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.

Technical aspects of the Parkes error grid.

BACKGROUND: The Parkes error grid, which was developed in 1994, presented performance zones for blood glucose (BG) monitors with borders that were not mathematically specified at the time the grid was published. METHODS: In this article, we (1) review the history of the Parkes error grid, (2) present the never-before-published exact coordinates and specifications of the grid so that others may produce an exact replica of the original grid, and (3) discuss our suggestions how this metric should be applied. RESULTS: The new ISO15197:2013 guideline for system accuracy assessment of BG meters for patient self-measurement incorporates use of this metric for defining acceptable accuracy of BG monitors. It is expected that, for regulatory purposes, this document will stipulate that the error grid version for type 1 diabetes should be applied with the caveat that only the A zone represents acceptable accuracy. CONCLUSIONS: It remains to be seen by how much the new error grid, which is currently being developed by the Food and Drug Administration/Diabetes Technology Society/American Diabetes Association/The Endocrine Society/Association for Advancement of Medical Instrumentation, will deviate from the Parkers error grid.

Performance evaluation and labeling comprehension of a new blood glucose monitoring system with integrated information management.

BACKGROUND: This study evaluated performance and product labeling of CONTOUR® USB, a new blood glucose monitoring system (BGMS) with integrated diabetes management software and a universal serial bus (USB) port, in the hands of untrained lay users and health care professionals (HCPs). METHOD: Subjects and HCPs tested subject's finger stick capillary blood in parallel using CONTOUR USB meters; deep finger stick blood was tested on a Yellow Springs Instruments (YSI) glucose analyzer for reference. Duplicate results by both subjects and HCPs were obtained to assess system precision. System accuracy was assessed according to International Organization for Standardization (ISO) 15197:2003 guidelines [within ±15 mg/dl of mean YSI results (samples <75 mg/dl) and ±20% (samples ≥75 mg/dl)]. Clinical accuracy was determined by Parkes error grid analysis. Subject labeling comprehension was assessed by HCP ratings of subject proficiency. Key system features and ease-of-use were evaluated by subject questionnaires. RESULTS: All subjects who completed the study (N = 74) successfully performed blood glucose measurements, connected the meter to a laptop computer, and used key features of the system. The system was accurate; 98.6% (146/148) of subject results and 96.6% (143/148) of HCP results exceeded ISO 15197:2003 criteria. All subject and HCP results were clinically accurate (97.3%; zone A) or associated with benign errors (2.7%; zone B). The majority of subjects rated features of the BGMS as "very good" or "excellent." CONCLUSIONS: CONTOUR USB exceeded ISO 15197:2003 system performance criteria in the hands of untrained lay users. Subjects understood the product labeling, found the system easy to use, and successfully performed blood glucose testing.

Performance of the DIDGET blood glucose monitoring system in children, teens, and young adults.

BACKGROUND: This study evaluated the performance of the DIDGET® blood glucose monitoring system (BGMS) in the hands of its intended users: children, teens, and young adults with diabetes. METHODS: Finger stick capillary blood samples were tested in duplicate by subjects (with parent/guardian assistance, if needed) and health care professionals using the DIDGET BGMS, and results were compared with those obtained using a Yellow Springs Instruments (YSI) glucose analyzer. Modified venous blood samples (i.e., glycolyzed or spiked with glucose) were used to analyze meter performance under extreme glucose concentrations. Accuracy was assessed using International Organization for Standardization (ISO) 15197:2003 guidelines (i.e., 95% of meter results within ±15 mg/dl or ±20% of reference values). RESULTS: A total of 123 subjects aged 4 to 24 years with type 1 or type 2 diabetes were enrolled. The DIDGET meter achieved accuracy according to ISO 15197:2003 criteria: >97% of meter results were within ±15 mg/dl or ±20% of reference values. Regression analyses showed a high degree of correlation between meter and YSI results: coefficient of determination (R(2)) = 98.2% for all samples combined and 97.2% for capillary samples only. Clinical accuracy for combined samples was demonstrated by Parkes consensus error grid analyses; 100% of meter results were in zone A (98.5%) or zone B (1.5%). There was no difference in performance or accuracy across age subsets. Hematocrit values did not affect meter blood glucose results. CONCLUSION: The DIDGET BGMS provided accurate test results across all age ranges in children, teens, and young adults with diabetes.

Evaluation of a novel continuous glucose measurement device in patients with diabetes mellitus across the glycemic range.

BACKGROUND: This glucose clamp study assessed the performance of an electrochemical continuous glucose monitoring (CGM) system for monitoring levels of interstitial glucose. This novel system does not require use of a trocar or needle for sensor insertion. METHOD: Continuous glucose monitoring sensors were inserted subcutaneously into the abdominal tissue of 14 adults with type 1 or type 2 diabetes. Subjects underwent an automated glucose clamp procedure with four consecutive post-steady-state glucose plateau periods (40 min each): (a) hypoglycemic (50 mg/dl), (b) hyperglycemic (250 mg/dl), (c) second hypoglycemic (50 mg/dl), and (d) euglycemic (90 mg/dl). Plasma glucose results obtained with YSI glucose analyzers were used for sensor calibration. Accuracy was assessed retrospectively for plateau periods and transition states, when glucose levels were changing rapidly (approximately 2 mg/dl/min). RESULTS: Mean absolute percent difference (APD) was lowest during hypoglycemic plateaus (11.68%, 14.15%) and the euglycemic-to-hypoglycemic transition (14.21%). Mean APD during the hyperglycemic plateau was 17.11%; mean APDs were 18.12% and 19.25% during the hypoglycemic-to-hyperglycemic and hyperglycemic-to-hypoglycemic transitions, respectively. Parkes (consensus) error grid analysis (EGA) and rate EGA of the plateaus and transition periods, respectively, yielded 86.8% and 68.6% accurate results (zone A) and 12.1% and 20.0% benign errors (zone B). Continuous EGA yielded 88.5%, 75.4%, and 79.3% accurate results and 8.3%, 14.3%, and 2.4% benign errors for the euglycemic, hyperglycemic, and hypoglycemic transition periods, respectively. Adverse events were mild and unlikely to be device related. CONCLUSION: This novel CGM system was safe and accurate across the clinically relevant glucose range.