Venous Plasma Glucose Measurements Research Articles

Evaluating the Clinical Accuracy of a Non-invasive Single-Fasting-Calibration Glucometer in Patients with Diabetes: A Multicentre Study.

The aim of this study was to evaluate the stability and accuracy of glucose measurements determined using the metabolic heat conformation (MHC)-based non-invasive glucometer in a multicentre, self-controlled clinical trial. This device is the first to obtain a medical device registration certificate awarded by the National Medical Products Administration of China (NMPA). The multicentre clinical study was conducted at three sites and enrolled 200 subjects whose glucose was measured with a non-invasive glucometer (the Contour Plus blood glucose monitoring system) and by venous plasma glucose (VPG) measurements, in a fasted state and at 2 and 4h after meals. Based on both the non-invasive and VPG measurements, 93.9% (95% confidence interval 91.7-95.6%) of the blood glucose (BG) values fell within consensus error grid (CEG) zones A + B. The measurements obtained in a fasted state and at 2h after meals were more accurate, with 99.0% and 97.0% of the BG values, respectively, falling within zones A + B. Compared to those subjects who received insulin, the proportion of values in zones A + B and the correlation coefficients were 3.1% and 0.0596 higher, respectively. The accuracy of the non-invasive glucometer was influenced by the level of insulin resistance calculated by the homeostatic model assessment method, which had a correlation coefficient with the mean absolute relative difference of - 0.1588 (P = 0.0001). The MHC-based non-invasive glucometer assessed in the present study demonstrates generally high stability and accuracy in the glucose monitoring of people with diabetes. The calculation model needs to be further explored and optimised for patients with different diabetes subtypes, levels of insulin resistance and insulin secretion capacity. ChiCTR1900020523.

876-P: Accuracy of Continuous Glucose Monitoring Compared with Capillary Blood and Venous Plasma Glucose Measurements in Medical Intensive Care Unit Patients

Objective: To assess the accuracy of the subcutaneous continuous glucose monitoring (CGM) sensor by comparing to the capillary blood glucose (CBG) and venous plasma glucose (VPG) measurements in the medical intensive care unit (MICU) patients. Subjects and Methods: In a prospective study in patients in the MICUs, Medtronic Enlite sensor was inserted in the abdominal area. Paired sensor glucose readings with reference glucose values (CBG and VPG) were collected from MICU patients receiving intravenous insulin infusion therapy. The accuracy was assessed using the mean absolute relative difference (MARD), surveillance error grid (SEG) analysis and modified Bland-Altman plot. Results: Twelve patients completed the study (age 69.3 ± 11.6 years; BMI 21.6 ± 2.9 kg/m2; APACHE II score 21.8 ± 6.3 and duration of CGM use 108.7 ± 41.1 hours). A total of 353 paired CGM and CBG glucose readings and 125 paired CGM and VPG readings were included in the analysis. Using CBG as the reference, MARD was 7.2%. The modified Bland-Altman plot showed 95% of the limit of agreement (LoA) was -18.4% to 19.2%. The SEG analysis showed that 100% of paired glucose values were within zones A or B. No clinically significant difference in the accuracy was seen between subgroups of vasopressor use (MARD 6.1% in the vasopressor group vs. 6.8% in the non-vasopressor group, p = NS). Using VPG as the reference, the MARD was 8.8%. The modified Bland-Altman plot showed 95% LoA of - 22.6% to 28.2%. The SEG analysis showed 95.2% of glucose readings were within zones A or B. Conclusion: The accuracy of the subcutaneous CGM sensor in MICU patients was comparable to that observed in non-critical care settings, with no device-related adverse events. The sensor accuracy remained within the similar range when using VPG as the references compared to using CBG as the references. No differences in terms of accuracy between the vasopressor and non-vasopressor groups were found in this study. Disclosure N. Laichuthai: None. P. Buranasupkajorn: None. W. Khovidhunkit: Speaker’s Bureau; Self; Amgen, AstraZeneca. Funding Quality Improvement Fund; King Chulalongkorn Memorial Hospital; Thai Red Cross Society (1-62-30101-A-11)

Current situation and prospect of clinical application of blood glucose monitoring

Blood glucose monitoring is clinically used to assess the degree of glucose metabolism disorders in diabetic patients, reflect the efficacy of the antidiabetic medications and to guide the adjustment of the hypoglycemic regimens. The technology of blood glucose monitoring is changing with each passing day, from frequently fingertip blood sampling to subcutaneous continuous blood glucose monitoring; from invasive to minimally invasive, and non-invasive development. At the same time, blood glucose monitoring information is analyzed from simple numerical values, to visual charts, to trend judgments. Unlike venous plasma glucose measurements, the results of blood glucose monitoring are always considered in terms of accuracy and precision. Newer, more accurate non-invasive blood glucose monitoring devices are looking forward to being applied soon. Key words: Blood glucose monitoring; Diabetes mellitus

Validity of over the counter finger stick glucose measurement devices in comparison with laboratory venous plasma glucose measurements on pregnant women with diabetes

Self-monitoring of fasting, pre and postprandial blood glucose (SMBG) is an integral part of diabetic care. The validity and accuracy of different glucometer types vary significantly and at present ,none of the local authorities carry out pre or post marketing evaluation of these devices in Sri Lanka. This study evaluated the accuracy and validity of 3 types of SMBG devices available over the counter, Device 1, Device 2 and Device 3 against a standard laboratory reference method. A random sample of 103 capillary and venous blood samples were analyzed from diabetic pregnant patients admitted to Teaching Hospital Peradeniya for Blood Sugar Series Testing. Haematocrit value was also obtained by microhaematocrit method. Analytical and clinical accuracy were determined. The correlation coefficiencies were 0.856, 0.880 and 0.873 for Device 1, Device 2 and Device 3, respectively. Only Device 2 met the International Standardization Organization (ISO) performance standards for glucometers for glucose values > 100 mg/dL whereas none of them met the ISO criteria for values < 100 mg/dL. In surveillance error grids, 87.8%, 93.3% and 81.6% of the data points were within non risk zone for Device 1, Device 2 and Device 3 whereas 11.1%, 4.4% and 17.2 % were within slightly lower risk hypoglycemia area. All types of glucometers were less reliable in detecting hypoglyacaemia. The over the counter SMBG monitoring systems are encountering certain problems in terms of accuracy and validity. Clinicians should exercise caution in making clinical decisions based on glucometer values for diabetic pregnant patients.

Impact of prandial status on the comparison of capillary glucose meter and venous plasma glucose measurements in healthy volunteers

There is a negative glucose gradient between the capillary and venous systems, produced by glucose uptake into peripheral tissues. This gradient is augmented by oral glucose ingestion in healthy volunteers; thus prandial status may impact on capillary glucose meter performance. Our primary aim was to investigate whether the (capillary-venous plasma) glucose difference changed in relation to prandial status, in healthy volunteers. Glucose was measured fasting and also one hour after an ad libitum breakfast, in 103 healthy volunteers. Duplicate capillary (finger stick) measurements were undertaken at both time points, using both the FreeStyle Lite and AccuChek Performa meters. Simultaneous venous (antecubital fossa) samples were centrifuged immediately after collection and plasma glucose was measured using the laboratory hexokinase method. Results were compared by Bland-Altman difference analysis. The mean (95% CI) pre- and postprandial (capillary-plasma) glucose differences (mmol/L) were calculated for each meter. For the Freestyle Lite, the preprandial difference was -0.51 (-0.58 to -0.45) and postprandial difference was 0.81 (0.69-0.94). Corresponding differences for the Performa were -0.13 (-0.20 to -0.06) and 1.19 (1.07-1.31), respectively. T-test comparison of participants' paired pre- and postprandial (capillary-plasma) glucose differences confirmed a significant meal-related change in glucose estimation for both meters (P < 0.0001). Also, both meters read highest at lower glucose concentrations. In healthy volunteers, both glucose meters showed a systematic positive bias one hour after breakfast. The significance of this finding in diabetes remains to be determined.

The Correlation and Accuracy of Glucose Levels between Interstitial Fluid and Venous Plasma by Continuous Glucose Monitoring System

BackgroundClinical experience with the continuous glucose monitoring systems (CGMS) is limited in Korea. The objective of this study is to evaluate the accuracy of the CGMS and the correlation between interstitial fluid and venous plasma glucose level in Korean healthy male subjects.MethodsThirty-two subjects were served with glucose solution contained same amount of test food's carbohydrate and test foods after separate overnight fasts. CGMS was performed over 3 days during hopitalization for each subjects. Venous plasma glucose measurements were carried out during 4 hours (0, 0.25, 0.5, 0.75, 1, 2, 4 hours) just before and after glucose solution and test food load. The performance of the CGMS was evaluated by comparing its readings to those obtained at the same time by the hexokinase method using the auto biochemistry machine (Hitachi 7600-110). Also, correlations between glucose recorded with CGMS and venous plasma glucose value were examined.ResultsCGMS slightly underestimated the glucose value as compared with the venous plasma glucose level (16.3 ± 22.2 mg/dL). Correlation between CGMS and venous plasma glucose values throughout sensor lifetime is 0.73 (regression analysis: slope = 1.08, intercept = 8.38 mg/dL). Sensor sensitivity can deteriorate over time, with correlations between venous blood glucose and CGMS values dropping from 0.77 during 1st day to 0.65 during 2nd and 3rd day.ConclusionThe accuracy of data provided by CGMS may be less than expected. CGMS sensor sensitivity is decreased with the passage of time. But, from this study, CGMS can be used for glucose variability tendency monitoring conveniently to the Korean.

Accuracy of bedside capillary blood glucose measurements in critically ill patients

To compare the accuracy of fingerstick with laboratory venous plasma glucose measurements (laboratory glucose) in medical ICU patients and to determine the factors which interfere with the accuracy of fingerstick measurements. The study included 80 consecutive patients aged 58+/-7 years, BMI 29.5+/-9.0, and APACHE II score 15+/-6 (277 simultaneous paired measurements). This prospective observational study compared fingerstick measurements to simultaneously sampled laboratory glucose once a day in patients in our medical ICU (twice daily if on an insulin infusion). Data recorded included patient demographics, admission diagnoses, APACHE II score, BMI, daily hematocrit, arterial blood gasses, chemistry results, concomitant medications (including vasopressors and corticosteroids), and upper extremity edema. Accuracy was defined as the percentage of paired values not in accord (>15 mg dl(-1)/ 0.83 mmol(-1)l(-1) difference for laboratory values <75 mg dl(-1)/4.12 mmol(-1)l(-1) and >20% difference for laboratory values >or=75 mg/dl). Outliers (blood glucose difference >100 mg dl(-1)/5.56 mmol(-1) l(-1)) were excluded from the correlation and distribution analyses. Mean fingerstick glucose was 129+/-45 mg/dl (7.2+/-2.5 mmol/l) and mean laboratory glucose 123+/-44 mg/dl (6.8+/-2.4 mmol/l). The correlation coefficient between the two values was 0.9110 (Clinical and Laboratory Standards Institute threshold 0.9751). The mean difference (bias) between the two methods was 8.6+/-18.6 mg/dl (0.48+/-1.0 mmol/l) and limits of agreement +45.8 and -28.6 mg/dl (+2.5 and -1.6 mmol/l). Fifty-three (19%) paired measurements in 22 patients were not in accord (CLSI threshold <or=5%). In 44 (83%) of these paired measurements fingerstick glucose was greater than laboratory glucose. The findings suggest that capillary blood glucose as measured by fingerstick is inaccurate in critically ill ICU patients and does not meet the CLSI standard. It is unclear whether the sampling method, device used, or both contributed to this inaccuracy. The wide limits of agreement suggest that fingerstick measurements should be used with great caution in protocols of tight glycemic control.

New “plasma referenced” POCT glucose monitoring systems—are they suitable for glucose monitoring and diagnosis of diabetes?

Background Results from portable glucose meters should be reported as plasma values as recommended by IFCC. Three new “plasma calibrated” blood glucose meters (Abbott Precision Xcceed, Bayer Ascensia Contour and Roche Accu-Chek Aviva) were compared against laboratory venous plasma glucose measurements to determine their suitability for patient monitoring and diabetes diagnosis. Methods 115 capillary blood samples were analyzed on each of the three meters and compared to venous plasma measurements on the Dade Behring RXL analyzer (Hexokinase method). Results We found a significant positive bias of all meters compared to the laboratory reference method. Deviations of more than 10% were seen in more than a third of all glucose values in all three devices. 13%, 8.7% and 10.4%, respectively, of the values from the Abbott, Bayer and Roche devices fell in zone B or C of the Parkes' error grid. Conclusions Neither glucose meter met the ADA or the NACB goals and should therefore not be used as screening tests to diagnose diabetes but are well suitable for patient monitoring.

Can capillary whole blood glucose and venous plasma glucose measurements be used interchangeably in diagnosis of diabetes mellitus?

According to new proposals from the American Diabetes Association (ADA) and WHO, venous peripheral plasma is the preferred system for measuring glucose for diagnosing diabetes mellitus. Owing to the instability of glucose in plasma after blood sampling, strict well-defined and standardized preanalytical conditions are essential to ensure that glucose concentration measured in plasma reflects real blood glucose in the patient. This is in contrast to the capillary whole blood measurements, which are easy to perform and well established. We investigated whether it is possible to perform analysis on capillary whole blood but express the results as plasma glucose values and hence obtain comparable results and the same predictive values for diagnosis in the individual patient? The conclusion of our investigations is that these two systems are not interchangeable and that conversion should not be done for diagnostic purposes where plasma determinations are recommended.