Diagnosing Diabetes Mellitus: Performance of Hemoglobin A1c Point-of-Care Instruments in General Practice Offices

Point-of-Care HbA1c in Clinical Practice: Caveats and Considerations for Optimal Use

Hemoglobin A1c (A1C) is widely used for the diagnosis and management of diabetes. Accurate measurement of A1C is necessary for optimal clinical value. Assay standardization has markedly improved the accuracy and consistency of A1C testing. Devices to measure A1C at point of care (POC) are commercially available, allowing rapid results when the patient is seen. In this review, we describe how standardization of A1C testing was achieved, leading to high-quality results in clinical laboratories. We address the use of POC A1C testing in clinical situations and summarize the advantages and disadvantages of POC A1C testing. We emphasize the importance of considering the limitations of these devices and following correct testing procedures to ensure that accurate A1C results are obtained for optimal care of patients.

Analytical performance specifications and quality assurance of point-of-care testing in primary healthcare

Point-of-care testing (POCT) is the fastest-growing segment of laboratory medicine. This review focuses on the essential aspects of setting analytical performance specifications (APS) and performing quality assurance for POCT in primary healthcare. In-vitro diagnostic medical devices for POCT are typically small and easy to operate. Users often have little to no laboratory experience and may not necessarily see the value of conducting quality assurance on their devices. Therefore, training, guidance, and motivation should be integral parts of the total quality management system, as they are vital for managing errors and ensuring reliable results. It is common to believe that the analytical quality of POCT should be comparable to that of laboratory testing, and as a result, APS should be the same. This paper challenges this concept. The APS for POCT can often be less stringent compared to those used in a central laboratory because the requester is closer to both the analytical and clinical situation. Point-of-care instruments should be selected based on clinical needs, the required analytical quality and user-friendliness in the intended usage setting.Quality assurance should include both internal quality control (IQC) and external quality assessment (EQA). It is recommended that IQC protocols should be dependent on the complexity of the POCT device. A scoring system to determine how frequent IQC should be analyzed in primary healthcare on different types of POCT devices has been suggested. The main challenge in EQA for POCT involves using suitable control materials that reflect instrument performance on patient samples. Obtaining commutable control materials for POCT is difficult since the matrix often is whole blood. An essential aspect of EQA for POCT is that feedback reports should be easily interpretable. Users should receive advice from the EQA organizer regarding the root causes of deviating results. Quality assurance for POCT is not an easy task and presents numerous challenges. However, there is evidence that quality assurance improves the quality of POCT measurements and, consequently, can enhance patient outcomes.

Compliance of the POCT method with the fully automated method for HbA1c determination

Previous research suggests that point-of-care (POCT) determination of glycated hemoglobin (HbA1c) is a diagnostic test that can be an adequate alternative to measuring HbA1c in the laboratory. The main goal of this study was to examine the analytical characteristics of the novel INCLIX POCT method for HbA1c determination in order to test its performance before introducing this method into routine use. HbA1c is measured in a duplicate in 44 EDTA blood samples parallel on INCLIX POCT device (Sugitech, Inc.) and using automated turbidimetric immunoinhibition test on Olympus AU400 (Beckman Coulter). The within run imprecision was 7.58%, between runs imprecision was 6.63% and 6.22%, and day-to-day imprecision was 8.80% and 7.51%. Total laboratory imprecision was in agreement with those stated by the manufacturer. A statistically significant Pearson correlation coefficient was calculated (r = 0.871, P < 0.01; linear R2 = 0.757). Using Deming regression analysis, the following equation was obtained: y = - 1.80 + 1.304x. Our results indicate statistically significant correlation, linear relationship, and a significant degree of compatibility between the two analyzed methods. However, the negative bias of the HbA1c values determined on the POCT analyzer compared to the Olympus AU400 was confirmed, highlighting the need to standardize the INCLIX method.

Assessment of Patient Satisfaction with On-Site Point-of-Care Hemoglobin A1c Testing: An Observational Study

INTRODUCTION

Poor glycemic control is a serious challenge in successful diabetes management. Given the low adherence and compliance with HbA1c testing frequency and the corresponding delay in the appropriate medication adjustment, point-of-care testing (POCT) for HbA1c provides an opportunity for better control of diabetes and higher patient satisfaction. The data with this regard are limited in Saudi Arabia. Therefore, we aimed to assess the level of patient satisfaction associated with the POCT service implementation for HbA1c and evaluate the differences between the number of requested and conducted HbA1c tests before and after POCT implementation and its effect on glycemic control in Saudi clinical practice.

METHODS

We conducted a single-center ambispective descriptive cohort study in Riyadh, Saudi Arabia. This study had two phases: the retrospective phase (January 2017 to December 2017) and the prospective phase (January 2018 to December 2018). Patient satisfaction was assessed using the patient satisfaction questionnaire short form (PSQ-18) and on-site HbA1c point-of-care testing (HbA1c-POCT) satisfaction questionnaire.

RESULTS

This study included 75 patients with diabetes (37% type 1, 63% type 2) with a mean age of 44.35 (± 17.97) years. The adherence to physician recommendations for HbA1c testing frequency increased from 24% to 85% (before and after POCT implementation, respectively). High levels of satisfaction across seven dimensions of PSQ-18 (77-88%) were reported towards the provided healthcare service after POCT implementation. Furthermore, a high level of agreement on the statements of the on-site HbA1c-POCT satisfaction questionnaire was also observed. Finally, the mean HbA1c level has significantly improved after POCT implementation compared to the traditional HbA1c laboratory testing before POCT implementation [8.34 ± 0.67 and 8.06 ± 0.62, respectively, p < 0.001).

CONCLUSION

HbA1c testing at POCT improved adherence to recommendations for HbA1c testing frequency for better glycemic control and higher patient satisfaction. POCT reduces turnaround time, improves glycemic control, and facilitates the decision-making process. HbA1c measurement with POC devices is recommended to be implemented in diabetes treatment centers. All of the described benefits of POCT come together to make HbA1c testing the most common procedure for diabetes management at the point of care.

Glycated Hemoglobin and Methods for Its Point of Care Testing

Glycated hemoglobin (HbA1c) is a product of the spontaneous reaction between hemoglobin and elevated glucose levels in the blood. It is included among the so-called advanced glycation end products, of which is the most important for the clinical diagnosis of diabetes mellitus, and it can serve as an alternative to glycemia measurement. Compared to the diagnosis of diabetes mellitus by glycemia, the HbA1c level is less influenced by a short-term problem with diabetes compensation. Mass spectroscopy and chromatographic techniques are among the standard methods of HbA1c level measurement. Compared to glycemia measurement, there is lack of simple methods for diabetes mellitus diagnosis by means of the HbA1c assay using a point-of-care test. This review article is focused on the surveying of facts about HbA1c and its importance in diabetes mellitus diagnosis, and surveying standard methods and new methods suitable for the HbA1c assay under point-of-care conditions. Various bioassays and biosensors are mentioned and their specifications are discussed.

Experience of point-of-care HbA1c testing in the English National Health Service Diabetes Prevention Programme: an observational study

INTRODUCTION

To report the observations of point-of-care (POC) glycated hemoglobin (HbA1c) testing in people with non-diabetic hyperglycemia (NDH; HbA1c 42-47 mmol/mol (6.0%-6.4%)), applied in community settings, within the English National Health Service Diabetes Prevention Programme (NHS DPP).

RESEARCH DESIGN AND METHODS

A service evaluation assessing prospectively collected national service-level data from the NHS DPP, using data from the first referral received in June 2016-October 2018. Individuals were referred to the NHS DPP with a laboratory-measured HbA1c in the NDH range and had a repeat HbA1c measured at first attendance of the program using one of three POC devices: DCA Vantage, Afinion or A1C Now+. Differences between the referral and POC HbA1c and the SD of the POC HbA1c were calculated. The factors associated with the difference in HbA1c and the association between POC HbA1c result and subsequent attendance of the NHS DPP were also evaluated.

RESULTS

Data from 73 703 participants demonstrated a significant mean difference between the referral and POC HbA1c of -2.48 mmol/mol (-0.23%) (t=157, p<0.001) with significant differences in the mean difference between devices (F(2, 73 700)=738, p<0.001). The SD of POC HbA1c was 4.46 mmol/mol (0.41%) with significant differences in SDs between devices (F(2, 73 700)=1542, p<0.001). Participants who were older, from more deprived areas and from Asian, black and mixed ethnic groups were associated with smaller HbA1c differences. Normoglycemic POC HbA1c versus NDH POC HbA1c values were associated with lower subsequent attendance at behavioral interventions (58% vs 67%, p<0.001).

CONCLUSION

POC HbA1c testing in community settings was associated with significantly lower HbA1c values when compared with laboratory-measured referrals. Acknowledging effects of regression to the mean, we found that these differences were also associated with POC method, location, individual patient factors and time between measurements. Compared with POC HbA1c values in the NDH range, normoglycemic POC HbA1c values were associated with lower subsequent intervention attendance.

Performance of Afinion HbA1c measurements in general practice as judged by external quality assurance data

Background It has been debated whether point-of care (POC) glycated hemoglobin (HbA1c) measurements methods can be used for diagnosing persons with diabetes mellitus. The aim of this study was to evaluate the analytical performance of the POC Afinion HbA1c system in the hands of the users, and to investigate which predictors that were associated with good participant performance. Methods External quality assurance (EQA) data from seven surveys in 2017-2018 with a total of 5809 Afinion participants from a POC total quality system in Norway were included in this study (response rate 90%). The control materials were freshly drawn pooled EDTA whole blood. Each participant was evaluated against the analytical performance specification of ±6% from the target value, while the Afinion system was evaluated against the pooled within-laboratory CV <2%, the between-laboratory CV <3.5%, and bias <0.3%HbA1c. Logistic regression analyses were used to investigate which factors were associated with good participant performance. Results The participant pass rates for each survey varied from 98.2% to 99.7%. The pooled within-laboratory CV varied from 1.3% to 1.5%, the between-laboratory CV varied from 1.5% to 2.1%, and bias varied between -0.17 and -0.01 %HbA1c in all surveys. Reagent lot was the only independent factor to predict good participant performance. Conclusions Afinion HbA1c fulfilled the analytical performance specifications and is robust in the hands of the users. It can therefore be used both in diagnosing and monitoring persons with diabetes mellitus, given that the instrument is monitored by an EQA system.

Availability and analytical quality of hemoglobin A1c point-of-care testing in general practitioners’ offices are associated with better glycemic control in type 2 diabetes

Background

It is not clear if point-of-care (POC) testing for hemoglobin A1c (HbA1c) is associated with glycemic control in type 2 diabetes.

Methods

In this cross-sectional study, we linked general practitioner (GP) data on 22,778 Norwegian type 2 diabetes patients to data from the Norwegian Organization for Quality Improvement of Laboratory Examinations. We used general and generalized linear mixed models to investigate if GP offices’ availability (yes/no) and analytical quality of HbA1c POC testing (average yearly “trueness score”, 0–4), as well as frequency of participation in HbA1c external quality assurance (EQA) surveys, were associated with patients’ HbA1c levels during 2014–2017.

Results

Twenty-eight out of 393 GP offices (7%) did not perform HbA1c POC testing. After adjusting for confounders, their patients had on average 0.15% higher HbA1c levels (95% confidence interval (0.04–0.27) (1.7 mmol/mol [0.5–2.9]). GP offices participating in one or two yearly HbA1c EQA surveys, rather than the maximum of four, had patients with on average 0.17% higher HbA1c levels (0.06, 0.28) (1.8 mmol/mol [0.6, 3.1]). For each unit increase in the GP offices’ HbA1c POC analytical trueness score, the patients’ HbA1c levels were lower by 0.04% HbA1c (−0.09, −0.001) (−0.5 mmol/mol [−1.0, −0.01]).

Conclusions

Novel use of validated patient data in combination with laboratory EQA data showed that patients consulting GPs in offices that perform HbA1c POC testing, participate in HbA1c EQA surveys, and maintain good analytical quality have lower HbA1c levels. Accurate HbA1c POC results, available during consultations, may improve diabetes care.

Analysis: Investigating the quality of POCT devices for HbA1c, what are our next steps?

There are a growing number of publications evaluating the performance of HbA1c point-of-care testing (POCT) devices when compared to routine laboratory instruments, but is this what we need from future studies? Here we describe the current understanding of the performance of POCT for HbA1c, which areas need further studies, and the key requirements for future publications based on performance evaluations of these devices. These include studies in clinical settings, performance measured against internationally standardized reference methods, and the need to evaluate new to the market devices that do not currently have a detailed performance history. In addition we highlight the need for external quality assessment schemes that are designed to support POCT in a wide range of clinical settings.

Accuracy of a Point-of-Care Hemoglobin A1c Assay

Point-of-care test (POCT) HbA1c assays provide rapidly available results for clinical decision-making. Accuracy and precision must be established. Venous blood samples from 300 patients were assayed for HbA1c by a laboratory technician ("laboratory assessment") with the POCT Alere Afinion™ assay and a laboratory (Premier Affinity^TM) assay. POCT results from 402 patients' fingerstick samples assayed by nine nontechnician staff ("clinical assessment") were compared with the laboratory assay. The laboratory assessment showed tight correlation (r² = .977, P < .001) between the assays. Mean absolute and relative differences were 0.01 percentage points and 2.1%, respectively. CVs for the POCT and laboratory assays were <2% and <1%, respectively. The clinical assessment also showed a tight correlation between the assays (r² = .978, P < .001), with mean absolute and relative differences of 0.2 percentage points and 3.41%, respectively. CV for the POCT assay was <2%. The POCT performed acceptably compared to the laboratory assay under realistic clinical conditions.

Are point-of-care measurements of glycated haemoglobin accurate in the critically ill?

INTRODUCTION

Critically ill patients with type 2 diabetes mellitus (T2DM) and chronic hyperglycaemia may benefit from a more liberal approach to glucose control than patients with previously normal glucose tolerance. It may therefore be useful to rapidly determine HbA1c concentrations. Point-of-care (POC) analysers offer rapid results but may be less accurate than laboratory analysis.

AIM(S)

The aim of this study was to determine agreement between POC and laboratory HbA1c testing in critically ill patients with T2DM.

METHODS

Critically ill patients with T2DM had concurrent laboratory, capillary-, and arterial-POC HbA1c measurements performed. Data are presented as mean (standard deviation) or median [interquartile range]. Measurement agreement was assessed by Lin's concordance correlation coefficient, Bland-Altman 95% limits of agreement, and classification by Cohen's kappa statistic.

RESULTS

HbA1c analysis was performed for 26 patients. The time to obtain a result from POC analysis took a median of 9 [7, 10] minutes. Laboratory analysis took a median of 328 [257, 522] minutes from the time of test request to the time of report. Lin's correlation coefficient showed almost perfect agreement (0.99%) for arterial- vs capillary-POC and both POC methods vs arterial laboratory analysis. Bland-Altman plots showed a mean difference of 2.0 (3.7) with 95% limits of agreement of -5.4 to 9.3 for capillary vs laboratory, 1.6 (3.4) and -5.1 to 8.4 for arterial vs laboratory, and -0.137 (2.6) and -5.2 to 4.9 for capillary vs arterial. Patient classification as having inadequately controlled diabetes (>53 mmol/mol) showed 100% agreement across all tests.

CONCLUSIONS

HbA1c values can be accurately and rapidly obtained using POC testing in the critically ill.

Assessment of Two Diabetes Point-of-care Analyzers Measuring Hemoglobin A1c in the Peruvian Amazon

Background:

With an estimated 174 million undiagnosed cases of diabetes mellitus worldwide and 80% of them occurring in low- and middle-income countries an effective point-of-care diagnostic tool is key to fighting this global epidemic. Glycated hemoglobin has become a reliable biomarker for the diagnosis and prognosis of diabetes.

Objective:

We assessed two point-of-care (POC) analyzers in multi-ethnic communities of the Amazon Rainforest in Peru where laboratory-based glycated hemoglobin (HbA1c) testing is not available.

Methods:

203 venous blood samples were tested for HbA1c by Afinion and DCA Vantage analyzers as well as a Premier Hb9210 high-performance liquid chromatography (HPLC) method as the reference standard. The coefficient of variation (CV) of each device was calculated to assess assay imprecision. Bland-Altman plots were used to assess bias. Ambient temperature, humidity, and barometric pressure were also evaluated for their effect on HbA1c results using multivariate regression.

Findings:

There was a wide range of HbA1c for participants based on the HPLC test: 4.4–9.0% (25–75 mmol/mol). The CV for the Afinion was 1.75%, and 4.01% for Vantage. The Afinion generated higher HbA1c results than the HPLC (mean difference = +0.56% [+6 mmol/mol]; p < 0.001), as did the DCA Vantage (mean difference = +0.32% [4 mmol/mol] p < 0.001). Temperature and humidity were not related to HbA1c; however, barometric pressure was associated with HPLC HbA1c results for the Afinion.

Conclusions:

Imprecision and bias were not low enough to recommend either POC analyzer for HbA1c determinations in this setting.

Assessment of Two Diabetes Point-of-care Analyzers Measuring Hemoglobin A1c in the Peruvian Amazon

BACKGROUND

With an estimated 174 million undiagnosed cases of diabetes mellitus worldwide and 80% of them occurring in low- and middle-income countries an effective point-of-care diagnostic tool is key to fighting this global epidemic. Glycated hemoglobin has become a reliable biomarker for the diagnosis and prognosis of diabetes.

OBJECTIVE

We assessed two point-of-care (POC) analyzers in multi-ethnic communities of the Amazon Rainforest in Peru where laboratory-based glycated hemoglobin (HbA1c) testing is not available.

METHODS

203 venous blood samples were tested for HbA1c by Afinion and DCA Vantage analyzers as well as a Premier Hb9210 high-performance liquid chromatography (HPLC) method as the reference standard. The coefficient of variation (CV) of each device was calculated to assess assay imprecision. Bland-Altman plots were used to assess bias. Ambient temperature, humidity, and barometric pressure were also evaluated for their effect on HbA1c results using multivariate regression.

FINDINGS

There was a wide range of HbA1c for participants based on the HPLC test: 4.4-9.0% (25-75 mmol/mol). The CV for the Afinion was 1.75%, and 4.01% for Vantage. The Afinion generated higher HbA1c results than the HPLC (mean difference = +0.56% [+6 mmol/mol]; p &lt; 0.001), as did the DCA Vantage (mean difference = +0.32% [4 mmol/mol] p &lt; 0.001). Temperature and humidity were not related to HbA1c; however, barometric pressure was associated with HPLC HbA1c results for the Afinion.

CONCLUSIONS

Imprecision and bias were not low enough to recommend either POC analyzer for HbA1c determinations in this setting.

Improving the quality of point-of-care testing

BACKGROUND

It is suggested that new models of primary care should have better access to test results through the use of point-of-care testing (POCT).

OBJECTIVE

To determine whether quality management of POCT leads to better results.

METHODS

A comprehensive search of the literature on quality management of POCT in primary care, where the impact of participation in quality management programmes had been investigated with relevant outcome measures.

RESULTS

Three databases were systematically searched using key words relevant to POCT and quality management, covering from 1945 to January 2017. Titles and abstracts were reviewed for relevance and papers selected for review and data extraction. Five observational studies were found in which the performance of POCT for specific analytes in external quality assurance (EQA) programmes was used to assess improvement over a period of time, varying from 3.5 to 15 years. The tests monitored were HbA1c, urine albumin, C-reactive protein, glucose and haemoglobin. In each case, the performance of the test against defined analytical criteria was used to judge improvement in performance. Different summary performance criteria were used, including the imprecision of results over a period of time (two studies) and meeting defined target values for bias and imprecision of measurement (three studies). Performance improved with time and was associated with regular participation in EQA schemes and with the use of internal quality control (IQC) procedures.

CONCLUSIONS

These findings indicate that adoption of quality management for POCT, including participation in IQC and EQA, with the support of laboratory medicine professionals, will improve the quality of the results 'produced'.

Quality Control of Norwegian Pharmacy HbA1c Testing: A Modest Beginning

BACKGROUND

Many pharmacy services involve laboratory testing using point-of-care (POC) instruments. Our aim was to describe the implementation of quality control of the HbA1c POC instruments and investigate the performance in internal quality control (IQC) and external quality control (EQA) for HbA1c POC instruments in Norwegian community pharmacies.

METHODS

Two project pharmacists from each of 11 pharmacies participated in a training program covering capillary blood sampling, how to use the POC HbA1c instrument (DCA Vantage) and IQC and EQA. The pharmacies were enrolled in an EQA program for HbA1c, and their performance was compared with that of general practitioners' (GP) offices.

RESULTS

Two of 89 (2.2%) IQC measurements were outside the acceptance interval. Seven out of 11 pharmacies sent in results in EQA in all the three surveys during six months. Two pharmacies did not analyze the control material in any of the surveys, one pharmacy analyzed the control material in one of the surveys, and one pharmacy analyzed two of the surveys. Of these pharmacies, 56-100% obtained "very good" evaluation for trueness and 71-100% obtained "very good" evaluation for precision. The corresponding numbers for GP offices were 75-87% for trueness and 84-94% for precision. No pharmacies obtained a "poor" evaluation.

CONCLUSIONS

Norwegian community pharmacies can perform IQC and EQA on a HbA1c POC instrument, and the performance is comparable with that of GP offices. The compliance in the EQA surveys was modest, but the duration of the study and participation in the EQA program was probably too short to implement all the new procedures for all pharmacies.

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

BACKGROUND

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.

METHODS

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).

RESULTS

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]).

CONCLUSIONS

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.

Investigation and Analysis of Hemoglobin A1c Measurement Systems' Performance for 135 Laboratories in China

Background:

Hemoglobin A1c (HbA1c) measurement is of great value for the diagnosis and monitoring of diabetes. Many manufacturers have developed various experiments to determine the HbA1c concentration. However, the longitudinal use of these tests requires strict quality management. This study aimed to analyze the quality of HbA1c measurement systems in China using six sigma techniques to help improve their performances.

Methods:

A total of 135 laboratories were involved in this investigation in 2015. Bias values and coefficients of variation were collected from an HbA1c trueness verification external quality assessment program and an internal quality control program organized by the National Center of Clinical Laboratories in China. The sigma (σ) values and the quality goal index (QGI) were used to evaluate the performances of different groups, which were divided according to principles and instruments.

Results:

The majority of participants (88, 65.2%) were scored as “improvement needed (σ < 3)”, suggesting that the laboratories needed to improve their measurement performance. Only 8.2% (11/135) of the laboratories were scored as “world class (σ ≥ 6)”. Among all the 88 laboratories whose σ values were below 3, 52 (59.1%) and 23 (26.1%) laboratories needed to improve measurement precision (QGI <8.0) and trueness (QGI >1.2), respectively; the remaining laboratories (13, 14.8%) needed to improve both measurement precision and trueness. In addition, 16.1% (5/31) and 15.0% (3/20) of the laboratories in “TOSOH” and “ARKRAY” groups, respectively, were scored as “world class”, whereas none of the laboratories in “BIO-RAD” group were scored as “world class”.

Conclusions:

This study indicated that, although participating laboratories were laboratories with better performance in China, the performances were still unsatisfactory. Actions should be taken to improve HbA1c measurement performance before we can include HbA1c assays in diabetes diagnosis in China.

Risk assessment and HbA1c measurement in Norwegian community pharmacies to identify people with undiagnosed type 2 diabetes - A feasibility study

OBJECTIVES

Determine the feasibility of using a diabetes risk assessment tool followed by HbA1c-measurement in a community-pharmacy setting in Norway.

METHODS

In this longitudinal study two pharmacists in each of three community pharmacies were trained to perform risk assessments, HbA1c-measurements and counselling. Pharmacy customers who were > 18 years old and could understand and speak Norwegian or English were recruited in the pharmacies during a two-months-period. Information about the service was presented in local newspapers, social media, leaflets and posters at the pharmacy. Customers wishing to participate contacted the pharmacy staff. Participants completed a validated diabetes risk test and a background questionnaire including a validated instrument for self-rated health. A HbA1c measurement was performed for individuals with a moderate to high risk of developing diabetes. If HbA1c ≥ 6.5% they were recommended to visit their general practitioner for follow-up. The pharmacies performed internal and external quality control of the HbA1c instrument.

RESULTS

Of the 211 included participants 97 (46%) were > 50 years old. HbA1c was measured for the 47 participants (22%) with high risk. Thirty-two (15%) had HbA1c values < 5.7%, twelve (5.4%) had values between 5.7%-6.4%, and three (1.4%) had an HbA1c ≥ 6.5%. Two participants with HbA1 ≥ 6.5% were diagnosed with diabetes by their general practitioner. The third was lost to follow-up. Results from internal and external quality control for HbA1c were within set limits.

CONCLUSION

The pharmacists were able to perform the risk assessment and measurement of HbA1c, and pharmacy customers were willing to participate. The HbA1c measurements fulfilled the requirements for analytical quality. Thus, it is feasible to implement this service in community pharmacies in Norway. In a large-scale study the inclusion criteria should be increased to 45 years in accordance with the population the risk test has been validated for.

Glycemic control and complications in patients with type 1 diabetes - a registry-based longitudinal study of adolescents and young adults

OBJECTIVE

The main aims of this study were to assess longitudinal glycemic control and the prevalence of retinopathy and nephropathy in young people (aged 14-30 yr) with type 1 diabetes in Norway.

METHOD

Data on 874 patients were obtained by linking two nationwide, population-based medical quality registries: The Norwegian Diabetes Register for Adults and The Norwegian Childhood Diabetes Registry.

RESULTS

Median age was 23 yr, median diabetes duration 9 yr and 51% were male. Median HbA_1c increased through adolescence to peak at ages of 17 yr for females and 19 yr for males, females had higher HbA_1c than males: 9.3% (78 mmol/mol) vs. 9.1% (76 mmol/mol). Subsequently, median HbA_1c declined but was still >8% (>64 mmol/mol) for patients approaching 30 yr. Half of the patients aged 14-17 yr and 40% of patients aged 18-25 yr had HbA_1c >9% (75 mmol/mol). Retinopathy was found in 16% and nephropathy in 13% of the population. Patients transferring from the pediatric department to adult care between the ages of 14 and 17 yr had higher median HbA_1c and prevalence of late complications than those transferring at ages 18-22 yr. Less than 40% of patients with albuminuria were treated with ACE inhibitors or angiotensin II receptor blocker.

CONCLUSION

Our results demonstrate that treatment of adolescents and young adults with type 1 diabetes in Norway is not optimal, especially for patients in their late teens. We suggest that pediatricians and endocrinologists should critically assess the care offered to this group and consider new approaches to help them improve glycemic control.

Improvement in the Quality of HbA1c Determination by Using Commutable Specimens With IFCC-Assigned Values

Background

To assess the usefulness of commutable secondary reference materials with International Federation of Clinical Chemistry (IFCC)-assigned values, for improving the quality of hemoglobin A1c (HbA 1c ) determination.

Methods

We recalibrated and evaluated 3 point-of-care-test (POCT) devices via 3 different method-specific central laboratory analyzers that were calibrated using commutable specimens with IFCC-assigned values. The staff members who performed POCT were also evaluated before and after training.

Results

HbA 1c levels measured with POCT devices showed significantly lesser bias after external mathematical calibration. The interlaboratory CVs for HbA 1c measurements decreased from 12% to 4% after training of POCT-device-operating personnel in the NycoCard group. The CVs in the DCA Vantage and Afinion groups also improved after training.

Conclusion

Calibration of laboratory devices by specimens with IFCC-assigned values and by external mathematical calibration could improve the accuracy of POCT HbA 1c measurements. Also, standardized training could improve precision in POCT HbA 1c measurements, especially for semiautomated HbA 1c POCT devices.

Impact of HbA1c Testing at Point of Care on Diabetes Management

Diabetes is a highly prevalent disease also implicated in the development of several other serious complications like cardiovascular or renal disease. HbA1c testing is a vital step for effective diabetes management, however, given the low compliance to testing frequency and, commonly, a subsequent delay in the corresponding treatment modification, HbA1c at the point of care (POC) offers an opportunity for improvement of diabetes care. In this review, based on data from 1999 to 2016, we summarize the evidence supporting a further implementation of HbA1c testing at POC, discuss its limitations and propose recommendations for further development.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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 (CV_T ) were 3.7% and 2.7% at a lower (36 mmol/mol (5.4%)) and higher (107 mmol/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 44 mmol/mol (6.14%). At the HbA1c level of 48 mmol/mol (6.5%), the sensitivity and specificity were76.1% and 86.6%.

CONCLUSION

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.

Beneficial effect of carvone, a dietary monoterpene ameliorates hyperglycemia by regulating the key enzymes activities of carbohydrate metabolism in streptozotocin-induced diabetic rats

Diabetes mellitus is a common metabolic/endocrine disorder characterized by inadequate control of carbohydrate metabolism and causes serious health issues. This study evaluates the effect of carvone, a novel monoterpene ketone, on carbohydrate metabolic enzymes in the liver of normal and streptozotocin (STZ)-induced diabetic rats. Diabetes was induced by a single intraperitoneal injection of STZ (40mg/kg b.w). STZ intoxication led to a significant increase in the levels of plasma glucose, glycosylated hemoglobin (HbA_1c) and decrease in the levels of insulin and hemoglobin (Hb). The activities of carbohydrate metabolic enzymes, glycogen, enzymatic antioxidants in pancreas and hepatic markers content were also altered. The daily oral administration of carvone (50mg/kg b.w) to diabetic rats for 30days resulted a significant decline in the levels of plasma glucose, HbA_1c and significant improve in the levels of Hb and insulin. The reversed activities of carbohydrate metabolic enzymes, enzymic antioxidants and hepatic marker enzymes in diabetic rats were renovated to near normal level by the administration of carvone. The obtained results were compared with glyclazide, a standard oral hypoglycemia drug. Histopathological analysis of liver and pancreas and immunohistochemistry of pancreas revealed that treatment with carvone reduced the STZ-induced damage to hepatic and β-cells of the pancreas. From our results, carvone regulates carbohydrate metabolism by ameliorating the key enzymes in the hepatic tissues of STZ-induced diabetic rats however further studies and safety studies are needed to validate the effects of carvone.

Long-Term Performance of Point-of-Care Hemoglobin A1c Assays

BACKGROUND

Point-of-care (POC) testing of HbA1c is used as a time-efficient tool to improve treatment and management planning for diabetes in the clinic setting. HbA1c values are the basis for monitoring ongoing response to treatment and to make adjustments to diabetes therapy. Yet, there is ongoing controversy as to the accuracy of POC assays. Diabetes is a lifelong disease, so comparability of results over a long period of time is needed to follow the response to treatment.

METHODS

We compared the Afinion™ automated boronate affinity assay and the DCA Vantage immunoassay-based POC techniques to the Tosoh G8 and Bio-Rad Variant II ion-exchange high-performance liquid chromatography (HPLC) central laboratory methods in a study lasting 3 years. College of American Pathology Survey results and American Proficiency testing were utilized to assess the external validity of the POC techniques.

RESULTS

Despite high correlations among the 4 techniques, there were significant and variable differences obtained over time. The Biorad values varied from 0.1 to 0.4% higher than the Afinion values. The DCA results were usually higher than the Afinion values, but fell below the Afinion results in the last 6 months of our study. Both POC techniques gave systematically lower values than the Tosoh measurements, and both the POC and the central laboratory measurements showed variable differences from the National Glycohemoglobin Standardization Program values over the duration of this study.

CONCLUSIONS

All who rely on POC methods as well as on central laboratory measurement of HbA1c must understand the potential limitations of these assays. The assessment of diabetes blood sugar control should proceed from the evaluation of HbA1c combined with review of plasma glucose and of self-monitored blood glucose values.

Evaluation of the point of care Afinion AS100 analyser in a community setting

Background

A ‘one stop shop’ model for multifactorial risk factor management in a culturally sensitive environment may improve cardiovascular disease and diabetes prevention. A full biochemical profile for cardiovascular disease risk assessment includes a lipid profile, glucose, glycated haemoglobin and urine albumin creatinine ratio measurements. This may require the use of more than one point of care testing instrument.

Methods

Individuals who attended a community cardiovascular disease risk screening or an audit programme of the diabetic care pathway in the community were sampled. Bland–Altman and Deming regression plots were used to assess agreement between methods for total cholesterol, high-density lipoprotein cholesterol, triglycerides, glycated haemoglobin and urine albumin creatinine ratio.

Results

There was good agreement between the Afinion AS100 analyser, Cholestech LDX and the laboratory methods for total cholesterol, high-density lipoprotein cholesterol and triglycerides ( n = 232). The Afinion AS100 agreed well with the laboratory method for glycated haemoglobin ( n = 255) and urine albumin creatinine ratio ( n = 176). There was statistically significant bias ( p = 0.03 to <0.0001) for several measurements. However, these were judged not to be clinically relevant. Specifically for the total cholesterol and high-density lipoprotein cholesterol values, we obtained good agreement (weighted kappa: 0.91 and 0.94 for the Afinion AS100 vs. Cholestech LDX and Afinion AS100 vs. laboratory method, respectively) for cardiovascular disease risk calculation using QRISK2.

Conclusions

Point of care testing can support a ‘one stop shop’ approach by providing rapid, reliable results. The Afinion AS100 analyser provides a multi-analyte platform and compares well with laboratory-based methods and another well-established point of care testing analyser.

A1c Gear: Laboratory quality HbA1c measurement at the point of care

INTRODUCTION

HbA1c is an important part of assessing the diabetic control and since the use of point-of-care devices for monitoring HbA1c is increasing, it is important to determine how these devices compare to the central laboratory.

METHODS

One hundred and twenty patient samples were analyzed on the Bio-Rad Variant™II and one POC analyzer (Sakae A1c Gear). Three patient sample pools containing ~5%, ~7%, and ~10% HbA1c levels were run over 20 days. Three reagent lots and three instruments were evaluated for the A1c Gear.

RESULTS

The 120 patient samples showed strong correlation (R(2)>0.989) when compared to the Variant™II with means=8.06% and 7.81%, for Variant IIand A1c Gear, respectively. Changing reagent lots or instruments had no impact for the A1c Gear. The ~5%, ~7%, and ~10% pools within-run and between-run imprecision was between 0.87-1.33% and 1.03-1.32%, and 1.41-2.35% and 1.24-1.89% with total imprecision of 1.67-2.35% and 1.61-2.31% for the A1c Gear and Variant II, respectively. The A1c Gear showed a small negative bias (0.25% HbA1c) across HbA1c measurement ranges of <11.5%. This bias was, however, acceptable and not considered to be clinically significant.

CONCLUSIONS

The A1c Gear meets the criteria of total CV <3% leading us to the conclusion that the A1c Gear can give results as precise as the laboratory at the POC.

Three of 7 hemoglobin A1c point-of-care instruments do not meet generally accepted analytical performance criteria

BACKGROUND

In 2009, we investigated the conformance of 8 hemoglobin A(1c) (Hb A(1c)) point-of-care (POC) instruments. Since then, instruments have improved and new devices are available on the market. In this second study, we evaluated the performance of DCA Vantage, Afinion, InnovaStar, Quo-Lab, Quo-Test, Cobas B101, and B-analyst Hb A(1c) POC instruments.

METHODS

Clinical and Laboratory Standards Institute protocols EP-5 and EP-9 were applied to investigate imprecision, accuracy, and bias. We assessed bias using the mean of 3 certified secondary reference measurement procedures (SRMPs). Assay conformance with the National Glycohemoglobin Standardization Program (NGSP) certification criteria was also evaluated. Interference of common Hb variants was investigated for methods that could work with hemolysed material.

RESULTS

The total CVs for all instruments, except for the DCA Vantage at a high Hb A(1c) value, were ≤3.1% in SI units and ≤2.1% in Diabetes Control and Complications Trial (DCCT) units. Afinion, DCA Vantage, B-analyst, and Cobas B101 instruments passed the NGSP criteria with 2 different reagent lot numbers. Quo-Test, Quo-Lab, and InnovaStar instruments had a negative bias compared to the mean of the 3 SRMPs and failed NGSP criteria. Most of the common Hb variants did not interfere with the investigated instruments, except Hb AE for the Cobas B101.

CONCLUSIONS

Afinion, DCA Vantage, Cobas B101, and B-analyst instruments met the generally accepted performance criteria for Hb A(1c). Quo-Test, Quo-Lab, and InnovaStar met the criteria for precision but not for bias. Proficiency testing should be mandated for users of Hb A1c POC assays to ensure quality.

[Assays of HbA1c and Amadori products in human biology]

Different Amadori products, formed during the early steps of the non-enzymatic glycation of proteins, may be assayed in current practice in human biology. The most important marker is HbA1c, resulting from the binding of glucose to the N-terminal extremity of HbA beta chains. HbA1c may be evaluated by various techniques (ion exchange or affinity high performance liquid chromatography, capillary electrophoresis, immunoassay, enzymatic technique) and is considered the best marker of diabetic patient survey. Due to its irreversible and cumulative formation, it provides a retrospective information on the glycemic balance over the four to eight weeks preceding blood collection. It benefits from an international standardization, based on a reference method using liquid chromatography coupled to capillary electrophoresis or mass spectrometry, maintained by an international network of reference laboratories. When HbA1c assay cannot be used (anemia, hemolysis, hemoglobinopathy) or when a shorter period of glycemic equilibrium must be evaluated (child and adolescent, pregnancy, therapeutic changes), other Amadori products may be assayed, like plasma fructosamine (all plasma glycated proteins) or glycated albumin. Nevertheless, these assays are less used in practice, because their semiological value has been less evidenced. Besides, fructosamine assay lacks specificity, and glycated albumin assay has been described recently. An expanding use of HbA1c assay is expected, especially for the diagnosis of diabetes mellitus and the evaluation of other risks, especially cardiovascular ones.