Tosoh G8 Research Articles

Mobile Health for Diagnosis-PixoTest HbA1c POCT System

Glycated hemoglobin (HbA1c) has been recommended as a standard indicator of long-term glycemic control for diabetic and non-diabetic patients, within the in vitro diagnostic (IVD) industry that is focused on the development of point-of-care (POC) methods with improved operational convenience and shorter measurement time. In this study, we evaluated the measurement accuracy performance of a recently commercialized POC HbA1c analyzer, PixoTest POCT System (iXensor Co., Ltd.) that is portable, intuitive and wireless data transmission enabled. For PixoTest POCT accuracy evaluation, TOSOH G7 Analyzer (TOSOH Bioscience GmbH) was used as a reference method and performed in accordance with CLSI EP 09-A3 guidelines. This study enrolled one hundred and twenty (120) subjects from three clinical sites (40 subjects each), administered through nine (9) trained operators (total) performed under manufacturer’s protocol using three reagent lots per blood sample (capillary & venous). Linear regression, bias plot and other statistical analyses were extrapolated from the test data. Passing-Bablok regression analysis of the data between PixoTest POCT System and TOSOH G7 Analyzer with the venous blood showed a slope of 1.03 and an intercept of − 0.1 and a correlation coefficient of 0.99. The results for capillary blood showed a slope of 1.01 and an intercept of − 0.04 and a correlation coefficient of 0.99. The PixoTest POCT System’s performance is similar to TOSOH G7 Analyzer in accuracy and linearity. Therefore, the system’s HbA1c test capability is ideal for the management of chronic disease, as a user convenient and efficient POC solution.

1283-P: PTS Diagnostics A1CNow+: A Valuable Tool in a Value-Based World

Background: Value-based medicine is a new healthcare model to shift physician focus from the quantity of services and revenue generated to quality and value of healthcare provided. The basis for this model is the idea of the right care for the right patient in the right environment at the right time, also known as Patient Centered Medical Home (PCMH). Point-of-care A1C testing can maximize patient and provider engagement by obtaining the results in real-time which allows for effective communication, healthy discussions, and improved healthcare. This study evaluated the accuracy of A1CNow+ as a tool to assist with PCMH for diabetes management. Method: Blood was collected from PTS employees. A1C values ranged from 4.4 - 12.4% A1C for a total of 90 data points. Capillary blood was tested on the PTS Diagnostics A1CNow+ system while venous blood was tested at PTS Diagnostics on the Tosoh G8 and Roche Cobas® Integra® 400 Plus as clinical laboratory (CL) comparators. For reference, venous blood was tested at LabCorp on the Roche Cobas c513. Deming regression analysis was used to evaluate accuracy and paired differences to measure bias. Clinical risk was assessed using A1C clinical cut points of < 5.7, 5.7 - 6.4, and ≥ 6.5% A1C. Fisher’s exact test was used to assess differences amongst methods. Results: Average paired percent bias was -0.83% for the A1CNow+ and +0.17% for the CL analyzers. Slopes were 0.92 and 0.93 (p=0.35) and intercepts were 0.42 and 0.44 (p=0.098) for the A1CNow+ and CL, respectively. Clinical risk agreement was 89% for A1CNow+ and 97% for CL analyzers (p=0.08). Conclusion: The A1CNow+ was shown to be as accurate as the clinical lab in measuring A1C. Risk analysis showed no statistical difference between the CL and A1CNow+ in classifying A1C clinical cut points. The A1CNow+ is a valuable tool to help meet the goals of the Quadruple Aim which seeks to improve the health of the population, improve the patient experience of care, improve the provider experience of giving care, and reduce the cost of healthcare in a value-based world. Disclosure C.J. Szablowski: Employee; Self; PTS Diagnostics. K. Davis: None. J.H. Anderson: Board Member; Self; Generex Biotechnology Corp., VoCare. Consultant; Self; Know Labs. Employee; Self; PTS Diagnostics. Other Relationship; Self; Lilly Diabetes.

1312-P: Admission Plasma Glucose and HbA1c in Emergency Hospital Admissions by Ethnicity

Introduction: As HbA1c is now widely used for the diagnosis of diabetes with WHO cut-off ≥ 48 mmol/mol/6.5%, it is debatable whether the value should vary by ethnicity. Aim: This study compares plasma glucose and HbA1c in white European WE, South Asian SA, unknown/other U and Afro-Caribbean AC people admitted as an emergency. Methods: Electronic patient records were interrogated over 1 year (2014/5) for a clinical audit, CARMS-12031R. Glucose was measured on wards with meters/gas machines or the laboratory along with HbA1c on Tosoh G8 HPLC analysers if haemoglobin normal. Results: There were 30,664 people of whom 22,045 (72%) had glucose recorded and 2,083 (7%) HbA1c. 1,904 (6%) had both glycaemic markers and were aged 64 (50-78) years, median (IQ range); 839 (44%) female; 560 (29%) prior diabetes diagnosis; 1,405 (74%) WE, 296 (16%) SA, 112 (6%) U and 91 (5%) AC. Glucose was 7.4 (5.8-10.6), 8.6 (6.2-12.3), 8.1 (5.9-10.7), 7.0 (5.9-11.6) mmol/L and HbA1c 42 (37-55), 50 (41-70), 42 (38-60), 46 (39-70) mmol/mol/6.0 (5.5-7.2), 6.7 (5.9-8.6), 6.0 (5.6-7.6), 6.4 (5.7-8.6)%, respectively. HbA1c was higher relative to glucose in SA and AC compared to WE and U, p<0.001. Conclusions: Haematological differences related to red blood cell turnover may account for the variance; this should be recognised by those involved in producing protocols/guidelines for diagnosis. More research is required on using HbA1c to confirm undiagnosed diabetes in admissions. Disclosure S.E. Manley: None. R. Susarla: None. R.A. Round: None. P. Nightingale: None. J.A. Williams: None. I.M. Stratton: Consultant; Self; Novo Nordisk A/S. Research Support; Self; Bayer AG, Boehringer Ingelheim International GmbH. J. Webber: None. G. Gkoutos: None. W. Hanif: Advisory Panel; Self; Boehringer Ingelheim International GmbH. Consultant; Self; Novo Nordisk A/S. Research Support; Self; AstraZeneca, Janssen Diagnostics, Sanofi. Speaker's Bureau; Self; AstraZeneca, Novartis AG, Novo Nordisk A/S. G. Roberts: None. S. Ghosh: Advisory Panel; Self; Abbott. Other Relationship; Self; Mylan.

Comparative analysis of glycosilated hemoglobin results obtained from two analyzers: Variant II Turbo and Tosoh G8

Comparative analysis of glycosilated hemoglobin results obtained from two analyzers: Variant II Turbo and Tosoh G8

Visual Inspection of Chromatograms Assists Interpretation of HbA1c: A Case Report

A 58-year-old woman presented with elevated fasting plasma glucose found in a medical check-up. She was asymptomatic, and clinical examination was normal apart from slight sclera jaundice. The 75-g oral glucose tolerance test showed fasting plasma glucose of 5.6 mmol/L and 2-h postprandial plasma glucose of 5.98 mmol/L. The HbA1c taken at the same visit was 2.0% (value unavailable in International Federation of Clinical Chemistry and Laboratory Medicine [IFCC] units) (assayed by the Tosoh G8 analyzer); on retesting, it was 3.6% (16 mmol/mol) (assayed by the Bio-Rad D-10 TM analyzer). The synchronous glycated albumin was 11.59%. Her other blood results were as follows: …

Point-of-Care HbA1c—A Case for Diabetes Screening and Diagnosis

Background: Hemoglobin A1C (A1C) is routinely used to screen, diagnose, and monitor diabetes. A1C is the desired tool to assess glycemic status as it reflects 90 days of glycemic control and does not require fasting. Point-of-care (POC) A1C offers rapid turnaround enabling direct patient engagement. POC A1C tests are indicated for monitoring, but not screening or diagnosis, due to perceived inaccuracy and imprecision. To counter this impression, we evaluated the performance of two POC A1C analyzers relative to the clinical laboratory (CL). Method: Blood from 48 subjects was collected with A1C values from 4.8-12.0% A1C. Capillary blood was analyzed on the PTS Diagnostics A1CNow®+ system and Siemens DCA Vantage® while venous blood was tested at external labs on the Tosoh G8 and Roche Cobas® c513 as CL comparators. For reference, venous blood was analyzed on the Roche Cobas Integra® 400 plus. Regression analysis was used to evaluate accuracy and paired differences to measure bias. Clinical risk was calculated using A1C category cut points of < 5.7, 5.7-6.4, and ≥ 6.5% A1C. Chi-squared test was used to assess differences between methods. Precision was performed on the POC systems using 10 replicates at approx. 4.5, 7, and 10% A1C. Results: Average paired biases were identical for the POC and CL analyzers (-0.04% A1C). Slopes were 0.97, 0.99, and 0.97 for the A1CNow+, DCA, and CL analyzers (p = 0.71) and intercepts were 0.15, 0.04, and 0.12 (p = 0.99). Regression values were 0.987, 0.996, and 0.998, respectively. Clinical risk agreement was 94% for A1CNow+, 100% for the DCA, and 98% for CL analyzers (p = 0.17). Pooled precision was 3.3% CV for A1CNow+ and 1.7% CV for DCA. Conclusion: The A1CNow+ and DCA were shown to be as accurate as the clinical lab in measuring A1C values. Risk analysis showed no statistical differences between the CL and POC analyzers in classifying diabetes. The A1CNow+ and DCA are valuable tools in evaluating the diabetic state and provide physicians with real-time information to better care for patients. Disclosure C.J. Szablowski: Employee; Self; PTS Diagnostics. E. Suscha: Employee; Self; PTS Diagnostics. K. Davis: Employee; Self; PTS Diagnostics. C.Z. Xie: Employee; Self; PTS Diagnostics. K. Moskowitz: Employee; Self; PTS Diagnostics. Stock/Shareholder; Self; PTS Diagnostics. J.H. Anderson: Employee; Self; PTS Diagnostics. Board Member; Self; GENEREX Biotechnology. A. Mechley: Consultant; Self; PTS Diagnostics.

Evaluation of Four HbA1c Point-of-Care Devices Using International Quality Targets: Are They Fit for the Purpose?

Point-of-care (POC) testing is becoming increasingly valuable in health care delivery, and it is important that the devices used meet the same quality criteria as main laboratory analyzers. While external quality assessment (EQA) provides a great tool for assessing quality, many POC devices are not enrolled in these schemes and standard laboratory evaluations are needed to assess performance. The Clinical and Laboratory Standards Institute (CLSI) protocols EP-5 and EP-9 were applied to investigate imprecision, accuracy and bias. We assessed bias using the mean of 4 certified secondary reference measurement procedures (SRMPs). The Afinion2™ and the Quo-Lab had CVs of ≤1.7 and ≤2.4% respectively in IFCC SI units (≤1.2 and ≤1.7% NGSP) and a bias ≤2 mmol/mol (≤0.2% NGSP) at 48 and 75 mmol/mol (6.5 and 9.0% NGSP). Sigma for the Afinion2 was 5.8 and for the Quo-Lab 4.0. Both methods passed the NGSP criteria with 2 instruments when compared with 4 individual SRMPs. The HbA1c 501 had a CV of 3.4% and 2.7% in IFCC SI units (2.1% and 1.7% NGSP) and a bias ≤2.4 mmol/mol (≤0.2% NGSP) and passed the NGSP criteria with 2 instruments compared with 4 individual SRMPs except for instrument 2 compared with the Tosoh G8. Sigma was 2.1. The A1Care had a sigma of 1.4 and failed all criteria mainly due to a high CV (6.2% and 4.1% in IFCC SI units [4.1% and 2.9% NGSP] at 48 and 75 mmol/mol [6.5 and 9.0% NGSP]). The analytical performance was excellent for the Afinion2 and the Quo-Lab, acceptable for the HbA1c 501 and unacceptable for the A1Care according to different used criteria, demonstrating that whilst performance is improving there are still areas for considerable improvement.

Hemoglobin S monitoring on TOSOH G8 in hemoglobin A1c mode in case of urgent red blood cell exchange.

Pre- and post-transfusion hemoglobin S (HbS) levels are used to document the efficacy of red blood cell exchange (RCE) in patients with sickle cell disease (SCD). In case of urgent RCE a 24/7 short turn-around time (STAT) analysis, with the ability to identify and quantify HbS, is warranted. The use of TOSOH G8 (Tosoh Europe) is evaluated for this purpose, using the variant HbA1c mode. Analytical performance of the HbS analysis on TOSOH G8 in variant HbA1c mode was evaluated, including assessment of imprecision and linearity for HbS. In addition, a comparison study between TOSOH G8 and Minicap Flex Piercing (FP) system CZE (Sebia) using 32 HbS samples (HbS range: 9%-93%) was carried out to evaluate analytical and clinical concordance. Total HbS imprecision was 1.77% and 0.31% for a sickle cell trait and a sickle cell anemia sample, respectively. An acceptable linearity (HbS range: 6%-88%) was observed (R2 >.99). Passing-Bablok regression analysis showed a significant proportional bias; however, a good analytical concordance (r>.95) was found. Our results suggested that TOSOH G8 underestimated HbS results compared with those of Minicap FP system (mean difference: -3.54%), especially in samples with a high HbS concentration. Hemoglobin S results obtained with TOSOH G8 in variant HbA1c mode are clinically acceptable to monitor urgent RCE. The observed underestimation will not alter clinical decision-making.

Interference of Thalassemias on Hemoglobin A1c Measurement by Ion-Exchange High-Performance Liquid Chromatography Method Tosoh HLC-723 G8

The presence of hemoglobinopathies could interfere with some assays for Hemoglobin A1c (HbA1c) measurement; therefore, the effect of thalassemia on ion-exchange high-performance liquid chromatography (IEHPLC) method Tosoh HLC-723 G8 (Tosoh G8) was evaluated. A total of 43 normal controls and 101 thalassemia patients were quantified by Premier Hb9210 and Tosoh G8 (variant-mode) systems. At the same time, 7 normal controls and 8 thalassemia patients were confirmed by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference method for verification. For normal controls, the HbA1c values of Tosoh G8 system (y) showed great correlation and agreement with those from Premier Hb9210 (x) (y = 0.9688x + 0.2151, r = 0.9951; mean difference 0.02 ± 0.30%), and no significant relative bias above 7% was observed; the HbA1c values obtained by Tosoh G8 were consistent with the IFCC targets (relative bias < ± 6%) in all of the samples. However, for thalassemia, the correlation between Tosoh G8 (y) and Premier Hb9210 (x) became relatively low (y = 0.8079x + 1.2897, r = 0.7780); the HbA1c values of 91.1% of the samples (92/101) obtained by Tosoh G8 were higher than those by Premier Hb9210 (mean difference 0.33 ± 0.48%) and a significant positive bias above 7% was noticed in 43.3% (45/101) thalassemia patients; when compared with the IFCC targets, the 87.5% (7/8) relative bias was > ± 6%. Thalassemia could directly affect the measurement of HbA1c using the IE-HPLC method Tosoh G8 and the clinical laboratorial staff should pay close attention.

Biological variation components of glycated hemoglobin HbA1c on tosoh G7 HPLC

Biological variation components of glycated hemoglobin HbA1c on tosoh G7 HPLC

A cost effective method for stabilizing commercial QC for the measurement of HbA1c using TOSOH G8 analyser

Haemoglobin A1c(HbA1c) represents a key biomarker in diabetes diagnosis and management, as it is indicative of glucose control during the preceding 2-3 months. Laboratories undertaking the measurement of HbA1c utilize Quality Controls (QC) to monitor precision, accuracy and reproducibility of results generated which is an integral part of any health care laboratory. Commercial companies supply lyophilised QC materials with Target mean and acceptable range. After reconstitution it is stable for 7 days as per the control inserts. The stability of reconstituted lyophilised QC material beyond 7 days is not well established and there are lacunae in the literature about the stability of reconstituted QC material at temperatures below 0C. The purpose of this study was to develop a simple method to extend the stability of are constituted commercial HbA1c lyophilised QC material in an attempt to maximize its usage, reduce wastage and make significant cost savings. Clinical laboratories could easily adopt this proposed method as it is easy to implement, and would extend the stability of their reconstituted lyophilised Quality Control (QC) material for a much longer period.

Response to Comment on Lewis et al. Management of Hemoglobin Variants Detected Incidentally in HbA1c Testing: A Common Problem Currently Lacking a Standard Approach. Diabetes Care 2017;40:e8–e9

We thank Drs. Little and Rohlfing for their comments (1) regarding our article on the management of incidental detection of hemoglobin (Hb) variants in HbA1c testing (2). We agree that awareness of the potential for interference to affect HbA1c results is essential in research and clinical care. Multiple studies (including that of Lin et al. [3]) prior to the 2016 article by Rohlfing et al. (4) had yielded no evidence of clinically significant bias resulting from HbAS or HbAC variants in Tosoh G8 results. In the Vitamin D and Type 2 Diabetes (D2d) Study, we excluded potential participants with HbAE and HbAD because clinically significant bias had been demonstrated. In a recent article by Rohlfing et al. (4), HbA1c testing using a Tosoh G8 with software version 5.20 was found to show …

HbA1c analysis by capillary electrophoresis – comparison with chromatography and an immunological method

Background: Haemoglobin A1c (HbA1c) has become an even more important analyte for clinical laboratories during recent years with the introduction of its diagnostic use for diabetes mellitus. Several different analytical principles can be used, each with their advantages and disadvantages.Aim: We wanted to compare Sebia Capillarys 2 Flex Piercing (Capillarys) with our routine HbA1c methods, which were an HPLC method (Tosoh G7) and an immunoassay (Tina-Quant on Roche Modular P) by analysing a large clinical material. Furthermore, we investigated sample stability.Methods: HbA1c analysis was performed in parallel by all three methods for more than 600 patient samples including common and some rare haemoglobin variants, as well as for several controls, some with set target values. Sample stability at room temperature and refrigerated was assessed for up to seven days.Results: Capillarys produced generally somewhat lower HbA1c values than both comparison methods, apparently due to positive bias for the comparison methods. Leaving out samples with haemoglobin variants, we found a mean bias (95% CI) for Capillarys compared to Tosoh G7 (without factorization) and Modular of −0.39 (−0.40 to −0.38) and −0.16 (−0.17 to −0.14) % HbA1c, respectively. HbA1c results were similar between instruments for samples from dialysis patients and for samples with heterozygous common haemoglobin variants, except that Tosoh G7 reported too low results in the presence of Hb E. For heterozygous Hb Raleigh, Capillarys and the immunoassay gave similar results.Conclusion: Capillarys is a convenient instrument for routine HbA1c analysis.

Evaluation of a new hemoglobin A1c analyzer for point-of-care testing.

There has been an increasing desire for the use of point-of-care testing (POCT) by both primary care clinicians and patients. This study aimed to evaluate the performance of a new POCT analyzer for hemoglobin A1c (HbA1c) testing. We assessed the accuracy, precision, and linearity of the POCT HbA1c analyzer (A1C EZ 2.0) with the Tosoh G8 Analyzer as comparative instrument, following the Clinical and Laboratory Standards Institute (CLSI) protocols. We evaluated sensitivity and specificity of the A1C EZ 2.0 in the clinical diagnosis of diabetes among 842 subjects from 79 communities in Beijing, China. Using regression analysis, the slope of the A1C EZ 2.0 vs the Tosoh G8 Analyzer was 0.9938, with an intercept of 0.0964 and a concordance correlation coefficient of 0.978. For precision, the reproducibility of CV (CVT ) were 3.7% and 2.7% at a lower (36mmol/mol (5.4%)) and higher (107mmol/mol (11.9%)) level of HbA1c respectively. The area under the receiver operating characteristic (ROC) curve for clinical diagnosis of diabetes was 0.911 with the HbA1c cut-off value of 44mmol/mol (6.14%). At the HbA1c level of 48mmol/mol (6.5%), the sensitivity and specificity were76.1% and 86.6%. The A1C EZ 2.0 has a high accuracy and precision, with a wide range of linearity, compared to a comparative laboratory instrument. It met analytical quality specifications and could be suitable for the clinical management of diabetes mellitus.

Hb variants in Korea: effect on HbA1c using five routine methods.

Quantification of glycated hemoglobin (HbA1c) is a challenge in patients with hemoglobin (Hb) variants. We evaluated the impact of various Hb variants on five routine HbA1c assays by comparing with the IFCC reference measurement procedure (RMP). Whole blood samples showing warning flags or no results on routine HPLC HbA1c assays were confirmed for Hb variants and were submitted to HbA1c quantification using Sebia Capillarys 2 Flex Piercing, Roche Tina-quant HbA1c Gen. 2, Bio-Rad Variant II Turbo 2.0, ADAMS HA-8180, Tosoh G8 standard mode, and IFCC RMP using LC-MS. Among 114 samples, the most common variants were Hb G-Coushatta (n=47), Queens (n=41), Ube-4 (n=11), Chad (n=4), Yamagata (n=4), G-His-Tsou (n=2), G-Taipei (n=1), Fort de France (n=1), Hoshida (n=1), and two novel variants (Hb α-globin, HBA 52 Gly>Cys and Hb β-globin, HBB 146 His>Asn). In terms of control samples, all the result of HbA1c were "acceptable", within the criteria of ±7% compared to IFCC RMP target values. However, percentage of "unacceptable" results of samples with Hb variants were 16% for Capillarys 2, 7% for Tina-quant, 51% for Variant II Turbo 2.0, 95% for G8 standard mode, and 89% for HA-8180. The Capillarys 2 and HA-8180 assay did not provide the results in 5 and 40 samples with Hb variants, respectively. HbA1c results from five routine assays in patients with relatively common Hb variants in Korea showed various degrees of bias compared to those of IFCC RMP. Therefore, laboratories should be aware of the limitation of their methods with respect to interference from Hb variants found commonly in their local population and suggest an alternative HbA1c quantification method.

Can the Afinion HbA1c Point-of-Care instrument be an alternative method for the Tosoh G8 in the case of Hb-Tacoma?

ABSTRACTBackground: Hb-variant interference when reporting HbA1c has been an ongoing challenge since HbA1c was introduced to monitor patients with diabetes mellitus. Most Hb-variants show an abnormal chromatogram when cation-exchange HPLC is used for the determination of HbA1c. Unfortunately, the Tosoh G8 generates what appears to be normal chromatogram in the presence of Hb-Tacoma, yielding a falsely high HbA1c value. The primary aim of the study was to investigate if the Afinion HbA1c point-of-care (POC) instrument could be used as an alternative method for the Tosoh G8 when testing for HbA1c in the presence of Hb-Tacoma.Methods: Whole blood samples were collected in K2EDTA tubes from individuals homozygous for HbA (n = 40) and heterozygous for Hb-Tacoma (n = 20). Samples were then immediately analyzed with the Afinion POC instrument. After analysis, aliquots of each sample were frozen at −80 °C. The frozen samples were shipped on dry ice to the European Reference Laboratory for Glycohemoglobin (ERL) and analyzed with three International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and National Glycohemoglobin Standardization Program (NGSP) Secondary Reference Measurement Procedures (SRMPs). The Premier Hb9210 was used as the reference method.Results: When compared to the reference method, samples with Hb-Tacoma yielded mean relative differences of 31.8% on the Tosoh G8, 21.5% on the Roche Tina-quant Gen. 2 and 16.8% on the Afinion. Conclusions: The Afinion cannot be used as an alternative method for the Tosoh G8 when testing for HbA1c in the presence of Hb-Tacoma.

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

ObjectivesTo evaluate the Bio-Rad D-100®, an HPLC analyzer for glycated hemoglobin (HbA1c) determination, and to compare its performance with the Menarini HA-8180V® and Sysmex G8®. MethodsMethod 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. ResultsMethod 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%HbA1c (−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%HbA1c (−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%HbA1c. Carry-over: 0.0024%. ConclusionsThe 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.

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.

Effects of hemoglobin C, D, E and S traits on measurements of hemoglobin A1c by twelve methods

BackgroundHemoglobin C, D Punjab, E or S trait can interfere with hemoglobin A1c (HbA1c) results. We assessed whether they affect results obtained with 12 current assay methods. MethodsHemoglobin AA (HbAA), HbAC, HbAD Punjab, HbAE and HbAS samples were analyzed on one enzymatic, nine ion-exchange HPLC and two Capillary Electrophoresis methods. Trinity ultra2 boronate affinity HPLC was the comparative method. An overall test of coincidence of least-squared linear regression lines was performed to determine if HbA1c results were statistically significantly different from those of HbAA samples. Clinically significant interference was defined as >7% difference from HbAA at 6 or 9% HbA1c compared to ultra2 using Deming regression. ResultsAll methods showed statistically significant effects for one or more variants. Clinically significant effects were observed for the Tosoh G8 variant mode and GX (all variants), GX V1.22 (all but HbAE) and G11 variant mode (HbAC). All other methods (Abbott Architect c Enzymatic, Bio-Rad D-100, Variant II NU and Variant II Turbo 2.0, Menarini HA-8180T thalassemia mode and HA-8180V variant mode, Sebia Capillarys 2 and Capillarys 3) showed no clinically significant differences. ConclusionsSeveral methods showed clinically significant interference with HbA1c results from one or more variants which could adversely affect patient care.

A Simple and Easy Process for the Determination of Estimated Plasma Glucose Level in Patients Presenting to Hospital: An Example of Multicentric Data Mining.

The aim of the present study was to determine the relation between the simultaneous fasting plasma glucose level and HbA1c in a large population of patients presenting to the hospital, based on various measurement methods available for HbA1c. HbA1c levels of 162,210 patients presenting to various hospitals and laboratories were measured based on seven different systems, and at the same time, eAG levels were calculated based on HbA1c levels. The correlation coefficients (r) between serum plasma glucose and HbA1c levels were found to be 0.809, 0.774, 0.779, 0.817, 0.704, 0.796, and 0.747 in Bio-Rad Variant II, Tosoh G8, ADAMS A1c, Trinity Boronate Affinity, Chromsystems HPLC, Roche Tina-quant, and Abbott Architect, respectively. The concordance correlation coefficients between the eAG levels as calculated with the formulas provided in the text and the eAG levels as calculated according to NGSP directions (where eAG = (28.7*HbA1c) - 46.7) were found to be between 0.9339 and 0.9866. Despite the progress made for the standardization of HbA1c measurements, the relation between serum glucose and HbA1c still demonstrated certain discrepancies pertaining to the differences in measurement methodologies. As a conclusion, each laboratory could determine different eAG levels depending on the data originated by their individual analyzer.