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.     

Integrated self-monitoring of blood glucose system: handling step analysis

Self-monitoring of blood glucose (SMBG) implicates a number of handling steps with the meter and the lancing device. Numerous user errors can occur during SMBG, and each step adds to the complexity of use. This report compares the required steps to perform SMBG of one fully integrated (the second generation of the Accu-Chek® Mobile), three partly integrated (Accu-Chek Compact Plus, Ascensia® Breeze®2, and Accu-Chek Aviva), and six conventional (Bayer Contour®, Bayer Contour USB, BGStar™, FreeStyle Lite®, OneTouch® Ultra® 2, and OneTouch Verio™Pro) systems. The results show that the fully integrated system reduces the number of steps to perform SMBG. The mean decrease is approximately 70% compared with the other systems. We assume that a reduction of handling steps also reduces the risk of potential user errors and improves the user-friendliness of the system.     

A fatal case of disseminated zygomycosis associated with the use of blood glucose self-monitoring equipment

We report a fatal case of disseminated zygomycosis due to Cunninghamella bertholletiae in a 68-year-old man with myelodysplasia and type II diabetes mellitus, receiving desferrioxamine therapy for iron overload secondary to multiple transfusions. It is thought that he acquired the infection through the use of blood glucose self-monitoring equipment.     

Performance of a New Meter Designed for Assisted Monitoring of Blood Glucose and Point-of-Care Testing

Background

Blood glucose (BG) meters used for assisted monitoring of blood glucose (AMBG) require different attributes compared with meters designed for home use. These include safety considerations (i.e., minimized risk of blood-borne pathogen transmission), capability for testing multiple blood sample types, and enhanced performance specifications. The OneTouch^® Verio™Pro+ BG meter is designed to incorporate all of these attributes.

Methods

Meter accuracy was assessed in clinical studies with arterial, venous, and capillary blood samples with a hematocrit range of 22.9–59.8%. The effect of interferents, including anticoagulants, on accuracy was evaluated. The meter disinfection protocol was validated, and instructions for use and user acceptance of the system were assessed.

Results

A total of 97% (549/566) of BG measures from all blood sample types and 95.5% (191/200) of arterial blood samples were within ±12 mg/dl or 12.5% of reference measurements. The system was unaffected by 4 anticoagulants and 57 of 59 endogenous and exogenous compounds; it was affected by 2 compounds: pralidoxime iodide and xylose. Bleach wipes were sufficient to disinfect the meter. Users felt that the meter''s quality control (QC) prompts would help them to comply with regulatory requirements.

Conclusions

The meter provided accurate measurements of different blood samples over a wide hematocrit range and was not affected by 57 physiologic and therapeutic compounds. The QC prompts and specific infection-mitigating design further aid to make this meter system practical for AMBG in care facilities.     

Practical Use of Self-Monitoring of Blood Glucose Data

Self-monitoring of blood glucose provides information about blood glucose control. The data become useful information and knowledge through careful analysis for patterns that are appropriate or can be corrected. Some analyses can be performed on newer blood glucose meters, but most often, this needs to be done on a computer, tablet, or smartphone. There are a few established methods of presenting the data that make analysis easier. In this article, we discuss four types of data presentations and the methods for utilizing them.     

Penny Wise and Pound Foolish: Will Shortsighted Cost Reduction Measures Compromise Patient Access to Promising Self-Monitoring of Blood Glucose Technology?

In this issue of Journal of Diabetes Science and Technology, Grady and coauthors enrolled 101 patients with type 1 and type 2 diabetes to evaluate new technology incorporated into the LifeScan VerioPro and VerioIQ blood glucose meters. The “pattern detection” software provides real-time, onscreen messages that alert users to patterns of high glucose (fasting and premeal) and low glucose as they are detected. The study showed that most participants possess a good understanding of the factors that can cause hyperglycemia; however, their understanding of the causes of hypoglycemia events was not as strong. Nevertheless, more than 70% of participants indicated they preferred to use a blood glucose meter that provides pattern detection capability. Although not designed to assess the impact of the pattern detection tool on clinical outcomes, the study highlights the value of continuous innovation in self-monitoring of blood glucose (SMBG) technology among manufacturers. Unfortunately, many patients may never have access to these systems due to reductions in Medicare reimbursement. Instead, they may be forced to use SMBG systems that are inaccurate and provide inadequate patient support. Stronger regulatory requirements are needed to ensure that all SMBG systems marketed to patients are accurate, reliable, and supported by adequate patient training, and current health care reimbursement policies should be restructured to encourage manufacturers to continue their efforts to develop innovative technology to further improve the utility and usability of their SMBG systems.     

Influence of Partial Pressure of Oxygen in Blood Samples on Measurement Performance in Glucose-Oxidase-Based Systems for Self-Monitoring of Blood Glucose

Background

Partial pressure of oxygen (pO₂) in blood samples can affect blood glucose (BG) measurements, particularly in systems that employ the glucose oxidase (GOx) enzyme reaction on test strips. In this study, we assessed the impact of different pO₂ values on the performance of five GOx systems and one glucose dehydrogenase (GDH) system. Two of the GOx systems are labeled by the manufacturers to be sensitive to increased blood oxygen content, while the other three GOx systems are not.

Methods

Aliquots of 20 venous samples were adjusted to the following pO₂ values: <45, ~70, and ≥150 mmHg. For each system, five consecutive measurements on each sample aliquot were performed using the same test strip lot. Relative differences between the mean BG results at pO₂ ~70 mmHg, which is considered to be similar to pO₂ in capillary blood samples, and the mean BG result at pO₂ <45 and ≥150 mmHg were calculated.

Results

For all tested GOx systems, mean relative differences in the BG measurement results were between 6.1% and 22.6% at pO₂ <45 mmHg and between -7.9% and -14.9% at pO₂ ≥150 mmHg. For both pO₂ levels, relative differences of all tested GOx systems were significant (p < .0001). The GDH system showed mean relative differences of -1.0% and -0.4% at pO₂ values <45 and ≥150 mmHg, respectively, which were not significant.

Conclusions

These data suggest that capillary blood pO₂ variations lead to clinically relevant BG measurement deviations in GOx systems, even in GOx systems that are not labeled as being oxygen sensitive.     

The Effects of Self-Regulation Strategies on Goal Attainment for Students with Developmental Disabilities in General Education Classrooms

Self-regulation and other student-directed learning strategies have the potential to benefit students with developmental disabilities and mental retardation in general education classrooms. However, to date, there is little information about use of such strategies in general education classrooms, particularly at the secondary education level. This study examined the effect of a self-regulation multicomponent process (antecedent cue regulation or self-monitoring with self-evaluation and self-reinforcement) with 3 students with developmental disabilities in typical classrooms. Use of the self-regulation strategies improved adaptive behaviors related to class participation or decreased problem behaviors for all students. Also, teachers working with students indicated that they had exceeded their expectations for achieving goals related to the target behaviors. The potential for use of self-regulation strategies to promote successful inclusion is discussed.     

The Business of Self-Monitoring of Blood Glucose: A Market Profile

The market for self-monitoring of blood glucose (SMBG) approached $8.8 billion worldwide in 2008. Yet despite dramatic double-digit growth in sales of SMBG products since 1980, the business is now facing declining prices and slower dollar growth. Given that SMBG meters and test strips are viewed by consumers and insurers as essentially generic products, it will be extremely challenging for new market entrants to displace well-entrenched existing competitors without a truly innovative technology. Also, in the face of declining glucose test strip prices, market expansion can only occur through identification of more of the undiagnosed diabetes population and convincing existing diabetes patients to adopt glucose testing or to test more frequently. Ultimately, a combination of technology innovations, patient education, and economic incentives may be needed to significantly expand the SMBG market and build sustainable long-term dollar growth for SMBG vendors.     

The Effect of Education and Self-monitoring of Blood Glucose on Glycosylated Hemoglobin in Type I Diabetes

ABSTRACT The influence on glycosylated hemoglobin (HbA₁) of formal education as compared with self-monitoring of blood glucose (SMBG) was studied in a randomized 18-month trial. All adult type I diabetics in a community were identified. Forty-one of these patients had had diabetes for 20 years or less. Thirty-seven patients were included in the study and finally randomized into four groups. Ten patients received individual formal education followed by SMBG, eight patients were instructed in SMBG without pre-education, nine patients were given only formal education and 10 patients made up a reference group. Education did not improve the mean HbA₁ values. SMBG resulted in a decrease by 2% in HbA₁ from 12 to 10% (p<0.05). The final HbA₁ level, however, did not differ significantly between any of the groups. SMBG was accepted by 80% of the patients. The liability to hypoglycemia was about equal in the four groups. It was concluded that SMBG, but not education, improved metabolic control to a certain degree.