser for HbA1c

Pre-transplant HbA1c and risk of diabetes mellitus after kidney transplantation: a single center retrospective analysis

BACKGROUND

Post-transplant diabetes mellitus occurs in 10-40% of kidney transplant recipients and is associated with increased risk of developing cardiovascular diseases. Early identification of patients with a higher risk of developing diabetes could allow to take timely measures. However, no validated model exists to predict the risk of post-transplant diabetes mellitus.

METHODS

This retrospective study includes 267 adult patients who underwent kidney transplantation at the Antwerp University Hospital between January 2014 and August 2021. Post-transplant diabetes mellitus was diagnosed based on the American Diabetes Association definition at 3 months post-transplant. First, a logistic regression analysis was used to identify predictors for post-transplant diabetes mellitus. Second, criteria to identify patients with a high risk (> 35%) of developing post-transplant diabetes mellitus at 3 months were established.

RESULTS

At 3 months post-transplantation, 54 (20.2%) patients developed post-transplant diabetes mellitus. Univariable analysis showed that age, body mass index and HbA1c on the day of transplantation were associated with post-transplant diabetes mellitus. However, in a multivariable model with the same parameters, only HbA1c remained statistically significant. An absolute increase in HbA1c of 0.1% increases the odds for developing post-transplant diabetes mellitus by 28% (95% confidence interval 1.15-1.42). An HbA1c level ≥ 5.3% at transplantation, regardless of age or body mass index, is sufficient to identify patients with a post-transplant diabetes mellitus risk of ≥ 35% with a positive predictive value of 39% and a negative predictive value of 88%.

CONCLUSIONS

The HbA1c value at transplantation was the strongest predictor for post-transplant diabetes mellitus at 3 months post-transplant. Furthermore, at least in our population, a pre-transplant HbA1c of ≥ 5.3% can be used as an easy tool to identify patients at high risk of early post-transplant diabetes mellitus.

Analytical evaluation and quality assessment of the ARKRAY ADAMS A1c Lite HA-8380V for HbA1c

INTRODUCTION

ARKRAY ADAMS A1c Lite HA-8380V is a fully automated high- performance liquid chromatography system for the measurement of HbA1c. We aimed to evaluate its analytical performance using the Variant Mode.

METHODS

Carry-over, linearity, imprecision, trueness, interferences and comparison against ARKRAY ADAMS A1c HA-8180V and HA-8180T analyzers were studied.

RESULTS

Total CVs 0.93% (IFCC units), 0.63% (NGSP units) at low concentration and 1.01% (IFCC) 0.74% (NGSP), at high concentration. Mean difference with the target values was -0.44 mmol/mol (IFCC) -0.04% (NGSP). Carry-over, linearity and method comparison were excellent.The results were not affected in the range of total Hb 39-199 g/L, labile fraction 5.7%, carbamylated Hb 9.1% nor acetylated Hb 7.8%, effect of common variants was negligible.

CONCLUSIONS

the analyzer demonstrated very good analytical performances, according to the consensus criteria established for HbA1c; it is adequate for laboratories with medium-low workloads.

Analytical evaluation and quality assessment of the ARKRAY ADAMS A1c HA-8190V for Hb A1c

ARKRAY ADAMS A1c HA-8190V is a fully automated high-pressure liquid chromatography (HPLC) system for the measurement of HbA1c. The runtime is 58 s per sample in the Variant mode and 24 s per sample in the Fast mode. We evaluated the analytical performance of this analyzer in the Variant mode, to verify the quality of analysis, according to the consensus criteria established for this measurand. Reproducibility, trueness, carry-over, linearity, interferences and comparison with ARKRAY ADAMS A1c HA-8180V and HA-8180T analyzers were evaluated. Total CVs were 0.76% (IFCC units) 0.55 (NGSP units) at low HbA1c concentration and 0.85% (IFCC units) 0.68 (NGSP units) at high HbA1c concentration. Mean difference with the target values was -1.25 mmol/mol (-0.119%) and total error at medium level was 2.83% (IFCC units), 2.46% (NGSP units) Carry-over was 0%. Linearity was shown in the range 27-122 mmol/mol (4.6-13.3%). The results were not affected in the range of total Hb 59-199 g/L, labile fraction up to 5.5%, carbamylated up to Hb 6.3% nor acetylated Hb up to 5.3%. Method comparison demonstrated good concordance between the methods. The analyzer demonstrated a high analytical performance adequate for routine clinical use in laboratories with high workloads.

Evaluation of an Ion-Exchange HPLC Device for HbA1c Measurement

BACKGROUND

The ADAMS™ HA-8180V is the 8th generation of a fully automated ion-exchange HPLC system from ARKRAY, and the first to be released onto the US market. We evaluated the HA-8180V, for routine hemoglobin A1c measurement in comparison with the Roche Cobas c501, the Tosoh G8 analyzer for normal hemoglobin, and with the Trinity analyzer for hemoglobin variants.

METHODS

The analytical performance (linearity, precision, carryover, and sample stability) was assessed based on the Clinical and Laboratory Standards Institute (CLSI) and manufacturer guidelines. A comparison of the HA-8180V against two major analytical methods was performed for 100 whole blood samples. HA-8180V variant mode was also compared against the Trinity ultra2 A1c analyzer for 50 samples containing hemoglobin variants (HbC 14, HbS 14, HbD 12, and HbE 10).

RESULTS

The within-run and total CVs were <0.01 and 0.75% at low HbA1c concentration and 0.46 and 0.63% at high HbA1c concentration, respectively. Linearity was shown in the concentration range 3.4-18.1% HbA1c, carryover was 0.00%, and stability values were excellent. Method comparison demonstrated a high concordance between methods.

CONCLUSION

The eighth generation ADAMS HA-8180V A1c analyzer demonstrated high analytical performance adequate for routine clinical use.

Evaluation of the ARKRAY HA-8190V instrument for HbA1c

OBJECTIVES

Hemoglobin A_1c (HbA_1c) is a valuable parameter in the monitoring of diabetic patients and increasingly in diagnosis of diabetes. Manufacturers continuously optimize instruments, currently the main focus is to achieve faster turnaround times. It is important that performance specifications remain of high enough standard, which is evaluated in this study for the new ARKRAY HA-8190V instrument.

METHODS

The Clinical and Laboratory Standards Institute (CLSI) protocols EP-5, EP-9 and EP-10 were applied to investigate imprecision, bias and linearity. In addition potential interferences, performance in External Quality Assessment (EQA) and performance against the HA-8180V instrument in 220 clinical samples was evaluated.

RESULTS

The HA-8190V demonstrates a CV of ≤0.8% in IFCC SI units (≤0.6% National Glycohemoglobin Standardization Program [NGSP]) at 34 and 102 mmol/mol levels (5.3 and 11.5% NGSP) and a bias of -0.1 mmol/mol (-0.01% NGSP) at a concentration of 50 mmol/mol (6.7% NGSP), but with a significant slope as compared to target values. This results in a bias of -1.0 and 0.9 mmol/mol (-2.0 and 0.9% NGSP) at the 30 and 70 mmol/mol (4.9 and 8.6% NGSP) concentration level. Simulation of participation in the IFCC certification programme results in a Silver score (bias -0.1 mmol/mol, CV 1.1%). Interference in the presence of the most important Hb variants (AS, AC, AE, AD) and elevated HbA₂ and HbF concentrations is less than 3 mmol/mol (0.3% NGSP) at a concentration of 50 mmol/mol (6.7% NGSP).

CONCLUSIONS

Analytical performance of the HA-8190V is very good, especially with respect to precision and HbA_1c quantification in the presence of the most common Hb variants.

Capillarys 2 Flex Piercing: Analytical performance assessment according to CLSI protocols for HbA1c quantification

HbA_1c is used for monitoring diabetic balance. In this paper we report an assessment of the analytical performances of Capillarys 2 Flex Piercing (C2FP) for HbA_1c measurement using CE (Capillary Electrophoresis). CLSI (Clinical and Laboratory Standard Institute) protocols are used for the evaluation of apparatus performances: precision, linearity, method comparison, trueness and common interferences. HbA_1c CVs average in intra-assay was 1.6% between run imprecision CV ranged from 0.1 to 1.8%. The linearity was demonstrated between 4.7 and 15.0%. The comparison study revealed that Bland Altman plot mean difference was equal to -0.03 (CI 95% (-0.05 to -0.0003)) and Passing-Bablok regression intercept was -0.05, CI95%(-0.13 -  -0.05); slope: 1.00, CI95%[1.00-1.01]. A strong correlation (r > 0.99) was proved. No significant effects of hemoglobin variants were seen with CE on HbA_1c measurement. No problem related to sample-to-sample carry over was noted. No interferences of LA_1c and cHb were observed. CE allowed quantification of HbA_1c even at low level of total hemoglobin (40 g/L) in contrast to HPLC. Furthermore, this analyzer offered the opportunity of quantifying the HbA₂ simultaneously with HbA_1c . This evaluation showed that C2FP is a convenient system for the control of diabetes and the detection of hemoglobinopathies.

Methods, units and quality requirements for the analysis of haemoglobin A1c in diabetes mellitus

The formation of glycohemoglobin, especially the hemoglobin A_1c (HbA_1c) fraction, occurs when glucose becomes coupled with the amino acid valine in the β-chain of Hb; this reaction is dependent on the plasma concentration of glucose. Since the early 1970s it has been known that diabetics display higher values OF HbA_1C because they have elevated blood glucose concentrations. Thus HbA_1c has acquired a very important role in the treatment and diagnosis of diabetes mellitus. After the introduction of the first quantitative measurement OF HbA_1C, numerous methods for glycohemoglobin have been introduced with different assay principles: From a simple mini-column technique to the very accurate automated high-pressure chromatography and lastly to many automated immunochemical or enzymatic assays. In early days, the results of the quality control reports for HbA_1c varied extensively between laboratories, therefore in United States and Canada working groups (WG) of the Diabetes Controls and Complications Trial (DCCT) were set up to standardize the HbA_1c assays against the DCCT/National Glycohemoglobin Standardization Program reference method based on liquid chromatography. In the 1990s, the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) appointed a new WG to plan a reference preparation and method for the HBA_1c measurement. When the reference procedures were established, in 2004 IFCC recommended that all manufacturers for equipment used in HbA_1c assays should calibrate their methods to their proposals. This led to an improvement in the coefficient of variation (CV%) associated with the assay. In this review, we describe the glycation of Hb, methods, standardization of the HbA_1c assays, analytical problems, problems with the units in which HbA_1c values are expressed, reference values, quality control aspects, target requirements for HbA_1c, and the relationship of the plasma glucose values to HbA_1c concentrations. We also note that the acceptance of the mmol/mol system for HbA_1c as recommended by IFCC, i.e., the new unit and reference ranges, are becoming only slowly accepted outside of Europe where it seems that expressing HbA_1c values either only in per cent units or with parallel reporting of percent and mmol/mol will continue. We believe that these issues should be resolved in the future and that it would avoid confusion if mmol/mol unit for HbA_1c were to gain worldwide acceptance.

Evaluation of Bio-Rad D-100 HbA1c analyzer against Tosoh G8 and Menarini HA-8180V

Objectives

To evaluate the Bio-Rad D-100®, an HPLC analyzer for glycated hemoglobin (HbA_1c) determination, and to compare its performance with the Menarini HA-8180V® and Sysmex G8®.

Methods

Method comparison was performed according to Clinical and Laboratory Standards Institute (CLSI) EP9-A2 guidelines. We selected 100 samples from the routine laboratory workload and analyzed them in duplicate with the three analyzers. The imprecision study was performed according to CLSI EP5-A2 guidelines for both inter-assay and intra-assay variability. Bias was assessed with external quality control material. To establish linearity, CLSI EP6-A protocol was followed.

Results

Method comparison (95% confidence intervals in parentheses): D-100 vs G8: Passing-Bablok regression; y=0.973(0.963–0.983)×−0.07(−0.07−0.069); r=0.9989. Bland-Altman mean difference: −0.229%HbA_1c (−0.256: −0.202); Relative bias plot: D-100/G8 vs D100-G8 mean ratio=0.971(0.967−0.975). D-100 vs HA-8180V: Passing-Bablok regression; y=0.944(0.932–0.958)×−0.078(0.024−0.173); r=0.9989. Bland-Altman mean difference: −0.363%HbA_1c (−0.401: −0.325); Relative bias plot D-100/HA-8180V vs D100-HA-8180V mean ratio=0.955(0.952−0.958). Inter-assay coefficient of variation (CV): 0.81%. Intra-assay CV: 1.04% (low level), and 0.78% (high level). Bias against target value=2.332%. Linearity: r²=0.998 in the concentration range 4.4−13.9%HbA_1c. Carry-over: 0.0024%.

Conclusions

The Bio-Rad D-100 shows good correlation with G8 and HA-8180V. There is a small proportional systematic difference (2.7% and 5.6%, respectively) in both comparisons. Inter and intra-assay CVs are both lower than the lowest CV obtained in studies performed with D-100 and other instruments.

Glycated Serum Albumin and AGE Receptors

In vivo modification of proteins by molecules with reactive carbonyl groups leads to intermediate and advanced glycation end products (AGE). Glucose is a significant glycation reagent due to its high physiological concentration and poorly controlled diabetics show increased albumin glycation. Increased levels of glycated and AGE-modified albumin have been linked to diabetic complications, neurodegeneration, and vascular disease. This review discusses glycated albumin formation, structural consequences of albumin glycation on drug binding, removal of circulating AGE by several scavenger receptors, as well as AGE-induced proinflammatory signaling through activation of the receptor for AGE. Analytical methods for quantitative detection of protein glycation and AGE formation are compared. Finally, the use of glycated albumin as a novel clinical marker to monitor glycemic control is discussed and compared to glycated hemoglobin (HbA1c) as long-term indicator of glycemic status.

Evaluation of enzymatic BM Test HbA1c on the JCA-BM6010/C and comparison with Bio-Rad Variant II Turbo, Tosoh HLC 723 G8, and AutoLab immunoturbidimetry assay

BACKGROUND

A novel enzymatic HbA1c assay was introduced for use in an automated chemistry analyzer. With this unique method, HbA1c and plasma glucose can be measured from the same EDTA tube. We evaluated the analytical performance of this enzymatic HbA1c assay in a JCA-BM6010/C analyzer and compared the HbA1c values with the results from other widely used methodological instruments.

METHODS

The imprecision, linearity, carry-over and concordance rate of the enzymatic HbA1c test (BM Test HbA1c) using the JCA-BM6010/C analyzer were evaluated. Three hundred and seventy-seven specimens with HbA1c concentrations from 16 to 133 mmol/mol were used for a comparison study with two high performance liquid chromatography methods: Variant II Turbo and Tosoh HLC 723 G8 and the AutoLab Hemoglobin A1c immunoturbidimetry reagent using a Hitachi 7600-110. Forty specimens were used for the glucose method comparison.

RESULTS

The HbA1c coefficients of variation of the within-run imprecision for low and high levels were 0.6% and 0.4%, respectively. The linearity of the BM Test HbA1c using the JCA-BM6010/C analyzer was excellent in the range between 31 mmol/mol and 143 mmol/mol. The carry-over rate was 0.2%. The relationships between the BM test and the other three methods were 0.916×Tosoh G8+3.644, r=0.986; 0.887×Bio-Rad Variant II+1.896, r=0.972; and 0.941×AutoLab+4.532, r=0.977. The concordance rates using a cut-off of 48 mmol/mol were 91.5% with Tosoh G8, 82.8% with Bio-Rad Variant II, and 91.0% with AutoLab. The simultaneously assayed plasma glucose with HbA1c was 1.002×Routine plasma glucose+0.625, r=1.000 CONCLUSIONS: The enzymatic BM Test HbA1c in the JCA-BM6010/C analyzer showed excellent precision and linearity, and a minimal carry-over rate. The simultaneously assayed plasma glucose analysis showed good performance.

A history of HbA1c through Clinical Chemistry and Laboratory Medicine

HbA(1c) was discovered in the late 1960s and its use as marker of glycemic control has gradually increased over the course of the last four decades. Recognized as the gold standard of diabetic survey, this parameter was successfully implemented in clinical practice in the 1970s and 1980s and internationally standardized in the 1990s and 2000s. The use of standardized and well-controlled methods, with well-defined performance criteria, has recently opened new directions for HbA(1c) use in patient care, e.g., for diabetes diagnosis. Many reports devoted to HbA1c have been published in Clinical Chemistry and Laboratory Medicine (CCLM) journal. This review reminds the major steps of HbA(1c) history, with a special emphasis on the contribution of CCLM in this field.

Comparison of Arkray/ELITech ADAMS HA-8180V with Bio-Rad Variant, II Turbo2.0 and Tosoh Bioscience HLC-723G8 for HbA1c determination

OBJECTIVE

This study aimed to evaluate a new ion-exchange HPLC system to measure hemoglobin A1c (HbA1c) in comparison to two other widely used HPLC systems.

METHODS

Analytical performance and hemoglobin variants detection was assessed on the new Arkray/ELITech ADAMS HA-8180V, in parallel to Bio-Rad Variant II Turbo2.0 and Tosoh Bioscience HLC-723G8. A method comparison and concordance for the classification of patients according to the American Diabetes Association (ADA) categories was performed using kappa test.

RESULTS

ADAMS HA-8180V demonstrated excellent within-run imprecision (0%) and between-run imprecision: ≤1.21% using blood sample and ≤0.94% using quality controls. Method comparison of ADAMS HA-8180V with the two other systems yielded very high coefficient correlation (r > 0.995). A very good agreement (kappa value ≥0.81) was observed between methods for the classification of patients according to the ADA categories. In addition, all systems were able to detect the presence of most classical variants such as HbC, HbS, HbD, and HbE.

CONCLUSION

The Arkray/ELITech ADAMS HA-8180V demonstrated high analytical performance similar to previous systems such as Biorad(TM) Variant II Turbo 2.0 and Tosoh Bioscience HLC-723G8. The three systems allow a high-quality HbA1c measurement and appeared interchangeable for diabetes diagnosis or for the therapeutic monitoring of patients without hemoglobin variants.

Haemoglobin A1c: Historical overview and current concepts

Since the discovery of the relation between increased concentrations of fast haemoglobin fractions in patients with diabetes mellitus compared to concentrations in subjects without diabetes mellitus by Samuel Rahbar and co-workers in 1969, glycated haemoglobin A1c (HbA1c) has become a "gold standard" for glucose management in patients with diabetes mellitus. Recently, HbA1c has been advocated as a diagnostic marker for diabetes mellitus, which further underlines the importance of HbA1c. There are currently more than 30 methods available on the market with an analytical performance ranging from poor to state of the art. This review describes the biochemistry of HbA1c and the concepts of analytical and biological variation with respect to the measurement of HbA1c. Subsequently, aspects regarding the discovery of HbA1c are described. In addition, an overview is given on the assays methods that are currently available for the measurement of HbA1c. Finally, recommendations for the minimally required analytical performance characteristics of the current HbA1c assays are presented.