Performance of the CONTOUR® TS Blood Glucose Monitoring System

Background

Self-monitoring of blood glucose (SMBG) remains an important component of diabetes management, engendering a need for affordable blood glucose (BG) meters that are accurate, precise, and convenient. The CONTOUR^® TS is a BG meter that endeavors to meet this need. It uses glucose dehydrogenase/flavin dinucleotide chemistry, automatic test strip calibration, and autocompensation for hematocrit along with the ease of use that has come to be expected of a modern meter. The objective of this clinical trial was to determine whether the CONTOUR TS system met these criteria.

Methods

The system was evaluated at a single clinical site with 106 subjects with type 1 or type 2 diabetes. Blood glucose values ranged from 60 to 333 mg/dl over all subjects. Both lay users and health care professionals (HCPs) tested the meters, with test strips from three different lots. Results were compared to a reference analyzer of verified precision and accuracy. Forty-nine of the subjects also participated in a home study of the meter. Lay users learned to use the system without assistance and were surveyed on its use at the end of the study.

Results

When used with capillary blood, both subjects and HCPs obtained results that exceeded the International Organization for Standardization 15197:2003 criteria, (i.e., ≥95% of values fell within 20% or 15 mg/dl of the laboratory value for BG levels greater than or less than 75 mg/dl, respectively). Specifically, lay users achieved 97.9% and HCPs 98.6%. When used with venous blood, 99.8% of measurements were within the criteria. All measurements for both capillary and venous blood fell into zones A or B of the Parkes error grid, deemed clinically accurate. Hematocrit was found to have no influence on BG measurements. A large majority of the subjects found the system easy to learn and to use.

Conclusions

The CONTOUR TS BG meter system gave accurate and reproducible results with both capillary and venous blood; subjects learned to use the meter system by following the user guide and quick reference guide.     

A comparison of blood glucose meters in Australia

OBJECTIVE: To assess the accuracy and precision of the five currently available blood glucose meters in Australia. DESIGN AND SETTING: Control solutions from manufacturers were used to determine the precision for each meter. Glucose levels in capillary blood samples from 49 patients attending a diabetes clinic were measured with each meter and with a laboratory reference method. OUTCOME MEASURES: The coefficient of variation was calculated to determine precision. Bias, Error Grid analysis, and Bland-Altman plots were used to determine accuracy. RESULTS: The CVs of most meters were acceptable at <5%. Bias ranged from 4.0 to 15.5% with only 1 meter satisfying the American Diabetes Association recommendation of <5% bias. Error Grid analysis showed that 94-100% of readings were clinically accurate, and that none of the differences from the reference method would lead to clinical errors. Bland-Altman plots showed that for two meters the magnitude of the difference between the meter and the reference method increased with increasing glucose values, but did not change significantly with glucose level for the other 3 meters. CONCLUSIONS: Currently available blood glucose meters show acceptable precision, and any errors (with respect to a laboratory method) are highly unlikely to lead to clinical errors. However, only the CareSens meter achieved a bias of less than 5%.     

Accuracy of self-monitoring of blood glucose: impact on diabetes management decisions during pregnancy

PURPOSE: This study tested the hypothesis that the accuracy of self-monitoring of blood glucose (SMBG) values of patients with diabetes during pregnancy deviates substantially from reference values. METHODS: The patients' glucose values were measured on 6 different SMBG meters; reference values were from the HemoCue B Glucose Analyzer. Over a 5-year period, 1973 comparisons between SMBG values and reference values were recorded during clinic visits and used for this study. Data were analyzed for percent of values that varied more than +/- 10.5% and +/- 15.5% from the reference value. Out-of-range data at each variance level were analyzed to determine the impact on medical management if decisions were based solely on SMBG values. RESULTS: One third of SMBG readings deviated significantly, which could adversely affect treatment for half of these patients if diabetes management was based on SMBG values. At the 10.5% deviation level, 34% of SMBG meter readings were out of range; 54% of these would have implied erroneous treatment. At the 15.5% deviation level, 18% were out of range; 63% of these would have implied erroneous management. CONCLUSIONS: The accuracy of home meters should be verified at regular intervals, and SMBG values should not be the sole criterion for diabetes management during pregnancy.     

Identifying variables associated with inaccurate self-monitoring of blood glucose: proposed guidelines to improve accuracy

PURPOSE: This study was conducted to evaluate patients' proficiency in self-monitoring of blood glucose (SMBG). METHODS: Diabetes nurse educators in 4 suburban Minneapolis clinic sites surveyed the SMBG training/cure practices of 280 patients with type 1 and type 2 diabetes. Participant SMBG technique was measured by direct observation. Participants performed a finger puncture and used their own meters to measure the first blood sample. A second sample was measured on the HemoCue B Glucose analyzer, and a third sample was used to measure hemoglobin. The series of tests were then repeated. If either of the 2 glucose tests was more than 15% from the HemoCue value, participants were reeducated about the manufacturer's suggested procedure. RESULTS: Of the 280 participants, 19% had blood glucose test results greater than the 15% limit for meter accuracy. After reeducation, 69% of those who had initially failed achieved acceptable results. The most significant problems were lack of periodic meter technique evaluation, difficulty using wipe meters, incorrect use of control solutions, lack of hand washing even when observed, and unclean meters. CONCLUSIONS: As a result of the study, guidelines were subsequently developed to evaluate meter accuracy in an outpatient setting. Further effort is needed to establish standards for evaluating SMBG.     

Capillary and venous blood glucose measurements using a direct glucose-sensing meter.

The aim of the study was to evaluate the precision and accuracy of the ExacTech home blood glucose meter when used with either capillary or venous blood and to compare this with a reference whole blood glucose assay. Non-fasting glucose measurements were used since a validation study showed no capillary-venous differences between fasting and post-prandial states. In a cross-sectional study, blood was taken from 182 patients and measured in duplicate on three batches of strips. Altogether we analysed 1089 readings. The regression of the data from capillary blood samples (meter vs reference method) had a correlation coefficient, of 0.93, and a mean bias of 0.2 mmol l-1. The corrected 90% confidence interval was +/- 1.5 mmol l-1 overall, and +/- 0.9 mmol l-1 for readings under 7.0 mmol l-1. Regression of the data from venous blood samples (meter vs reference method) had a correlation coefficient of 0.93 and a slope of x 1.1. The corrected 90% confidence interval was +/- 1.7 mmol l-1. Thus venous blood may be used even though the meter is calibrated for capillary samples but the value must be corrected by dividing by 1.1. Error-grid analysis showed that day-to-day clinical decisions could be made on the basis of ExacTech readings, although a diagnosis of borderline diabetes may not be possible.     

Glucose Meters: A Review of Technical Challenges to Obtaining Accurate Results

Glucose meters are universally utilized in the management of hypoglycemic and hyperglycemic disorders in a variety of healthcare settings. Establishing the accuracy of glucose meters, however, is challenging. Glucose meters can only analyze whole blood, and glucose is unstable in whole blood. Technical accuracy is defined as the closeness of agreement between a test result and the true value of that analyte. Truth for glucose is analysis by isotope dilution mass spectrometry, and frozen serum standards analyzed by this method are available from the National Institute of Standards and Technology. Truth for whole blood has not been established, and cells must be separated from the whole blood matrix before analysis by a method like isotope dilution mass spectrometry. Serum cannot be analyzed by glucose meters, and isotope dilution mass spectrometry is not commonly available in most hospitals and diabetes clinics to evaluate glucose meter accuracy. Consensus standards recommend comparing whole blood analysis on a glucose meter against plasma/serum centrifuged from a capillary specimen and analyzed by a clinical laboratory comparative method. Yet capillary samples may not provide sufficient volume to test by both methods, and venous samples may be used as an alternative when differences between venous and capillary blood are considered. There are thus multiple complexities involved in defining technical accuracy and no clear consensus among standards agencies and professional societies on accuracy criteria. Clinicians, however, are more concerned with clinical agreement of the glucose meter with a serum/plasma laboratory result. Acceptance criteria for clinical agreement vary across the range of glucose concentrations and depend on how the result will be used in screening or management of the patient. A variety of factors can affect glucose meter results, including operator technique, environmental exposure, and patient factors, such as medication, oxygen therapy, anemia, hypotension, and other disease states. This article reviews the challenges involved in obtaining accurate glucose meter results.     

Effects of simulated altitude on blood glucose meter performance: implications for in-flight blood glucose monitoring

BACKGROUND: Most manufacturers of blood glucose monitoring equipment do not give advice regarding the use of their meters and strips onboard aircraft, and some airlines have blood glucose testing equipment in the aircraft cabin medical bag. Previous studies using older blood glucose meters (BGMs) have shown conflicting results on the performance of both glucose oxidase (GOX)- and glucose dehydrogenase (GDH)-based meters at high altitude. The aim of our study was to evaluate the performance of four new-generation BGMs at sea level and at a simulated altitude equivalent to that used in the cabin of commercial aircrafts. Methodology/Principal Findings: Blood glucose measurements obtained by two GDH and two GOX BGMs at sea level and simulated altitude of 8000 feet in a hypobaric chamber were compared with measurements obtained using a YSI 2300 blood glucose analyzer as a reference method. Spiked venous blood samples of three different glucose levels were used. The accuracy of each meter was determined by calculating percentage error of each meter compared with the YSI reference and was also assessed against standard International Organization for Standardization (ISO) criteria. Clinical accuracy was evaluated using the consensus error grid method. The percentage (standard deviation) error for GDH meters at sea level and altitude was 13.36% (8.83%; for meter 1) and 12.97% (8.03%; for meter 2) with p = .784, and for GOX meters was 5.88% (7.35%; for meter 3) and 7.38% (6.20%; for meter 4) with p = .187. There was variation in the number of time individual meters met the standard ISO criteria ranging from 72-100%. Results from all four meters at both sea level and simulated altitude fell within zones A and B of the consensus error grid, using YSI as the reference. CONCLUSIONS: Overall, at simulated altitude, no differences were observed between the performance of GDH and GOX meters. Overestimation of blood glucose concentration was seen among individual meters evaluated, but none of the results obtained would have resulted in dangerous failure to detect and treat blood glucose errors or in giving treatment that was actually contradictory to that required.     

Evaluation of the analytical performance of the coulometry-based Optium Omega blood glucose meter

Background

The goal of diabetes treatment is maintaining near normoglycemia based on self-monitoring of blood glucose (SMBG). In this study, an evaluation of the analytical performance of the coulometry-based Optium Omega™ glucose meter designed for SMBG has been carried out.

Methods

The assessment of precision and between-lot variability was based on glucose measurements in ethylene-diaminetetraacetic acid venous blood samples. Glucose concentrations measured in 289 fresh capillary blood samples using the Omega glucose meter and the Biosen C_line analyzer were compared.

Results

Within-run imprecision coefficient of variation for the lower and higher glucose concentrations amounted to 5.09 and 2.1%, respectively. The relative lot-dependent differences found for the lower and higher glucose concentrations were equal to 6.8 and 2.6%, respectively. The glucose meter error calculated for various concentration ranges amounted from 2.22 to 4.48%. The glucose meter error met the accuracy criteria recommended by the International Organization for Standardization and the American Diabetes Association. The Passing-Bablok agreement test and error grid analysis with 96% of results in zone A indicated good concordance of results, including glucose concentrations below 100 mg/dl.

Conclusions

The evaluated Optium Omega glucose meter fits the analytical requirements for its use in blood glucose monitoring in diabetes patients.     

A multicenter study of the accuracy of the One Touch Ultra home glucose meter in children with type 1 diabetes

Data are not readily available on the accuracy of one of the most commonly used home blood glucose meters, the One Touch Ultra (LifeScan, Milpitas, California). The purpose of this report is to provide information on the accuracy of this home glucose meter in children with type 1 diabetes. During a 24-h clinical research center stay, the accuracy of the Ultra meter was assessed in 91 children, 3-17 years old, with type 1 diabetes by comparing the Ultra glucose values with concurrent reference serum glucose values measured in a central laboratory. The Pearson correlation between the 2,068 paired Ultra and reference values was 0.97, with the median relative absolute difference being 6%. Ninety-four percent of all Ultra values (96% of venous and 84% of capillary samples) met the proposed International Organisation for Standardisation (ISO) standard for instruments used for self-monitoring of glucose when compared with venous reference values. Ninety-nine percent of values were in zones A + B of the Modified Error Grid. A high degree of accuracy was seen across the full range of glucose values. For 353 data points during an insulin-induced hypoglycemia test, the Ultra meter was found to have accuracy that was comparable to concurrently used benchmark instruments (Beckman, YSI, or i-STAT); 95% and 96% of readings from the Ultra meter and the benchmark instruments met the proposed ISO criteria, respectively. These results confirm that the One Touch Ultra meter provides accurate glucose measurements for both hypoglycemia and hyperglycemia in children with type 1 diabetes.     

拜安捷TM血糖监测仪测定末梢毛细血管血糖与全自动生化分析仪测定静脉血浆血糖的临床对比研究

目的 评价拜安捷^TM血糖监测仪的精确性及其测定毛细血管血糖（capillary blood glucose，CBG）与全自动生化分析仪测定静脉血浆血糖（venous plasma glucose，VPG）的相关性。方法 188例糖尿病或非糖尿病受试者在空腹及标准餐后30、60、120min测定VPG同时用拜安捷^TM血糖监测仪测定CBG。用10台拜安捷^TM血糖监测仪分别用三个批号的试纸对低、中、高浓度水平的核对液进行测定计算其批内差异和批间差异。结果 在空腹及进标准餐后不同时间点，CBG与VPG均有良好的相关性，r均在0．950以上。误差分析图显示98．94％的数据落在A区。在不同血糖浓度下，CBG与VPG的相对差值均在5％以下。在低浓度、正常浓度及高浓度范围内，采用不同批号试纸检测，批内差异和批间差异CV值均〈5％。结论 拜安捷^TM血糖监测仪的准确性和精确性高，在空腹和进餐后不同时间及不同血糖浓度下均能较准确地反映血糖的真实水平。     

External Quality Assessment of Blood Glucose Monitors: Quality Control of Self-Monitoring of Blood Glucose: Why and How?

The control of analytical quality of self-monitoring of blood glucose (SMBG) is recommended as a routine procedure in diabetes management. This control procedure should be easily accessible to patients, convenient, not time-consuming, and provide a reliable assessment of glucose meter performance. Optimally it should be located in the diabetes outpatient clinic. Presently there are two approaches to carrying out SMBG quality control. The first is based on the comparison of results obtained by a controlled glucose meter and use of the laboratory method or point-of-care testing device as a surrogate reference analyzer. The second one is a traditionally organized external quality assessment scheme with use of a dedicated control material, which is distributed to all participants. The recommended allowable meter error in SMBG can be realistically set at 10%.     

Analysis: New Point-of-Care Blood Glucose Monitoring System for the Hospital Demonstrates Satisfactory Analytical Accuracy Using Blood from Critically Ill Patients—An Important Step toward Improved Blood Glucose Control in the Hospital

Patients managed in the intensive care units (ICUs) and general wards of the hospital experience a high incidence of hyperglycemia, hypoglycemia, and glycemic variability, despite significant hospital resources devoted to glucose control. Optimized glucose meters and monitoring systems are required to improve the safety and efficacy of insulin delivery and glucose control in the hospital. Safe insulin dosing requires timely and accurate glucose measurements, especially during dynamic changes in nutrition, insulin sensitivity, and physiological stress. In the current issue of Journal of Diabetes Science and Technology, Mitsios and coauthors describe the analytical accuracy of the new Accu-Check^® Inform II blood glucose (BG) monitoring system commercialized by F. Hofmann-La Roche Ltd. The point-of-care glucose meter achieved the desired degree of accuracy and precision, as defined by Clinical and Laboratory Standards Institute POCT12-A3 guidelines when evaluated using venous blood from 600 critically ill patients from multiple ICUs at two medical centers. Venous whole blood samples were used to obtain glucose meter results in duplicate. The remaining blood sample was centrifuged to obtain plasma for central hospital laboratory testing using the hexokinase method within 5 min of meter testing. A total of 98.8% of the 1200 Accu-Check Inform II meter’s glucose values were within ±12.5% (±12 mg/dl) of the mean laboratory glucose value, and 99.8% were within ±20% (±20 mg/dl), thus meeting the Clinical and Laboratory Standards Institute criteria. Future studies are required to evaluate the clinical performance of the new BG monitoring system in the intended-use patient populations and critical care environments, using arterial, peripheral venous, central venous, and capillary blood samples.     

Comparison of first-generation and second-generation blood glucose meters for use in a hospital setting.

This study evaluated and compared a first- and a second-generation blood glucose meter for precision, accuracy, and user preference. Two separate capillary blood glucose fingersticks were performed on 25 outpatients and 60 inpatients with diabetes. Samples were drawn for serum glucose determinations immediately following the capillary fingersticks. Comparison of the Accu-Chek II and Satellite G meters in the outpatient setting gave results similar to the reference laboratory's. When the meters were tested on inpatients, the blood glucose results were significantly higher than those obtained from the hospital laboratory. The Accu-Chek II was more precise than the Satellite G on both normal and high blood glucose samples. Nursing staff indicated preference for the Satellite G because of its quick testing time but not for other preference factors surveyed. Both meters provided more accurate assessments of blood glucose concentration than were obtained from the serum glucose samples routinely processed by our hospital laboratory. Use of a nonfluorinated tube and delayed separation of the sample with resultant glycolysis likely account for this difference.     

Clinical Accuracy of a Continuous Glucose Monitoring System With an Advanced Algorithm

Background:

We assessed the performance of a modified Dexcom G4 Platinum system with an advanced algorithm, in comparison with frequent venous samples measured on a laboratory reference (YSI) during a clinic session and in comparison to self-monitored blood glucose (SMBG) during home use.

Methods:

Fifty-one subjects with diabetes were enrolled in a prospective multicenter study. Subjects wore 1 sensor for 7-day use and participated in one 12-hour in-clinic session on day 1, 4, or 7 to collect YSI reference venous glucose every 15 minutes and capillary SMBG test every 30 minutes. Carbohydrate consumption and insulin dosing and timing were manipulated to obtain data in low and high glucose ranges.

Results:

In comparison with the laboratory reference method (n = 2,263) the system provided a mean and median absolute relative differences (ARD) of 9.0% and 7.0%, respectively. The mean absolute difference for CGM was 6.4 mg/dL when the YSIs were within hypoglycemia ranges (≤ 70 mg/dL). The percentage in the clinically accurate Clarke error grid A zone was 92.4% and in the benign error B zone was 7.1%. Majority of the sensors (73%) had an aggregated MARD in reference to YSI ≤ 10%. The MARD of CGM-SMBG for home use was 11.3%.

Conclusions:

The study showed that the point and rate accuracy, clinical accuracy, reliability, and consistency over the duration of wear and across glycemic ranges were superior to current commercial real-time CGM systems. The performance of this CGM is reaching that of a self-monitoring blood glucose meter in real use environment.     

Evaluation of a new blood glucose monitoring system with auto-calibration for home and hospital bedside use

A new self-calibrating blood glucose monitoring system (BGMS) was evaluated in a series of clinical studies with both ambulatory subjects and with hospitalized patients. The new BGMS requires a 0.6microL sample volume, provides results in 15s, and uses a glucose dehydrogenase chemistry that is oxygen independent. In the first study, Ascensia Contour meters calibrated to whole blood were tested by health care professionals (HCP) and lay users at two clinical sites. Both HCPs and lay users obtained results that fulfilled the ISO 15197:2003 criteria that 95% of self-monitoring blood glucose (SMBG) measurements should fall within +/-20% (for blood glucose (BG) concentrations> or =4.2mmol/L or +/-0.83mmol/L for BG concentrations<4.2mmol/L) of the laboratory value. Lay users and HCPs obtained 97.2 and 96.7% of glucose results within ISO criteria, respectively. In a second study, HCPs assayed blood samples from patients at the hospital bedside using meters calibrated to give whole blood glucose and meters calibrated to give plasma glucose results. Overall, 94.7% of the measurements met the ISO 15197:2003 criteria. Most lay subjects rated the BGMS as either excellent or very good in a questionnaire, and were able to use it properly without training. These findings indicate that this new BGMS is a convenient and accurate instrument system suitable for both hospital bedside use by HCPs and for SMBG by people who routinely monitor their blood glucose.     

Evaluation of Point-of-Care Blood Glucose Measurements in Patients with Diabetic Ketoacidosis or Hyperglycemic Hyperosmolar Syndrome Admitted to a Critical Care Unit

Background

Point-of-care (POC) blood glucose (BG) measurement is currently not recommended in the treatment of patients presenting with diabetic ketoacidosis (DKA) or hyperglycemic hyperosmolar syndrome (HHS).

Methods

We prospectively evaluated and compared capillary and venous POC BG values with laboratory venous glucose in patients with DKA or HHS admitted to one critical care unit over 8 months.

Results

Venous laboratory glucose was strongly correlated with venous (r = 0.98) and capillary (r = 0.96) POC glucose values, though POC glucose values were higher than venous laboratory values (venous POC 21 ± 3 mg/dl, capillary POC 30 ± 4 mg/dl; both p < .001). Increased plasma osmolality had no effect on glucose meter error, while acidemia (pH < 7.3) was associated with greater glucose meter error (p = .04) independent of glucose levels. Comparing hypothetical insulin infusion rates based on laboratory venous glucose to actual infusion rates based on POC glucose values showed that 33/61 insulin infusion rates would have been unchanged, while 28 out of 61 rates were on average 7% ± 2% higher. There were no instances of hypoglycemia in any of the patients.

Conclusions

Overall, both venous and capillary POC BG values were safe for the purpose of titrating insulin infusions in patients with severe hyperglycemia. Acidemia, but not hyperosmolality, increased POC BG value errors.     

A Ward Comparison Between the One Touch II and Glucometer II Blood Glucose Meters

A 6–week clinical evaluation of the One Touch II blood glucose meter was performed in a medical ward specializing in diabetic patients and compared to the existing Glucometer II system. Nursing staff trained in both methods performed 267 capillary blood glucose measurements using the two meters. A reference capillary blood glucose was performed simultaneously on 129 of these occasions using a Yellow Springs Instrument analyser. The One Touch II correlated better with the reference (r = 0.97) than the Glucometer II (r = 0.86) and was equally close or closer to the Yellow Springs Instrument on 82 % of occasions. A greater proportion of samples measured by the One Touch II were within 15% of the reference value (83 % vs 66 %). There were also 17 cases where the One Touch II was able to give a measurement which was outwith the analytical range of the Glucometer II. A questionnaire revealed the nursing staff unanimously preferred using the One Touch II to their present meter. It is concluded that in a ward setting the One Touch II meter showed improved accuracy, usefulness in its wider analytical range, and a greater user preference in comparison to the Glucometer II.     

Deciding between using the first or second drop of blood for the self monitoring of blood glucose

AimsTo explore whether the first or the second drop of blood is more suitable for the self-monitoring of blood glucose (SMBG).MethodsSMBG was employed in hospitalized patients using the first and second drop of blood. Venous blood glucose was measured meanwhile. The differences in blood glucose measurements were then compared in groups with different regions of blood glucose levels.ResultsThere were 802 groups of blood glucose in 526 patients. There was no significant difference in the blood glucose levels of the first and second drop of blood and venous blood. However, after combining then dividing measurements into six groups according to blood glucose concentration, we found statistically significant differences between the blood glucose levels obtained from the first drop, second drop, and venous blood in the groups containing blood glucose values <9.9 or 20–30 mmol/L. In contrast, there were no significant differences in the 10–14.9 or 15–19.9 mmol/L groups.ConclusionsIn the clinical setting, both the first or second drop of blood can be used for performing SMBG to assess real-time venous glucose. By categorizing blood glucose into different levels more accurately, we observed that there was no significant difference between the first or second drop of blood and the venous blood glucose value when blood glucose levels were maintained between 10 and 20 mmol/L. When blood glucose levels were below 10 mmol/L, the value obtained from first drop of blood was close to that from venous blood, whereas when the blood glucose level is >20 mmol/L, the blood glucose value from the second drop of blood was more accurate.     

Effect of high altitude on blood glucose meter performance

Participation in high-altitude wilderness activities may expose persons to extreme environmental conditions, and for those with diabetes mellitus, euglycemia is important to ensure safe travel. We conducted a field assessment of the precision and accuracy of seven commonly used blood glucose meters while mountaineering on Mount Rainier, located in Washington State (elevation 14,410 ft). At various elevations each climber-subject used the randomly assigned device to measure the glucose level of capillary blood and three different concentrations of standardized control solutions, and a venous sample was also collected for later glucose analysis. Ordinary least squares regression was used to assess the effect of elevation and of other environmental potential covariates on the precision and accuracy of blood glucose meters. Elevation affects glucometer precision (p = 0.08), but becomes less significant (p = 0.21) when adjusted for temperature and relative humidity. The overall effect of elevation was to underestimate glucose levels by approximately 1-2% (unadjusted) for each 1,000 ft gain in elevation. Blood glucose meter accuracy was affected by elevation (p = 0.03), temperature (p < 0.01), and relative humidity (p = 0.04) after adjustment for the other variables. The interaction between elevation and relative humidity had a meaningful but not statistically significant effect on accuracy (p = 0.07). Thus, elevation, temperature, and relative humidity affect blood glucose meter performance, and elevated glucose levels are more greatly underestimated at higher elevations. Further research will help to identify which blood glucose meters are best suited for specific environments.     

Evaluation of the quality of blood glucose meters using the HemoCue B glucose system

Analytical evaluation three models of blood glucose meters (Glucometer IV (Bayer), Glucotrend (Roche Diagnostics) and One touch (Life Scan, Johnson & Johnson)) were compared within a central laboratory to an analyzer (Hitachi 747, Boehringer-Mannheim, Grenoble, France) and to a photometric device (HemoCue B-glucose). Each glucose meters met the criteria of within-run precision defined by the Association Fran?aise d'Etudes du Diabète et des Maladies Métaboliques (ALFEDIAM). Furthermore, HemoCue B-glucose met criteria defined by the French Society of Biological Chemistry (SFBC). In the study realized within laboratory, 28 to 66% of glucose tests realized with meters differed by more than 10% from plasma values and 43% of glucose assays realized with different meters differed by more than 10% from HemoCue B-glucose value. Within clinical departments, 46 glucose meters from 5 different models were evaluated. Answers to a questionnaire stored in HemoCue B-glucose underlined the weak development of glucose meters quality assurance. Within clinical departments, 65% of glucose values realized with meters differed by more than 10% from reference values. Development in clinical departments of glucose meters quality assurance programs can be monitored by HemoCue B-glucose, and must allowed improvement of glucose meter quality.