Short-Term Thermal-Humidity Shock Affects Point-of-Care Glucose Testing: Implications for Health Professionals and Patients

The objective was to assess the effects of short-term (≤1 hour) static high temperature and humidity stresses on the performance of point-of-care (POC) glucose test strips and meters. Glucose meters are used by medical responders and patients in a variety of settings including hospitals, clinics, homes, and the field. Reagent test strips and instruments are potentially exposed to austere environmental conditions. Glucose test strips and meters were exposed to a mean relative humidity of 83.0% (SD = 8.0%) and temperature of 42°C (107.6°F, SD = 3.2) in a Tenney BTRC environmental chamber. Stressed and unstressed glucose reagent strips and meters were tested with spiked blood samples (n = 40 measurements per time point for each of 4 trials) after 15, 30, 45, and 60 minutes of exposure. Wilcoxon’s signed rank test was applied to compare measurements test strip and meter measurements to isolate and characterize the magnitude of meter versus test strip effects individually. Stressed POC meters and test strips produced elevated glucose results, with stressed meter bias as high as 20 mg/dL (17.7% error), and stressed test strip bias as high as 13 mg/dL (12.2% error). The aggregate stress effect on meter and test strips yielded a positive bias as high as 33 mg/dL (30.1% error) after 15 minutes of exposure. Short-term exposure (15 minutes) to high temperature and humidity can significantly affect the performance of POC glucose test strips and meters, with measurement biases that potentially affect clinical decision making and patient safety.     

Accuracy of Point-of-Care Blood Glucose Measurements in Critically Ill Patients in Shock

A widely used method in monitoring glycemic status of ICU patients is point-of-care (POC) monitoring devices. A possible limitation to this method is altered peripheral blood flow in patients in shock, which may result in over/underestimations of their true glycemic status. This study aims to determine the accuracy of blood glucose measurements with a POC meter compared to laboratory methods in critically ill patients in shock. POC blood glucose was measured with a glucose-1-dehydrogenase-based reflectometric meter. The reference method was venous plasma glucose measured by a clinical chemistry analyzer (glucose oxidase-based). Outcomes assessed were concordance to ISO 15197:2003 minimum accuracy criteria for glucose meters, bias in glucose measurements obtained by the 2 methods using Bland–Altman analysis, and clinical accuracy through modified error grid analysis. A total of 186 paired glucose measurements were obtained. ISO 2003 accuracy criteria were met in 95.7% and 79.8% of POC glucose values in the normotensive and hypotensive group, respectively. Mean bias for the normotensive group was –12.4 mg/dL, while mean bias in the hypotensive group was –34.9 mg/dL. POC glucose measurements within the target zone for clinical accuracy were 90.2% and 79.8% for the normotensive and hypotensive group, respectively. POC blood glucose measurements were significantly less accurate in the hypotensive subgroup of ICU patients compared to the normotensive group. We recommend a lower threshold in confirming POC blood glucose with a central laboratory method if clinically incompatible. In light of recently updated accuracy standards, we also recommend alternative methods of glucose monitoring for the ICU population as a whole regardless of blood pressure status.     

Individuals Achieve More Accurate Results with Meters That Are Codeless and Employ Dynamic Electrochemistry

Background

Studies have shown that controlling blood glucose can reduce the onset and progression of the long-term microvascular and neuropathic complications associated with the chronic course of diabetes mellitus. Improved glycemic control can be achieved by frequent testing combined with changes in medication, exercise, and diet. Technological advancements have enabled improvements in analytical accuracy of meters, and this paper explores two such parameters to which that accuracy can be attributed.

Methods

Four blood glucose monitoring systems (with or without dynamic electrochemistry algorithms, codeless or requiring coding prior to testing) were evaluated and compared with respect to their accuracy.

Results

Altogether, 108 blood glucose values were obtained for each system from 54 study participants and compared with the reference values. The analysis depicted in the International Organization for Standardization table format indicates that the devices with dynamic electrochemistry and the codeless feature had the highest proportion of acceptable results overall (System A, 101/103). Results were significant when compared at the 10% bias level with meters that were codeless and utilized static electrochemistry (p = .017) or systems that had static electrochemistry but needed coding (p = .008).

Conclusions

Analytical performance of these blood glucose meters differed significantly depending on their technologic features. Meters that utilized dynamic electrochemistry and did not require coding were more accurate than meters that used static electrochemistry or required coding.     

Impact of Glucose Meter Error on Glycemic Variability and Time in Target Range During Glycemic Control After Cardiovascular Surgery

Background:

We retrospectively studied the impact of glucose meter error on the efficacy of glycemic control after cardiovascular surgery.

Method:

Adult patients undergoing intravenous insulin glycemic control therapy after cardiovascular surgery, with 12-24 consecutive glucose meter measurements used to make insulin dosing decisions, had glucose values analyzed to determine glycemic variability by both standard deviation (SD) and continuous overall net glycemic action (CONGA), and percentage glucose values in target glucose range (110-150 mg/dL). Information was recorded for 70 patients during each of 2 periods, with different glucose meters used to measure glucose and dose insulin during each period but no other changes to the glycemic control protocol. Accuracy and precision of each meter were also compared using whole blood specimens from ICU patients.

Results:

Glucose meter 1 (GM1) had median bias of 11 mg/dL compared to a laboratory reference method, while glucose meter 2 (GM2) had a median bias of 1 mg/dL. GM1 and GM2 differed little in precision (CV = 2.0% and 2.7%, respectively). Compared to the period when GM1 was used to make insulin dosing decisions, patients whose insulin dose was managed by GM2 demonstrated reduced glycemic variability as measured by both SD (13.7 vs 21.6 mg/dL, P < .0001) and CONGA (13.5 vs 19.4 mg/dL, P < .0001) and increased percentage glucose values in target range (74.5 vs 66.7%, P = .002).

Conclusions:

Decreasing glucose meter error (bias) was associated with decreased glycemic variability and increased percentage of values in target glucose range for patients placed on intravenous insulin therapy following cardiovascular surgery.     

Estimates of total analytical error in consumer and hospital glucose meters contributed by hematocrit, maltose, and ascorbate

Background

Patients and physicians expect accurate whole blood glucose monitoring even when patients are anemic, are undergoing peritoneal dialysis, or have slightly elevated ascorbate levels. The objective of this study was to estimate analytical error in two consumer and two hospital glucose meters contributed by variations in hematocrit, maltose, ascorbate, and imprecision.

Method

The influence of hematocrit (20–60%), maltose, and ascorbate were tested alone and in combination with each glucose meter and with a reference plasma glucose method at three concentrations of glucose. Precision was determined by consecutive analysis (n = 20) at three levels of glucose. Multivariate regression analysis was used to estimate the bias associated with the interferences, alone and in combination. Total analytical error was estimated as |% bias| + 1.96 (% imprecision).

Results

Three meters demonstrated hematocrit bias that was dependent upon glucose concentration. Maltose had profound concentration-dependent positive bias on the consumer meters, and the extent of maltose bias was dependent on hematocrit. Ascorbate produced small but statistically significant biases on three meters. Coincident low hematocrit, presence of maltose, and presence of ascorbate increased the observed bias and was summarized by estimation of total analytical error. Among the four glucose meter devices assessed, estimates of total analytical error in glucose measurement ranged from 6 to 68% under the conditions tested.

Conclusions

The susceptibility of glucose meters to clinically significant analytical biases is highly device-dependent, and low hematocrit exacerbated the observed analytical error.     

A Comprehensive Evaluation of the Performance of the Test Strip Technology for OneTouch Verio Glucose Meter Systems

Abstract Background: OneTouch(?) Verio(?) test strips (LifeScan Inc., Milpitas, CA) are designed to minimize error when used in blood glucose monitoring systems. These strips have a specialized architecture and incorporate a sophisticated waveform and proprietary algorithm. Materials and Methods: Performance of OneTouch Verio test strips was assessed in the laboratory in the presence of a wide range of patient, environmental, and pharmacologic factors. A clinical evaluation was conducted in which 296 patients and healthcare professionals (HCPs) performed glucose testing using OneTouch Verio test strips and OneTouch VerioIQ meters. Results: In the laboratory study, OneTouch Verio test strip results achieved a high level of performance over a wide range of hematocrit (19-61%), temperature (5-45(°)C), humidity (10-90% relative humidity), and altitude (0-3,048?m) conditions. Performance was not affected by 22 of 23 chemical compounds. In the clinical study, 100% (31/31) of lay-user test results were within ±10?mg/dL of reference values for blood glucose <75?mg/dL. At blood glucose ≥75?mg/dL, 99.2% (243/245) were within ±15% of reference values. A feature of the VerioIQ meter, PatternAlert(?) Technology, was correctly used and positively evaluated by >98% of lay users. Conclusions: OneTouch Verio test strips are accurate and precise over a wide range of patient, environmental, and pharmacologic conditions. In addition, lay-users were able to successfully use the OneTouch VerioIQ PatternAlert Technology without HCP training.     

Accuracy of the hemocue portable glucose analyzer in a large nonhomogeneous population

Several studies have reported inconsistent results between HemoCue (HC) whole blood glucose measurements compared to plasma glucose. We selected a large patient population with diverse pathologies and healthy volunteers to evaluate HC. For this comparison, whole blood glucose concentration was measured using HC and referenced to laboratory plasma glucose. The population (n = 512) included healthy volunteers, diabetics, and patients with heart failure, liver failure, renal failure, renal and liver transplant, and other chronic diseases. Patients were on a wide variety of medications, vitamins, and food supplements. Venous blood samples were collected in tubes containing potassium oxalate and sodium fluoride. Comparison of the results was made using the method of Bland and Altman and ANOVA at three selected glucose ranges. The glucose measurement ([HC + laboratory]/2) ranges were 24-75, 76-129, and 130-404 mg/dL. A positive bias for all three glucose ranges was observed: 38 +/- 17 mg/dL for the high glucose group compared to 24 +/- 9 mg/dL and 22 +/- 10 mg/dL for the middle and low groups, respectively. In the high glucose group 90% of the values were within 10% (R = 0.97) of the laboratory reference values compared to 81% and 55% in the normal and low glucose groups, respectively. HC glucose measurements were generally within two SD from the laboratory plasma reference. HC consistently yielded lower whole blood glucose measurements than plasma with the largest differences seen in the low glucose range (29%). HC measured more consistently at the higher glucose concentrations and was 16% lower than plasma, although the mean absolute error was highest for that range. No significant effects in the bias could be attributed to disease while possible effects from instrument modifications by the manufacturer remain uncertain.     

Performance and System Validation of a New Cellular-Enabled Blood Glucose Monitoring System Using a New Standard Reference Measurement Procedure of Isotope Dilution UPLC-MRM Mass Spectrometry

Background:

We evaluated the accuracy, precision, and linearity of the In Touch® blood glucose monitoring system (BGMS), a new color touch screen and cellular-enabled blood glucose meter, using a new rapid, highly precise and accurate ¹³C₆ isotope-dilution liquid chromatography-mass spectrometry method (IDLC-MS).

Methods:

Blood glucose measurements from the In Touch® BGMS were referenced to a validated UPLC-MRM standard reference measurement procedure previously shown to be highly accurate and precise. Readings from the In Touch® BGMS were taken over the blood glucose range of 24-640 mg/dL using 12 concentrations of blood glucose. Ten In Touch® BGMS and 3 lots of test strips were used with 10 replicates at each concentration. A lay user study was also performed to assess the ease of use.

Results:

At blood glucose concentrations <75 mg/dL 100% of the measurements are within ±8 mg/dL from the true reference standard; at blood glucose levels >75 mg/dL 100% of the measurements are within ±15% of the true reference standard. 100% of the results are within category A of the consensus grid. Within-run precision show CV < 3.72% between 24-50 mg/dL and CV<2.22% between 500 and 600 mg/dL. The results show that the In Touch® meter exceeds the minimum criteria of both the ISO 15197:2003 and ISO 15197:2013 standards. The results from a user panel show that 100% of the respondents reported that the color touch screen, with its graphic user interface (GUI), is well labeled and easy to navigate.

Conclusions:

To our knowledge this is the first touch screen glucose meter and the first study where accuracy of a new BGMS has been measured against a true primary reference standard, namely IDLC-MS.     

Analytic Characteristics of Three Bayer Contour Blood Glucose Monitoring Systems in Neonates

Background:

Hypoglycemia in infants is common, is difficult to recognize, and may lead to permanent neurologic impairment. Low glucose concentrations and high hematocrits in newborns pose significant analytic challenges for whole blood glucose meters.

Objective/Methods:

Three Bayer glucose monitoring systems were evaluated using 211 blood samples from 162 neonates (age range 5 hours to 29 days, median age 3 days). Hematocrit and whole blood glucose were determined in heparinized whole blood, and plasma glucose was determined using the Roche Cobas® 6000. Accuracy was evaluated against plasma concentrations using ISO 15197:2013 and CLSI POCT 12-A3 criteria.

Results:

Glucose imprecision on the Cobas system was 1.8-2.6% (CV) from 26-610 mg/dL. Imprecision across all meter systems was 2.8% (CV) at 130 mg/dL. Glucose concentrations, hematocrit, and total bilirubin ranged from 20-150 mg/dL, 18 -75%, and 0.5-19.6 mg/dL, respectively. Linear regression analysis of whole blood versus plasma for the 3 combined systems yielded an average slope of 1.06 and correlation coefficient greater than 0.980. Bias between the Contour and Cobas was not significantly correlated with hematocrit. Greater than 99% of meter results were within 15 mg/dL and 20% of plasma results at glucose concentrations ≤ 75 and > 75 mg/dL, respectively. Of meter results, 97% were within 12.5 mg/dL of plasma results at concentrations ≤ 100 mg/dL, while 96% of meter results were within 12.5% of plasma at concentrations > 100 mg/dL.

Conclusions:

The Bayer CONTOUR Blood Glucose Monitoring Systems exceed ISO 15197:2013 and CLSI criteria in neonatal blood samples.     

Evaluation of Hematocrit Interference With MyStar Extra and Seven Competitive Devices

Background:

In previous studies, meters employing dynamic electrochemistry (DE), have been shown to correct for hematocrit (HCT) interference. This laboratory investigation assessed the HCT stability of MyStar Extra (Sanofi) in comparison to 7 competitive devices (Accu-Chek Aviva Nano & Accu-Chek Performa, Roche Diagnostics; Contour XT and Contour Link, Bayer; FreeStyle Freedom Lite, Abbott; MyLife Pura, Ypsomed; OneTouch Verio Pro, LifeScan).

Method:

Venous heparinized blood was freshly drawn, immediately aliquoted, and manipulated to contain 3 different blood glucose concentrations (50-80 mg/dL, 150-180 mg/dL, and 350-400 mg/dL) and 5 different HCT levels (20-25%, 30-35%, 40-45%, 50-55%, and 60-65%). After careful oxygenation to normal blood oxygen pressure, each of the 15 different samples was measured 8 times with 2 devices and 2 strip lots of each meter (32 measurements/meter/sample). YSI Stat 2300 served as laboratory reference method. Next to determination of the mean absolute relative deviation (MARD), stability to HCT influence was assumed, when less than 10% difference occurred between the highest and lowest mean glucose deviations in relation to HCT over all tested glucose ranges (HIF: hematocrit interference factor).

Results:

Four of the devices showed stable performance: Contour XT (MARD: 1.3%/HIF: 6.1%), MyStar Extra (4.7%/7.1%), OneTouch Verio Pro (4.5%/7.3%), and Contour Link (6.3%/9.3%). The 4 other meters were influenced by HCT (Accu-Chek Performa: 4.7%/20.9%, Accu-Chek Aviva Nano: 4.5%/22.4%, FreeStyle Freedom Lite: 4.8%/24.5%; MyLife Pura: 6.4%/28.7%).

Conclusions:

In this study, all meters showed a good accuracy, but only 50% of them, including MyStar Extra, were shown to reliably correct for potential hematocrit influence on the meter results.     

The SCGM1 System: subcutaneous continuous glucose monitoring based on microdialysis technique

The SCGM1 System is designed to allow continuous glucose monitoring in the subcutaneous interstitial fluid for up to 120 h. The system is based on the microdialysis technique and is composed of three components: (1) a disposable Cassette, which contains the microdialysis catheter (with the necessary tubes), an electrochemical flow-through sensor for glucose measurement, and the fluid reservoirs for both the microdialysis perfusate and a reagent solution containing glucose oxidase; (2) the Sensor Unit, which houses the Cassette and is worn by the patient using a belt pack; and (3) the Data Manager, with an integrated blood glucose meter for the calibration of the glucose signal. The Data Manager also has the option of displaying the continuous glucose signal. The Sensor Unit and Data Manager exchange glucose data and calibration data by radio transmission. In vitro precision was assessed by measurements of two standard glucose solutions (90 mg/dL, 3.4%; 360 mg/dL, 2.4%) over a time course of 4 days. The mean difference (+/- SD) between SCGM1 System devices (n = 11) and 15 glucose standard solutions with different concentrations was 1.4 +/- 3.5 mg/dL. The mean relative difference and the mean absolute relative difference ranged from - 0.6% to 3.7% and from 0.2% to 3.8%, respectively. The inherent physical lag time was 31 +/- 2 min (n = 10). The interference on the glucose signal of ascorbic acid, acetaminophen, and uric acid at the highest physiological concentrations was below 4%. The SCGM1 System showed a reliable and precise performance under in vitro conditions.     

Unrecognized hypo- and hyperglycemia in well-controlled patients with type 2 diabetes mellitus: the results of continuous glucose monitoring

The aim of this study was to determine the prevalence and extent of glycemic excursions (hypo- and hyperglycemic) in elderly patients with well-controlled type 2 diabetes using a Continuous Glucose Monitor System (CGMS) (Medtronic MiniMed). Elderly patients (>65 years old) with type 2 diabetes were recruited if their glycosylated hemoglobin (HbA1c) was <7.5% and if their oral hypoglycemic therapy included a sulfonylurea. Patients were asked to undergo two consecutive 72-h periods of continuous glucose monitoring at baseline and then again at 1 month (total 288 h). Patients were asked to record four self-monitored capillary blood glucose levels each day for calibration of the monitor and also to record meal times, exercise, and symptoms of hypoglycemia. The number of hyperglycemic (>144 mg/dL), hypoglycemic (<50 mg/dL), and borderline-hypoglycemic (50-65 mg/dL) events were determined (an event was defined as a glucose value that persisted for at least 15 min with or without symptoms). Twenty-five patients (21 men, four women) 73.9 +/- 4.4 years old with an HbA1c of 6.2 +/- 0.8% were each monitored for an average of 187.57 h. The mean glucose values were: fasting, 139 +/- 40 mg/dL; 2 h post-breakfast, 167 +/- 58 mg/dL; 2 h post-lunch, 157 +/- 53 mg/dL; and 2 h post-dinner, 149 +/- 49 mg/dL. Twenty patients (80%) experienced a total of 103 hypoglycemic events, and 14 of these patients experienced 54 events where the glucose levels were 144 mg/dL 2 h postprandial) were recorded after 57% of all meals (breakfast 60%, lunch 57.5%, dinner 55.2%). The CGMS was generally well tolerated, but 52% of patients could not be studied for the full 12 days of monitoring. Thus hypoglycemia and excessive postprandial glycemic excursions are common in well-controlled patients with type 2 diabetes treated with a sulfonylurea with or without metformin. The CGMS is a useful research and clinical tool to assess glycemia in patients with type 2 diabetes but is not tolerated by all subjects.     

Three-day continuous glucose monitoring for rapid assessment of hypoglycemic events and glycemic variability in type 1 diabetic patients

This study was to determine whether glycemic variability is related to hypoglycemic events in type 1 diabetic patients, and whether the hypoglycemic events during a short-term continuous glucose monitoring system (CGMS) period parallel those measured during a 4-week self-monitoring of blood glucose (SMBG) period. We also evaluated whether glycemic variability indexes from a short-term CGMS correlate with those from a 4-week SMBG. A total of 49 type 1 diabetic patients wore CGMS devices for 3 days. These patients also performed SMBG for 4 weeks. Several indexes from the CGMS data were compared with indexes from the SMBG data. Hypoglycemic events (glucose levels <70 mg/dL) that occurred during the 3-day CGMS and 4-week SMBG periods were evaluated and compared. Hypoglycemic events were detected in 33 patients (67%) during the 3-day CGMS period. The patients with hypoglycemic events had a significantly higher glycemic variability index divided by mean glucose of CGMS, and a higher number of hypoglycemic events during the 4-week SMBG, compared to those with non-hypoglycemic events during the 3-day CGMS period. The percentage of hypoglycemic events using the 3-day CGMS was correlated with that from the 4-week SMBG (r=0.49, P<0.05) and low blood glucose index (r=0.51, P<0.05). The glycemic variability indexes from the 4-week SMBG correlated with the glycemic variability indexes from the 3-day CGMS. The short-term CGMS appears to be clinically useful for rapidly assessing the risk of hypoglycemic events and glycemic variability.     

Impact of a Reduced Error Range of SMBG in Insulin-treated Patients in Germany

Modeling approaches demonstrate that improvement in the accuracy of blood glucose (BG) meters may lead to cost savings. An improvement of accuracy of BG meters on the basis of a reduction in error range from 20% to 5% has been reported to be associated with substantial cost savings in Germany. The aim of this study is to analyze potential cost savings related to a reduction in error range from 20% to 15% and 10% of glucose meters in Germany. The health economic analysis included the number of type 1 diabetic and the number of insulin-treated patients in Germany, the costs for glucose monitoring, a model on the effects of the improvement of accuracy on the impact of severe hypoglycemic episodes, HbA1c, and subsequently myocardial infarctions and the costs of diabetes-related complications in Germany. In the model, a reduction of 1% and 3.5% reduction in severe hypoglycemic episodes, and a 0.14% and 0.28% reduction in HbA1c was included. In type 1 diabetes the savings could be equal to a reduction in health care expenditures of more than €1.0 million (20% vs 15% error range) and €3.4 million (20% vs 10% error range). Respectively, potential savings of more than €6.0 million and €20.1 million were calculated for the group of insulin-treated patients. The model demonstrates that a reduction of error range of BG meters from 20% to 15% and 10% may translate into substantial savings for the German health care system.     

Capillary blood glucose measurements in hospital inpatients using portable glucose meters

Background: The use of portable glucose meters by nursing staff to perform bedside capillary blood glucose measurements is standard practice in the management of diabetic hospital inpatients. Few studies, however, have examined the practical limitations or the cost of this technology. Aim: To investigate the performance and cost of capillary blood glucose measurements using portable glucose meters in a hospital inpatient population being managed for diabetes mellitus. Methods: The setting was a 500 bed metropolitan University Teaching hospital, with 22 meters (Glucometer-M) in routine use by about 450 accredited nursing staff. The Glucometer-M was also compared with an operator-independent meter (Hemocue) to assess the effect of operator bias on the overall efficacy and cost of the programme. Results: Retrospective analysis of Glucometer-M reagent strips and comparison of measurements (n = 72) with the Hemocue revealed a marked operator bias which diminished accuracy and increased costs. The significant proportion of low haematocrits (< 30%) in the hospital population limited the applicability of the Glucometer-M which only operates reliably over the haematocrit range 35–50%. The excess of blood glucose measurements was highlighted by both a hospital ward audit and the frequency which exceeded that of routine electrolyte assays. Conclusions: Reliable bedside estimation of capillary blood glucose levels in hospitals requires a meter which is accurate, has negligible operator bias, is largely unaffected by haematocrit, and has insignificant risk of cross-contamination. At present only the Hemocue fulfils these specifications. Irrespective of meter choice, it is necessary to develop criteria for glucose measurements and monitor adherence. (Aust NZ J Med 1993; 23: 667–671.)     

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.     

Issues and implications in the selection of blood glucose monitoring technologies

Over the last 2 decades assay technology originating in the laboratory has been adapted for the special situation of in vitro blood glucose monitoring in the home, at work or play, or at the bedside. The availability of blood glucose monitoring devices has had a significant impact on the treatment of diabetes, especially with respect to involving the patients in their treatment. The unique requirements of this type of testing have led to novel developments in sample acquisition techniques, analyte detection, measurement techniques, and error detection. The performance of these in vitro devices in terms of accuracy and imprecision is largely dependent on factors that contribute to variation in response that are related to testing with blood samples outside of the laboratory. These factors include, for example, variations in environmental conditions, the variability of hematocrit and oxygen concentrations of the blood, and the fact that the blood is used undiluted. Therefore, the technologies used have been selected, developed, optimized, and calibrated to minimize the impact of these factors. The technologies also must be capable of providing accurate, reproducible results over the large range of clinical interest from the hypoglycemic range to glucose concentrations 10 to 15 to 20 times greater. However, when selecting a technology there are invariably some trade-offs to consider. Thus, the products must be optimized to balance performance, reliability, and cost. Examples are discussed.     

血糖仪与全自动生化仪检测末梢血和静脉血血糖的比较

目的 比较血糖仪与全自动生化仪检测末梢血和静脉血的一致性. 方法 选取2012年11～12月于我科门诊就诊的糖尿病和非糖尿病患者197例,使用3款血糖仪和日立7180全自动生化分析仪分别检测末梢血和静脉血血糖,并行线性回归分析和配对t检验. 结果 当红细胞压积（Hct）在35.1％～51.6％时,3款血糖仪与日立7180相关性顺序由高到低为罗氏Accuchek（末梢血：R2=0.968,静脉血：R2=0.966）、爱科莱GT-1920、强生One Touch.爱科莱GT-1920检测末梢血与日立7180的偏倚较小,检测静脉血的偏倚较大.罗氏Accuchek检测静脉血的均值低于日立7180.强生One Touch的偏倚约为10％. 结论3 款血糖仪与全自动生化分析仪相关性均较好,Hct可对两者的相关性造成影响.     

床旁监测血糖仪葡萄糖氧化酶法及脱氢酶法准确度评估

以生化分析仪检测为参照,比较葡萄糖氧化酶法及脱氢酶法血糖仪的准确度.检测新鲜肝素锂化静脉血临床样本.根据ISO15197,血糖仪的两种方法检测结果偏倚100%在±0.56 mmol/L内(＜4.2mmol/L),≥99.7%在±20%内(≥4.2 mmol/L);根据EF9-A2,两种方法的预期误差＜10%,略＞5%;低、高血糖症界值处(＜3.89 mmol/L或＞6.11mmol/L),两种方法的κ＞0.6.两种方法间的κ＜0.6.血糖仪葡萄糖氧化酶法、脱氢酶法准确度符合ISO15197要求,与生化分析仪检测方法的差异不影响临床应用,其结果用于低、高血糖症判读一致性好.

Abstract：

Blood samples were detected by 24 blood-glucose meters using glucose oxidase and another 18 glucose meters using glucose dehydrogenase. The plasma glucose was detected by the auto-chemistry analyzer as control. According to ISO1 5197 and EF9-A2, the bias of results from both glucose meters 100% fall in the range of ±0. 56 mmol/L( ＜4. 2 mmol/L) and ≥99. 7% in the range of ±20% ( ≥4. 2 mmol/L), predicted bias were all less than the true bias(Bc). As κ＞0. 6, the results from both glucose meters were in accordance with the results from autochemistry analyzer in judging hyperglycemia ( ＞6. 11 mmol/L) and hypoglycemia ( ＜ 3.89 mmol/L). Between the results from the two blood-glucose meters, κ＜0. 6. The accuracy of both glucose-meters are accepted for the purpose of clinical diagnosis and treatment.     

Effects of a novel short-term continuous subcutaneous insulin infusion program evaluated by continuous glucose monitoring on young adult type 1 diabetic patients in Taiwan

The aim of this study is to evaluate the effectiveness of blood sugar control by a short-course reinforcement program, consisting of using continuous subcutaneous insulin infusion (CSII) and continuous glucose monitoring (CGM) for young adult type 1 diabetic patients. Twenty-six pump-na?ve type 1 diabetic patients were successively enrolled in two years. The mean disease duration was 13 years and the mean HbA1c was 8.8 %. Initially, a 3-day course of CGM was used to evaluate the baseline glycemic status of the subjects, followed by 6-day intensive insulin adjustment by CSII therapy. Thereafter, a second course of CGM was performed to evaluate the effectiveness of our outcomes in comparison to the initial measurements. All participants received necessary education and instruction as required throughout the course of the program. The glucose variability as measured by standard deviation of plasma glucose and mean amplitude of glucose excursion decreased significantly (67.8 ± 2.7 to 52.0 ± 1.8 mg/dL and 140.4 ± 6.5 to 105.5 ± 5.3 mg/dL, p < 0.001). The hypoglycemic events noted per patient were reduced by 46.4% (p = 0.003) and occurred significantly less often during nocturnal periods (-63.2%, p = 0.002). Following the adjustment, the mean daily insulin requirement was reduced by 28.05% (from 0.82 to 0.59 IU/kg) and the new proportion of 40% as basal insulin was found. The short-term CSII program provided significant improvement in blood sugar control for type 1 diabetic patients, by reducing hypoglycemic events, glucose excursion, and insulin dosage in our examined subjects.