Relationships of glucose concentrations in capillary whole blood, venous whole blood and venous plasma

Evaluation of low volume sampling devices for a pharmacodynamic biomarker analysis: Challenges and solutions

Low volume sampling technologies have gained popularity as they are minimally invasive, reduce patient burden, enhance population diversity, and have the potential to facilitate decentralized clinical trials. Herein, we validated a Gyrolab assay to measure soluble Mucosal Addressin Cell Adhesion Molecule 1 (sMAdCAM-1) in dried blood samples collected using two low volume sampling devices, Mitra and Tasso-M20. This validated assay was implemented in a proof-of-concept study to compare three low volume sampling devices (Mitra, Tasso-M20 and TassoOne Plus) with serum collected via venipuncture from healthy volunteers receiving etrolizumab. We observed significantly higher concentration of sMAdCAM-1 in dried blood samples collected using Mitra and Tasso-M20 compared to serum in some paired samples, which was attributed to interference from the dried blood extraction buffer. To mitigate this interference, samples required substantial dilution into the appropriate buffer, which negatively impacted the detectability of sMAdCAM-1 with the Gyrolab assay. By employing the Quanterix single molecule array (Simoa), known for its superior assay sensitivity, the interference was minimized in the diluted samples. Both liquid blood collected in TassoOne Plus and dried blood collected using Mitra and Tasso-M20 demonstrated great concordance with serum for sMAdCAM-1 measurement. However, a bias was observed in Mitra dried blood samples, presumably due to the different sample collection sites in comparison with venipuncture and Tasso devices. Our study highlights the potential of low volume sampling technologies for biomarker analysis, and underscores the importance of understanding the challenges and limitations of these technologies before integrating them into clinical studies.

At-home bodyweight interval exercise in the fed versus fasted state lowers postprandial glycemia and appetite perceptions in females

Limited research has characterized the metabolic health benefits of bodyweight interval exercise (BWE) performed outside of a laboratory setting. Metabolic responses to exercise can also be influenced by meal timing around exercise, but the interactive effects of BWE and nutrition are unknown. This study investigated the effects of BWE performed in the fasted or fed state on postprandial glycemia, post-exercise fat oxidation and appetite perceptions. Twelve females (23 ± 2 years; 22 ± 2 kg/m2) underwent two virtually-monitored trials that involved completing BWE (10 × 1 min, 1 min recovery) 5 min before (FastEX) or beginning BWE 10 min after (FedEX) a standardized breakfast. Heart rate and rating of perceived exertion (RPE) were measured during exercise and capillary glucose concentrations were measured for 2 h postprandial. Following exercise, appetite perceptions were assessed and Lumen expired carbon dioxide percentage (L%CO2) was measured as an index of fat oxidation. Heart rate (85 ± 5%) and RPE (14 ± 2) did not differ between conditions (p > 0.05). Postprandial glucose mean (6.1 ± 0.6 vs. 6.8 ± 0.8 mmol/L, p = 0.03), peak (7.4 ± 1.2 vs. 8.5 ± 1.5 mmol/L, p = 0.01), and area under the curve (AUC) (758 ± 72 vs. 973 ± 82 mmol/L × 2 h, p = 0.004) were lower in FedEX versus FastEX. Appetite perceptions were lower in FedEX versus FastEX (-87.63 ± 58.51 vs. -42.06 ± 34.96 mm, p = 0.029). Post-exercise L%CO2 was transiently decreased 30 min post-exercise in both conditions (4.03 ± 0.38 vs. 4.29 ± 0.34%, p = 0.0023), reflective of increased fat oxidation following BWE. These findings demonstrate that BWE performed in the fed compared to the fasted state lowered postprandial glycemia and appetite perceptions in females.

Improving the Bias of Comparator Methods in Analytical Performance Assessments Through Recalibration

BACKGROUND

In analytical performance studies, the choice of comparator method plays an important role, as studies have shown that there exist relevant systematic differences (bias) between laboratory analyzers. The feasibility of retrospective recalibration of measurement results through comparison with methods or materials of higher metrological order to minimize bias was therefore assessed.

METHOD

Existing data from performance studies of continuous and blood glucose monitoring systems were retrospectively analyzed. Comparison with a higher-order method was performed for two different data sets. In both cases, subject samples were measured, and a subset was also measured on a higher-order method. Recalibration based on higher-order materials (standard reference material [SRM]) was conducted for two different data sets containing results from SRM and subject samples. Linear regression analysis was performed for each device separately. Resulting equations were applied to the respective complete data set of subject samples. Bias between devices in a data set across all subject samples was assessed before and after recalibration.

RESULTS

Bias between devices was reduced from -3.6% to +0.6% in one data set and from +11.0% to +0.3% in the other by recalibration based on higher-order method. Using higher-order materials, bias was also reduced by recalibration, but mixed results were found: Bias was reduced from -3.1% to -0.1% in one data set and from -4.3% to -2.7% in the other.

CONCLUSIONS

Recalibration did lead to a decrease in bias and thus can reduce the impact of the choice of comparator method. The procedure should be verified in a prospectively designed setting.

Combining blood glucose and SpO2/FiO2 ratio facilitates prediction of imminent ventilatory needs in emergency room COVID-19 patients

The increasing requirement of mechanical ventilation (MV) due to the novel coronavirus disease (COVID-19) is still a global threat. The aim of this study is to identify markers that can easily stratify the impending use of MV in the emergency room (ER). A total of 106 patients with COVID-19 requiring oxygen support were enrolled. Fifty-nine patients were provided MV 0.5 h (interquartile range: 0.3 to 1.4) post-admission. Clinical and laboratory data before intubation were collected. Using a multivariate logistic regression model, we identified four markers associated with the impending use of MV, including the ratio of peripheral blood oxygen saturation to fraction of inspired oxygen (SpO2/FiO2 ratio), alanine aminotransferase, blood glucose (BG), and lymphocyte counts. Among these markers, SpO2/FiO2 ratio and BG, which can be measured easily and immediately, showed higher accuracy (AUC: 0.88) than SpO2/FiO2 ratio alone (AUC: 0.84), despite no significant difference (DeLong test: P = 0.591). Moreover, even in patients without severe respiratory failure (SpO2/FiO2 ratio > 300), BG (> 138 mg/dL) was predictive of MV use. Measuring BG and SpO2/FiO2 ratio may be a simple and versatile new strategy to accurately identify ER patients with COVID-19 at high risk for the imminent need of MV.

Neonatal Endocrine Diseases

Endocrine diseases are rare and can present very subtly in the neonatal period. Most are diagnosed using newborn screening in the United States; however, some infants may present with false negatives or more subtle findings. Endocrine etiologies should be considered during the management of critically ill infants. This article will give an overview of endocrine emergencies encountered in the neonatal period, including disorders of glucose metabolism, thyroid disorders, adrenal disorders, and pituitary disorders.

Hyperglycemia and prematurity: a narrative review

Hyperglycemia is commonly encountered in extremely preterm newborns and physiologically can be attributed to immaturity in several biochemical pathways related to glucose metabolism. Although hyperglycemia is associated with a variety of adverse outcomes frequently described in this population, evidence for causality is lacking. Variations in definitions and treatment approaches have further complicated the understanding and implications of hyperglycemia on the immediate and long-term effects in preterm newborns. In this review, we describe the relationship between hyperglycemia and organ development, outcomes, treatment options, and potential gaps in knowledge that need further research. IMPACT: Hyperglycemia is common and less well described than hypoglycemia in extremely preterm newborns. Hyperglycemia can be attributed to immaturity in several cellular pathways involved in glucose metabolism in this age group. Hyperglycemia has been shown to be associated with a variety of adverse outcomes frequently described in this population; however, evidence for causality is lacking. Variations in definitions and treatment approaches have complicated the understanding and the implications of hyperglycemia on the immediate and long-term effects outcomes. This review describes the relationship between hyperglycemia and organ development, outcomes, treatment options, and potential gaps in knowledge that need further research.

Instrument-free single-step direct estimation of the plasma glucose level from one drop of blood using smartphone-interfaced analytics on a paper strip

We demonstrated an instrument-free miniaturized adaptation of the laboratory gold standard methodology for the direct estimation of plasma glucose from a drop of whole blood using a low-cost single-user-step paper-strip sensor interfaced with a smartphone. Unlike a majority of the existing glucose meters that use whole blood-based indirect sensing technologies, our direct adaptation of the gold-standard laboratory benchmark could eliminate the possibilities of cross interference with other analytes present in the whole blood by facilitating an in situ plasma separation, capillary flow and colorimetric reaction occurring concomitantly, without incurring additional device complexity or embodiment. The test reagents were dispensed in lyophilized form, and the resulting paper strips were found to be stable over three months stored in a normal freezer, rendering easy adaptability commensurate with the constrained supply chains in extreme resource-poor settings. Quantitative results could be arrived at via a completely-automated mobile-app-based image analytics interface developed using dynamic machine learning, obviating manual interpretation. The tests were demonstrated to be of high efficacy, even when executed by minimally trained frontline personnel having no special skill of drawing precise volume of blood, on deployment at under-resourced community centres having no in-built or accessible healthcare infrastructure. Clinical validation using 220 numbers of human blood samples in a double-blinded manner evidenced sensitivity and specificity of 98.11% and 96.7%, respectively, as compared to the results obtained from a laboratory-benchmarked biochemistry analyser, establishing its efficacy for public health and community disease management in resource-limited settings without any quality compromise of the test outcome.

Oral glucose tolerance test to diagnose gestational diabetes mellitus: Impact of variations in specimen handling

To improve birth outcomes, all pregnant women without known diabetes are recommended for an oral glucose tolerance test (OGTT) to screen for hyperglycaemia in pregnancy (diabetes in pregnancy or gestational diabetes mellitus (GDM)). This narrative review presents contemporary approaches to minimise preanalytical glycolysis in OGTT samples with a focus on GDM diagnosis using criteria derived from the Hyperglycemia and Adverse Pregnancy Outcomes (HAPO) study. The challenges of implementing each approach across a diverse Australian healthcare setting were explored. Many Australian sites currently collect and transport OGTT samples at ambient temperature in sodium fluoride (NaF) tubes which is likely to lead to missed diagnosis of GDM in a significant proportion of cases. Alternative preanalytical solutions should be pragmatic and tailored to individual settings and as close as possible to the preanalytical conditions of the HAPO study for correct interpretation of OGTT results. Rapid centrifugation of barrier tubes to separate plasma could be suitable in urban settings provided time to centrifugation is strictly controlled. Tubes containing NaF and citrate could be useful for remote or resource poor settings with long delays to analysis but the impact on the interpretation of OGTT results should be carefully considered. Testing venous blood glucose at the point-of-care bypasses the need for glycolytic inhibition but requires careful selection of devices with robust analytical performance. Studies to evaluate the potential error of each solution compared to the HAPO protocol are required to assess the magnitude of misdiagnosis and inform clinicians regarding the potential impact on patient safety and healthcare costs.

Reliability of continuous glucose monitoring system in the inpatient setting

Aims/Hypothesis

Hyperglycemia and hypoglycemia are associated with increased morbidity and mortality in the inpatient setting. Standard point of care capillary glucose testing (POCT) is commonly used in hospitalized patients to monitor their glucose levels. The goal of this study was to examine the relationships between the glucose readings obtained by a continuous glucose monitoring system (CGMS) (Freestyle Libre) and the capillary blood glucose results obtained by the inpatient glucose POCT meter (Accuchek Inform II) as well as between CGMS readings and the serum glucose values obtained by the hospital laboratory. Study participants had either primary or secondary diagnosis of diabetes mellitus and were admitted to non-critical units. We hypothesized that there exists an acceptable agreement between the capillary blood glucose results obtained by the inpatient glucose POCT meter (Accuchek Inform II) and the readings obtained by the CGMS (Freestyle Libre); and that there exists an acceptable agreement between the serum glucose levels and the glucose values obtained by the CGMS.

Methods

This was an Institutional Review Board approved prospective cohort study for the non– critical inpatient setting. Fifty-two hospitalized patients with diabetes were recruited. After informed consent was obtained, patients were instructed on the application and use of the CGMS. The data were assessed using a standard regression analysis and modified Bland Altman analysis. All analyses were conducted using SAS, release 3.8 Enterprise Edition (SAS Institute Inc., Cary, NC).

Results

Fifty-two subjects recruited into the study represented a sample of convenience. There were a total of 467 AccuChek-Libre pairs, The regression analysis showed a negative bias between.

Libre and AccuChek, R² = 0.83, with Libre glucose readings on average being lower than those of AccuChek. Using Bland-Altman analysis, 42% of the 467 Libre-AccuChek pairs had a difference in glucose reading more than 15%. Mean absolute relative difference (MARD) between Libre and AccuChek was 15.6%; mean relative difference (MRD) between Libre and AccuChek was −11.4%.

The regression analysis showed a negative bias between Libre and serum glucose, R² = 0.89. Using Bland Altman analysis, 36% of the 44 Libre-serum pairs had a difference in glucose reading more than 15%. Mean absolute relative difference (MARD) between Libre and serum glucose was 13.2%; mean relative difference (MRD) between Libre and serum glucose was −12.5%.

A review of the data pairs showed that 71/467 Accuchek-Libre pairs had one result that was either below 70 mg/dl or above 200 mg/dl (combined American Diabetes Association-ADA-, American College of Physicians-ACP- and American College of Endocrinology-AACE- goals). Thus 85%, of these pairs would have yielded results that engendered the same intervention (e.g. treatment for hypoglycemia or hyperglycemia). Likewise 5/45 Serum-Libre pairs had one result that was either below 70 mg/dl or above 200 mg/dl; thus 89% of these pairs would have yielded results requiring the same intervention.

Conclusion/Interpretation

These findings confirm the existent literature and indicate acceptable agreement between the standard POCT and the CGMS as well as between serum glucose and the CGMS values. Because of the advantages of the CGMS over capillary blood glucose testing (reduced patient discomfort and reduced staff exposure to patients in isolation) CGMS use may be preferable to the current bedside capillary blood glucose testing in hospitalized patients with diabetes mellitus. As with other laboratory measures, clinical judgement needs to be exercised when the laboratory values are used to guide patient care.

Effects of Different Methods Used to Take Blood Samples on Blood Glucose Measurements

The purpose of this study is to compare whether or not there is a difference between venous and capillary blood samples in blood glucose measurements and investigate the effects of different aseptic methods used in skin cleaning before collecting blood samples on measurement results. This quasi-experimental study was conducted with 109 patients. The capillary first and second blood drop values taken from the patients after fasting and at 2 hours following 75 g oral glucose tolerance test (OGTT) and capillary and venous blood glucose values were compared. There was no significant difference between the median venous blood glucose value and the capillary second blood drop value taken after wiping the finger with alcohol. There was no significant difference between the first and second blood drop values of capillary blood glucose 2 hours after OGTT.

Differences in circulating fatty acid-binding protein 4 concentration in the venous and capillary blood immediately after acute exercise

Background

Circulating fatty acid-binding protein 4 (FABP4) is a marker for various diseases. It would be highly useful to have simple and less invasive techniques for the assessment of FABP4 concentrations in the clinical research setting. The purpose of the present study was to assess the concordance of circulating FABP4 concentrations in venous and capillary blood both at rest and immediately after acute exercise in healthy young males.

Results

Thirty-eight healthy young male adults aged from 19 to 25 years (mean age, 20.8 ± 1.2 years) were recruited. Paired blood samples were taken from the cubital vein (venous) and fingertip (capillary) blood at rest (resting state) and immediately after incremental exercise (exercising state). Blood samples were analyzed to determine the circulating FABP4 concentration using an enzyme-linked immunosorbent assay. Pearson’s correlation coefficients for circulating FABP4 concentrations between venous and capillary blood samples indicated a strong positive correlation in both the resting and exercising state (resting state: r = 0.982, exercising state: r = 0.989, both p < 0.001). The mean FABP4 concentration was similar between venous and capillary blood in the resting state (p = 0.178), whereas it was significantly higher in capillary blood than in venous blood in the exercising state (p < 0.001). Furthermore, Bland–Altman plots showed a non-significant bias (− 0.07 ± 0.61 ng/mL, p = 0.453) in the resting state, whereas a significant bias (− 0.45 ± 0.61 ng/mL, p < 0.001) was observed in the exercising state.

Conclusions

These results indicate that capillary blood sampling can slightly overestimate circulating FABP4 concentrations under a physiologically dynamic state. However, the association between the venous and capillary blood in terms of FABP4 concentration was very strong, suggesting that capillary blood sampling can detect changes in FABP4 concentration in both physiologically steady and dynamic states.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40101-021-00255-z.

Glucose measurement in body fluids: A ready reckoner for clinicians

BACKGROUND AND AIMS

Blood glucose measurement is central to the diagnosis and management of patients with diabetes. Considering that a clinician relies heavily on blood (or rarely other body fluid) glucose values for decision making, an understanding of the basic aspects of glucose measurement in body fluids is necessary.

METHODS

A literature search was conducted in PubMed for articles in English on measurement of glucose in body fluids.

RESULTS

Glucose can be measured in several body fluids, namely blood, interstitial fluid, urine, cerebrospinal fluid, pleural fluid and ascitic fluid in appropriate clinical settings. For blood glucose measurement, the present-day enzymatic methods have replaced the older reducing and condensation methods on account of their better accuracy. It is important to consider preanalytical factors such as sample collection, storage and transport when analyzing a laboratory blood glucose report. The measurement of glucose in interstitial fluid using continuous glucose monitoring system (CGMS) enables better understanding of glucose trends and fluctuations. The CGMS data should be reported using standard metrics which include parameters such as mean 24-h glucose, glycemic variability and time-in, below and above range. The measurement of glucose in urine sample is rarely ever used these days and should be reserved for exceptional circumstances.

CONCLUSION

This review provides a detailed account of various aspects of glucose measurement including their evolution, pitfalls, and their utility in current clinical practice.

The Oral Glucose Tolerance Test-Is It Time for a Change?-A Literature Review with an Emphasis on Pregnancy

Globally, gestational diabetes (GDM) is increasing at an alarming rate. This increase is linked to the rise in obesity rates among women of reproductive age. GDM poses a major global health problem due to the related micro- and macro-vascular complications of subsequent Type 2 diabetes and the impact on the future health of generations through the long-term impact of GDM on both mothers and their infants. Therefore, correctly identifying subjects as having GDM is of utmost importance. The oral glucose tolerance test (OGTT) has been the mainstay for diagnosing gestational diabetes for decades. However, this test is deeply flawed. In this review, we explore a history of the OGTT, its reproducibility and the many factors that can impact its results with an emphasis on pregnancy.

Land O'Lakes Workshop on Microsampling: Enabling Broader Adoption

The microsampling workshop generated recommendations pertaining to blood sampling site (venous blood versus capillary blood), when to conduct a bridging study, statistical approaches to establish correlation/concordance and deciding on sample size, opportunities and challenges with patient-centric sampling, and how microsampling technology can enrich clinical drug development. Overall, the goal was to provide clarity and recommendations and enable the broader adoption of microsampling supporting patients’ needs, convenience, and the transformation from clinic-centric to patient-centric drug development. The need and adoption of away-from-clinic sampling techniques has become critical to maintain patient safety during the current COVID-19 pandemic.

Capillary glucose concentration during oral glucose tolerance test for the diagnosis of gestational diabetes

OBJECTIVE

To assess concordance between two point-of-care testing (POCT) devices and the standard laboratory method in screening for gestational diabetes mellitus (GDM) in Huesca.

METHODS

Pregnant women who met criteria for an oral glucose tolerance test (OGTT) and attended the laboratory between October 2017 and November 2018 were recruited in this prospective observational study. Glucose was measured in venous (laboratory) and capillary blood (Accu-Chek or Contour Next glucometers). GDM was diagnosed attending to NDDG criteria for venous samples or capillary-specific cut-off. Linear regression, Passing-Bablok, Bland-Altman, and the kappa coefficient were used to study concordance between POCT and laboratory method.

RESULTS

Data from 109 women were analyzed (57 for Accu-Chek, 52 for Contour Next). Statistical analyses showed good agreement between both POCT and laboratory method. There were no statistical differences in fasting glucose measurements between capillary and venous samples and both POCT devices meet the ISO 15197 standard. Accu-Chek showed good agreement (k=0.629) regarding the laboratory method in classifying GDM, with an acceptable inter-evaluator bias of 3.5% (P<0.001).

CONCLUSION

POCT can be used to obtain fasting values and reduce overall waiting times for patients. Additionally, Accu-Chek can be used to diagnose GDM in remote areas applying specific cut-off values.

Comparison of Accuracy Guidelines for Hospital Glucose Meters

When used in hospital settings, glucose meter performance issues involve analytic comparability to lab-based testing, patient and sample variables, and clinical affects such as insulin treatment protocol outcomes and morbidity or outcome risk factors. Different tools are available to assess these issues, including accuracy and precision statistics along with clinical risk measures such as error grids or simulation testing. Regulatory, guidance, and professional bodies have advocated a number of varying recommendations for glucose meter performance in different situations and under different patient conditions. These are summarized and compared, but reconciling these guidelines can be confusing or difficult for providers. Blood glucose meters are useful in the management of patients in acute or assisted care facilities, but users must appreciate the variables that affect measurements and provide for oversight that can manage risk factors and maintain meter performance expectations.

Clinical and Analytical Impact of Moving from Jaffe to Enzymatic Serum Creatinine Methodology

Background

Identification and monitoring of chronic kidney disease (CKD) requires accurate quantification of serum creatinine. The poor specificity of Jaffe creatinine methods is well documented, and guidelines recommend enzymatic methodology. We describe our experience of moving from Jaffe to enzymatic creatinine methodology. We present comparison of &gt;5000 paired Jaffe and enzymatic creatinine results, examine interferences, and attempt to assess clinical consequences of changing methodology.

Methods

Overall, 5303 serum samples received for routine creatinine measurement were analyzed using Jaffe and enzymatic methods with an Abbott Architect autoanalyzer. Associated results for glucose, total bilirubin, triglycerides, total protein, and hemolytic, icteric, and lipemic indexes were extracted from the laboratory database. CKD staging was estimated for each sample to assess potential clinical effects.

Results

The methods correlated well (r = 0.996) and showed good agreement (Passing-Bablok fit, y = 0.935x + 0.074). Paired analysis, however, showed significant differences (P &lt; 0.001), and approximately 20% of results differed by more than ±10%. Multivariate analysis demonstrated independent associations between difference in creatinine results, glucose (P &lt; 0.0001), and hemolytic index (P = 0.009). Glucose demonstrated positive interference in the Jaffe method, and hemolysis produced negative interference in the enzymatic method. Little or no association was observed with other analytes. CKD staging differed in 4% of samples.

Conclusions

Differences between Jaffe and enzymatic serum creatinine results exceed the recommended 5% target for a significant proportion of samples, particularly at concentrations &lt;1.13 mg/dL (100 µmol/L). Both glucose and hemolysis contribute to the variance in results. Although the clinical impact of these differences seems small, laboratories should continue moving toward enzymatic creatinine estimation to ensure the best estimate of renal function.

Comparison of plasma fatty acid binding protein 4 concentration in venous and capillary blood

Circulating fatty acid binding protein 4 (FABP4) is associated with various diseases and simple and less invasive techniques for assessment of FABP4 concentration are required in clinical research setting. The purpose of the present study was to assess the correlation of plasma FABP4 concentration between venous and capillary blood in healthy young adults. Twenty-eight healthy young adults aged from 20 to 26 years (mean age, 22.2 ± 1.4 years, 14 males and 14 females) were included. Paired resting blood samples were taken from the cubital vein (venous) and fingertip (capillary) blood. Plasma FABP4 concentration in both blood was analyzed by enzyme-linked Immunosorbent assay. Plasma FABP4 concentration did not differ significantly between venous and capillary blood (−0.11± 0.75 ng/mL, p = 0.447, 95%CI: -0.402–0.182). Pearson’s correlation coefficient for plasma FABP4 concentration between venous and capillary blood samples suggests strong correlation (r = 0.961, p < 0.001). The Bland & Altman plot showed a non-significant bias (−0.11 ± 0.75 ng/mL, p = 0.684) and the 95% limits of agreement ranged from −1.59 to 1.37 ng/mL. FABP4 concentration in both venous and capillary blood was significantly higher in females than in males (venous blood: p = 0.041; capillary blood: p = 0.049). These results suggest that capillary blood sampling can detect gender difference and is useful for the assessment of FABP4 concentration.

The screening and management of newborns at risk for low blood glucose

Hypoglycemia in the first hours to days after birth remains one of the most common conditions facing practitioners across Canada who care for newborns. Many cases represent normal physiologic transition to extrauterine life, but another group experiences hypoglycemia of longer duration. This statement addresses key issues for providers of neonatal care, including the definition of hypoglycemia, risk factors, screening protocols, blood glucose levels requiring intervention, and managing care for this condition. Screening, monitoring, and intervention protocols have been revised to better identify, manage, and treat infants who are at risk for persistent, recurrent, or severe hypoglycemia. The role of dextrose gels in raising glucose levels or preventing more persistent hypoglycemia, and precautions to reduce risk for recurrence after leaving hospital, are also addressed. This statement differentiates between approaches to care for hypoglycemia during the 'transitional' phase-the first 72 hours post-birth-and persistent hypoglycemia, which occurs or presents for the first time past that point.

Le dépistage et la prise en charge des nouveau-nés à risque d’hypoglycémie

L’hypoglycémie entre les premières heures et les premiers jours suivant la naissance demeure l’une des principales affections qu’observent les praticiens du Canada qui s’occupent de nouveau-nés. Bien des cas vivent une transition physiologique normale à la vie extra-utérine, mais un groupe présente une hypoglycémie pendant une plus longue période. Le présent document de principes expose les principaux enjeux auxquels sont exposés les dispensateurs de soins néonatals, y compris la définition d’hypoglycémie, les facteurs de risque, les protocoles de dépistage, les valeurs de glycémie nécessitant une intervention et la gestion des soins pour cette affection. Les auteurs passent en revue le dépistage, la surveillance et les protocoles d’intervention pour mieux distinguer, prendre en charge et traiter les nouveau-nés à risque d’hypoglycémie persistante, récurrente ou marquée. Ils abordent également le rôle des gels de dextrose pour accroître la glycémie ou prévenir une hypoglycémie plus persistante, de même que les précautions à prendre pour réduire les risques de récurrence après le congé de l’hôpital. Le présent document de principes distingue les approches des soins de l’hypoglycémie pendant la « phase de transition » (les 72 premières heures de vie) de celles de l’hypoglycémie persistante, qui se manifeste ou est constatée pour la première fois après cette période.

Technical note: Glucose concentration in dairy cows measured using 6 handheld meters designed for human use

The objective was to evaluate the precision and accuracy of 6 handheld glucose meters, designed for human use [Accu-Chek Aviva Plus (AC), Roche Diabetes Care, Mannheim, Germany; Aga Matrix (AM), AgaMatrix Inc., Salem, NH; Contour Next (CT), Bayer HealthCare LLC, Leverkusen, Germany; FreeStyle Precision Neo (FS), Abbott Diabetes Care Ltd., Alameda, CA; Nova Max Plus (NM), Nova Biomedical Corporation, Waltham, MA; and Precision Xtra (PX), Abbott Diabetes Care Ltd., Witney, UK] to measure blood glucose concentration in dairy cows. Blood samples from Jersey and Jersey × Holstein crossbreed cows (n = 97 for all; except CT, n = 71) were collected and analyzed in triplicate using the 6 handheld glucose meters evaluated. Plasma glucose was also measured with the laboratory reference method (hexokinase glucose-6-phosphate dehydrogenase). Based on the intra-assay coefficient of variation (CV), precision varied across handheld glucose meters: AC (2.2%), CT (4.0%), PX (4.7%), FS (5.6%), AM (6.2%), and NM (6.7%). Lin's concordance correlation coefficients between handheld glucose meters and the reference method were 0.75 for FS, 0.74 for PX, 0.62 for AC, 0.55 for CT, 0.53 for NM, and 0.48 for AM. Based on Passing-Bablok regression, the AM and PX meters showed bias in the measurements of blood glucose. Bland-Altman plots indicated a negative bias (FS = -0.25 mmol/L; CT = -0.60 mmol/L) or a positive bias (AM = 0.29 mmol/L; PX = 0.33 mmol/L; NM = 0.52 mmol/L; AC = 0.65 mmol/L) between handheld glucose meters and the reference method. All handheld glucose meters evaluated had wide limits of agreement (LoA) ranging from -0.18 to 1.47 mmol/L (AC, narrowest LoA) to -1.25 to 1.82 mmol/L (AM, widest LoA). Bias was the major contributor to the total observed error (TE_obs), accounting for 81.5% of the TE_obs in AC, 72.0% in CT, 64.9% in AM, 61.1% in NM, 57.8% in PX, and 56.2% in FS. Overall, although some handheld meters (AC, CT, and PX) showed satisfactory precision, none were accurate measuring glucose. Future studies should evaluate whether incorporating algorithms designed for cattle can improve accuracy and precision of handheld glucose meters.

Comment on "accuracy and precision of four main glucometers used in a sub-Saharan African country: a cross-sectional study" by Choukem et al

In their article, Choukem et al. report of assessments of the analytical quality of blood glucose monitoring systems. Although there are some commendable aspects regarding the methodology, some major shortcomings could preclude the conclusions drawn by Choukem et al. Nevertheless, independent assessments of the performance of blood glucose monitoring systems are an important issue.

Diabetes mellitus and laboratory medicine in sub-Saharan Africa: challenges and perspectives

Diabetes mellitus is an increasing public health problem in sub-Saharan Africa with a substantial socioeconomic burden. Although laboratory medicine has been recognized as one of the six key public health functions, there are still gaps in strengthening of laboratory services in developing countries. In the last decades, a lot of progress has been made in the diagnostic field of infectious diseases, whereas the diagnosis of noncommunicable diseases is still insufficient and uneven. This article analyses the challenges encountered in diagnosing and monitoring of diabetes mellitus in sub-Saharan Africa and explores new alternative diagnostic tools.

Impact of Glucose Measuring Systems and Sample Type on Diagnosis Rates of Diabetes Mellitus

INTRODUCTION

The use of glucose point-of-care testing (POCT) devices for the diagnosis of diabetes mellitus (DM) is an ongoing controversy. In patient management, glucose concentrations are determined by POCT and core laboratory glucose methods, and the values are commonly compared even though the samples collected are different, namely, capillary whole blood and venous plasma. In individual patients it is difficult to distinguish between factors that can influence the results, such as sample type and measuring procedure. In this study, glucose concentrations obtained using POCT and core laboratory instruments were assessed to duplicate typical scenarios experienced in healthcare. Corresponding diagnosis rates of impaired glucose tolerance (IGT) and DM based on fixed, method-independent cutoffs were compared.

METHODS

Glucose concentration was measured by the 2-h oral glucose tolerance test (OGTT) in samples collected from an inpatient cohort and a cohort from the general population. Two POCT methods, namely, a handheld unit-use glucometer and a small bench-top analyzer with batch reagents, and two core laboratory procedures were used to measure glucose concentrations. The sample types were whole blood and plasma samples collected from venous and capillary blood. The glycated hemoglobin level in whole blood was also determined.

RESULTS

A total of 231 subjects were included in the study. The 2-h OGTT glucose concentrations in the capillary whole blood samples showed a positive bias of 0.8 mmol/L compared to those obtained using core laboratory plasma glucose methods, leading to increased rates of diabetes diagnosis. This bias decreased to 0.2 mmol/L when venous blood was used in the tests. A change in the method used by the core laboratory introduced a negative bias of 0.5 mmol/L and, consequently, a lower diagnosis rates.

DISCUSSION AND CONCLUSION

Venous blood samples measured at the point-of-care are the most suitable sample type for the measurement of the glucose concentration in the 2-h OGTT. The investigated unit-use POCT method is suitable for the diagnosis of IGT and DM when venous blood samples are collected. Importantly, changes in measurement procedures can introduce a bias and affect diagnosis rates, thereby emphasizing the need for further harmonization of glucose methods. A plain language summary is available for this article.

The Accuracy of Point-of-Care Equipment for Glucose Measurement in Screening for Dysglycemia in Patients with Coronary Artery Disease

BACKGROUND

Point-of-care equipment for measuring glucose saves time and costs for both patients and professionals and minimizes preanalytic errors when screening for or managing dysglycemia, that is, impaired glucose tolerance and type 2 diabetes. The accuracy of such devices has, however, been questioned compared with analyses at an accredited hospital laboratory.

OBJECTIVE

To investigate the agreement between glucose measurements made by the point-of-care HemoCue^® Glucose 201 RT System (HemoCue, Ängelholm, Sweden) and local hospital laboratories.

MATERIAL

Patients with established coronary artery disease (CAD) recruited in Sweden and the United Kingdom within the auspices of the European Action on Secondary and primary Prevention by Intervention to Reduce Events (EUROASPIRE) V survey (n = 87; 18-80 years) with or without previously known dysglycemia were investigated. Plasma glucose values collected in the fasting state (n = 85) and 60 (n = 57) and 120 (n = 72) min after a glucose load were analyzed both using HemoCue monitors and local hospital laboratories. The two measurement techniques were compared using a bias plot according to Bland-Altman, the surveillance error grid, and Spearman correlation test.

RESULTS

The bias plot method showed small differences between the HemoCue and local hospital laboratory methods, the HemoCue and central hospital laboratory, and the local hospital laboratories and the central hospital laboratory. In the surveillance error grid, 98.6% of the values were in the deep green zone, indicating no risk and the remaining values (1.4%) were within the light green zone, indicating "slight lower risk."

CONCLUSION

The HemoCue point-of-care system is accurate for dysglycemia screening in patients with CAD.

Evaluating the utility of a point-of-care glucometer for the diagnosis of gestational diabetes

OBJECTIVE

To investigate the performance of the Roche Accuchek Active glucometer in diagnosing gestational diabetes mellitus (GDM) versus the gold-standard laboratory test.

METHODS

In a prospective cohort observational study at a primary healthcare clinic in Johannesburg, South Africa, pregnant women, excluding known diabetics, were recruited between 2013 and 2016. A 75-g 2-hour oral glucose tolerance test (OGTT) was scheduled at 24-28 gestational weeks. Glucose was measured in venous blood (laboratory) and capillary blood (glucometer). GDM was diagnosed via FIGO criteria. Diagnostic accuracy was evaluated by calculating the sensitivity, specificity, and coefficient of variance (CV) of the glucometer test, and by Bland-Altman plots.

RESULTS

Data from 529 women were analyzed. Of these, 141 (26.7%) and 79 (14.9%) were diagnosed with GDM by laboratory and glucometer measurements, respectively. The CV of the glucometer ranged from 15% to 17%. Bland-Altman plots showed a positive bias of the glucometer results at 0 hours, but a negative bias at 1 and 2 hours of the OGTT. The sensitivity and specificity of the glucometer for the diagnosis of GDM were 27.0% and 89.4%, respectively.

CONCLUSION

Use of the Roche Accuchek Active glucometer for the diagnosis of GDM cannot be recommended.

Venous, Arterialized-Venous, or Capillary Glucose Reference Measurements for the Accuracy Assessment of a Continuous Glucose Monitoring System

BACKGROUND

Different reference methods are used for the accuracy assessment of continuous glucose monitoring (CGM) systems. The effect of using venous, arterialized-venous, or capillary reference measurements on CGM accuracy is unclear.

METHODS

We evaluated 21 individuals with type 1 diabetes using a capillary calibrated CGM system. Venous or arterialized-venous reference glucose samples were taken every 15 min at two separate visits and assessed per YSI 2300 STAT Plus. Arterialization was achieved by heated-hand technique. Capillary samples were collected hourly during the venous reference visit. The investigation sequence (venous or arterialized-venous) was randomized. Effectiveness of arterialization was measured by comparing free venous oxygen pressure (PO2) of both visit days. Primary endpoint was the median absolute relative difference (ARD).

RESULTS

Median ARD using arterialized-venous reference samples was not different from venous samples (point estimated difference 0.52%, P = 0.181). When comparing the three reference methods, median ARD was also not different over the full glycemic range (venous 9.0% [n = 681], arterialized-venous 8.3% [n = 684], and capillary 8.1% [n = 205], P = 0.216), nor over the separate glucose ranges. Arterialization was successful (PO2 venous 5.4 kPa vs. arterialized-venous 8.9 kPa, P < 0.001). Arterialized-venous glucose was significantly higher than venous glucose and numerically higher than capillary glucose (arterialized-venous 142 mg/dL vs. venous 129 mg/dL [P < 0.001] and vs. capillary 134 mg/dL [P = 0.231]). Inconvenience related to arterialization included transient mild edema and redness of the hand in 4 out of 21 (19%) patients.

CONCLUSIONS

The use of venous, arterialized-venous, or capillary reference measurements did not significantly impact CGM accuracy. Venous reference seems preferable due to its ease of operation.

Sex differences in adolescents’ glycaemic and insulinaemic responses to high and low glycaemic index breakfasts: a randomised control trial

During puberty young people undergo significant hormonal changes which affect metabolism and, subsequently, health. Evidence suggests there is a period of transient pubertal insulin resistance, with this effect greater in girls than boys. However, the response to everyday high and low glycaemic index (GI) meals remains unknown. Following ethical approval, forty adolescents consumed a high GI or low GI breakfast, in a randomised cross-over design. Capillary blood samples were taken during a 2-h postprandial period, examining the glycaemic and insulinaemic responses. Maturity offset and homoeostatic model assessment (HOMA) were also calculated. The glycaemic response to the breakfasts was similar between boys and girls, as shown by similar peak blood glucose concentrations and incremental AUC (IAUC) following both high and low GI breakfasts (all P>0·05). Girls exhibited a higher peak plasma insulin concentration 30 min post-breakfast following both high GI (P=0·043, g=0·69) and low GI (P=0·010, g=0·84) breakfasts, as well as a greater IAUC following high GI (P=0·041, g=0·66) and low GI (P=0·041, g=0·66) breakfasts. HOMA was positively correlated with the insulinaemic responses (all P<0·0005) and maturity offset (P=0·037). The findings of the present study suggest that pubertal insulin resistance affects the postprandial insulinaemic responses to both high and low GI meals. Specifically, girls exhibit a greater insulinaemic response than boys to both meals, despite similar glycaemic responses. This study is the first to report the glycaemic and insulinaemic responses to everyday meals in boys and girls, supporting the recommendation for young people to base their diet on low GI carbohydrates.

Efficacy of fibre additions to flatbread flour mixes for reducing post-meal glucose and insulin responses in healthy Indian subjects

The incidence of type 2 diabetes mellitus (T2DM) is increasing worldwide, including in developing countries, particularly in South Asia. Intakes of foods generating a high postprandial glucose (PPG) response have been positively associated with T2DM. As part of efforts to identify effective and feasible strategies to reduce the glycaemic impact of carbohydrate-rich staples, we previously found that addition of guar gum (GG) and chickpea flour (CPF) to wheat flour could significantly reduce the PPG response to flatbread products. On the basis of the results of an exploratory study with Caucasian subjects, we have now tested the effect of additions of specific combinations of CPF with low doses of GG to a flatbread flour mix for their impacts on PPG and postprandial insulin (PPI) responses in a South-Asian population. In a randomised, placebo-controlled full-cross-over design, fifty-six healthy Indian adults consumed flatbreads made with a commercial flatbread mix (100 % wheat flour) with no further additions (control) or incorporating 15 % CPF in combination with 2, 3 or 4 % GG. The flatbreads with CPF and 3 or 4 % GG significantly reduced PPG (both ≥15 % reduction in positive incremental AUC, P<0·01) and PPI (both ≥28 % reduction in total AUC, P<0·0001) compared with flatbreads made from control flour. These results confirm the efficacy and feasibility of the addition of CPF with GG to flatbread flour mixes to achieve significant reductions in both PPG and PPI in Indian subjects.

Comparison of jugular and transverse facial venous sinus blood analytes in healthy and critically ill adult horses

OBJECTIVE

To compare blood gas, electrolyte, and metabolic analysis results between blood obtained by jugular and transverse facial venous sinus (TFVS) venipuncture in healthy adult horses and sick adult horses presented for emergency evaluation.

DESIGN

Prospective, experimental study, from June 2012 to October 2013.

SETTING

Large animal university teaching hospital.

ANIMALS

Ten healthy adult University-owned horses and 48 client-owned adult horses (≥2 years old) presenting to the large animal hospital emergency service for medical or surgical evaluation of systemic illness.

INTERVENTIONS

Venipunctures (jugular vein [JV] and TFVS) were performed using preheparinized syringes and obtained prior to institution of medical therapy. Samples were analyzed in random order within a 10-minute interval using a point-of-care blood gas analyzer (NOVA Critical Care Xpress) that also reports electrolyte and metabolite results. Comparisons between venipuncture sites were analyzed using the Student's paired t-test for normally distributed data and the Wilcoxon paired test for nonnormally distributed data. Bland-Altman analysis was used to assess agreement between venipuncture sites.

MEASUREMENTS AND MAIN RESULTS

There were no statistically significant differences found between variables for JV and TFVS in healthy horses. In sick horses, JV measurements were greater than TFVS for ionized calcium (P = 0.002) and glucose (P = 0.001), and less than TFVS for hematocrit (P = 0.015). Bland-Altman plots demonstrated small biases but overall agreement between sites.

CONCLUSIONS

The TFVS can be used interchangeably with JV for venous blood gas analysis in healthy horses. In sick horses, identified differences were small and likely not clinically important. The reliability of this point-of-care blood gas analyzer for measurement of hematocrit remains to be determined.

Soluble CD163, adiponectin, C-reactive protein and progression of dysglycaemia in individuals at high risk of type 2 diabetes mellitus: the ADDITION-PRO cohort

AIM/HYPOTHESIS

Our aim was to investigate the association between the macrophage-activation marker soluble CD163 (sCD163), adiponectin, C-reactive protein (CRP) and changes in glycaemia, insulin resistance and insulin secretion in individuals at high risk of type 2 diabetes mellitus.

METHODS

This prospective study included 1014 individuals at high risk of type 2 diabetes mellitus participating in the Danish arm of the Anglo-Danish-Dutch study of Intensive Treatment In PeOple with ScreeN-detected Diabetes in Primary Care (ADDITION-Europe trial) baseline examination in 2001-2006 and follow-up examination (ADDITION-Progression [ADDITION-PRO]) in 2009-2011. Baseline serum samples were analysed for sCD163, adiponectin and CRP. The associations between sCD163, adiponectin and CRP per doubling of concentration, and changes per year in HbA1c, fasting plasma glucose, 2 h glucose, fasting insulin, HOMA-IR and HOMA-β were assessed using a mixed-effects model.

RESULTS

A doubling of sCD163 concentration was positively associated with changes in fasting insulin (β = 1.078 per year, 95% CI 0.454, 1.702) and HOMA-β (β = 1.313 per year, 95% CI 0.537, 2.089), and a doubling of CRP concentration was positively associated with HbA 1c (β = 0.004 per year, 95% CI 0.001, 0.007) and fasting insulin (β = 0.267 per year, 95% CI 0.029, 0.504) after adjustment for age and sex. A doubling of adiponectin was inversely associated with changes in fasting glucose (β = −0.017 per year, 95% CI −0.028, −0.005), 2 h glucose (β = −0.063 per year, 95% CI −0.107, −0.019), fasting insulin (β = −1.558 per year, 95% CI −2.020, −1.096), HOMA-IR (β = −0.040 per year, 95% CI −0.062, −0.019) and HOMA-β (β = −1.009 per year, 95% CI −1.589, −0.429) after adjustment for age and sex. The associations were robust to adjustment for baseline waist circumference and smoking. Adjustment for CRP did not change the associations for sCD163 or adiponectin.

CONCLUSIONS/INTERPRETATION

Our findings indicate that mechanisms related to inflammation, including macrophage activation and adipocyte metabolism, may play a role in changes in glucose homeostasis in individuals at high risk of type 2 diabetes mellitus.

Uncertainty in Antibiotic Dosing in Critically Ill Neonate and Pediatric Patients: Can Microsampling Provide the Answers?

PURPOSE

With a decreasing supply of antibiotics that are effective against the pathogens that cause sepsis, it is critical that we learn to use currently available antibiotics optimally. Pharmacokinetic studies provide an evidence base from which we can optimize antibiotic dosing. However, these studies are challenging in critically ill neonate and pediatric patients due to the small blood volumes and associated risks and burden to the patient from taking blood. We investigate whether microsampling, that is, obtaining a biologic sample of low volume (<50 μL), can improve opportunities to conduct pharmacokinetic studies.

METHODS

We performed a literature search to find relevant articles using the following search terms: sepsis, critically ill, severe infection, intensive care AND antibiotic, pharmacokinetic, p(a)ediatric, neonate. For microsampling, we performed a search using antibiotics AND dried blood spots OR dried plasma spots OR volumetric absorptive microsampling OR solid-phase microextraction OR capillary microsampling OR microsampling. Databases searched include Web of Knowledge, PubMed, and EMbase.

FINDINGS

Of the 32 antibiotic pharmacokinetic studies performed on critically ill neonate or pediatric patients in this review, most of the authors identified changes to the pharmacokinetic properties in their patient group and recommended either further investigations into this patient population or therapeutic drug monitoring to ensure antibiotic doses are suitable. There remain considerable gaps in knowledge regarding the pharmacokinetic properties of antibiotics in critically ill pediatric patients. Implementing microsampling in an antibiotic pharmacokinetic study is contingent on the properties of the antibiotic, the pathophysiology of the patient (and how this can affect the microsample), and the location of the patient. A validation of the sampling technique is required before implementation.

IMPLICATIONS

Current antibiotic regimens for critically ill neonate and pediatric patients are frequently suboptimal due to a poor understanding of altered pharmacokinetic properties. An assessment of the suitability of microsampling for pharmacokinetic studies in neonate and pediatric patients is recommended before wider use. The method of sampling, as well as the method of bioanalysis, also requires validation to ensure the data obtained reflect the true result.

Assessing the Accuracy of Continuous Glucose Monitoring (CGM) Calibrated With Capillary Values Using Capillary or Venous Glucose Levels as a Reference

BACKGROUND

Using the standard venous reference for the evaluation of continuous glucose monitoring (CGM) systems could possibly negatively affect measured CGM accuracy since CGM are generally calibrated with capillary glucose and venous and capillary glucose concentrations differ. We therefore aimed to quantify the effect of using capillary versus venous glucose reference samples on estimated accuracy in capillary calibrated CGM.

METHODS

We evaluated 41 individuals with type 1 diabetes mellitus (T1DM) using the Dexcom G4 CGM system over 6 days. Patients calibrated their CGM devices with capillary glucose by means of the HemoCue system. During 2 visits, capillary and venous samples were simultaneously measured by HemoCue and compared to concomitantly obtained CGM readings. The mean absolute relative difference (MARD) was calculated using capillary and venous reference samples.

RESULTS

Venous glucose values were 0.83 mmol/L (15.0 mg/dl) lower than capillary values over all glycemic ranges, P < .0001. Below 4 mmol/l (72 mg/dl), the difference was 1.25 mmol/l (22.5 mg/dl), P = .0001, at 4-10 mmol/l (72-180 mg/dl), 0.67 mmol/l (12.0 mg/dl), P < .0001 and above 10 mmol/l (180 mg/dl), 0.95 mmol/l (17.1 mg/dl), P < .0001. MARD was 11.7% using capillary values as reference compared to 13.7% using venous samples, P = .037. Below 4 mmol/l (72 mg/dl) MARD was 16.6% and 31.8%, P = .048, at 4-10 mmol/l (72-180 mg/dl) 12.1% and 12.6%, P = .32, above 10 mmol/l (180 mg/dl) 8.7% and 9.2%, P = .82.

CONCLUSION

Using capillary glucose concentrations as reference to evaluate the accuracy of CGM calibrated with capillary samples is associated with a lower MARD than using venous glucose as the reference. Capillary glucose concentrations were significantly higher than venous in all glycemic ranges.

Overestimation of Hypoglycemia in Infants with a High Hematocrit

Background

In neonates, hypoglycemia is an emergency condition requiring urgent treatment. Therefore, rapid and reliable blood glucose measurements are necessary. However, this step has been proven difficult because of both analytical and preanalytical variables. In our children's hospital, we incidentally observed cases of hypoglycemia that were not in line with the clinical picture of the infants. Remarkably, most of these infants had a high hematocrit.

Methods

Glucose concentrations were determined in blood samples from healthy participants that were collected in Li-heparin capillary and pediatric tubes. The effect of hematocrit on glucose consumption over time was studied by artificially increasing sample hematocrits. To study the effect of sample cooling, glucose concentrations were followed over time in samples stored at room temperature and on ice.

Results

In all samples, glucose concentrations declined with time. This effect was most dramatic [up to 18 mg/dL (1 mmol/L) in the first 30 min] in samples with high hematocrits and collected in capillary tubes. Cooling of samples clearly reduced glucose consumption; however, this was not evident in the first 30 min.

Conclusions

Overestimation of hypoglycemia in infants must be considered if samples are not centrifuged or are not analyzed immediately after sampling. The extent of overestimation is more pronounced in samples with a high hematocrit, collected in capillary tubes. Cooling of samples does not prevent glucose consumption in vitro during the first 30 min. These results emphasize that, for glucose analysis, prompt handling of samples of newborns with a high hematocrit is necessary.

Postprandial capillary-venous glucose gradient in Type 1 diabetes: magnitude and clinical associations in a real world setting

AIMS

To determine the magnitude of the peripheral glucose gradient in patients with Type 1 diabetes in a real world setting and to explore its relationship with insulin dose and macronutrient intake.

METHODS

All patients used mealtime analogue insulin. The glucose gradient was assessed using antecubital fossa venous and finger-stick capillary samples, collected concurrently at room temperature. Baseline sampling occurred before the administration of an insulin dose and breakfast of the patient's choosing. Breakfast was consumed an average of 15 min after baseline. The macronutrient content of breakfast was documented. Sampling was repeated 1 and 2 h after baseline.

RESULTS

The mean (95% CI) plasma capillary-venous glucose gradient values for 43 patients were: pre-breakfast, 0.21 (0.08-0.34) mmol/l; 1 h after baseline, 0.87 (0.66-1.07) mmol/l; and 2 h after baseline, 0.52 (0.33-0.71) mmol/l. Glucose gradient and dietary carbohydrate intake (g/kg body weight) were positively correlated at both 1 h (P < 0.01) and 2 h after baseline (P < 0.01). No relationship was observed between this gradient and mealtime insulin dose, or the glucose concentration at either time point.

CONCLUSIONS

In patients with Type 1 diabetes, a clinically significant glucose gradient is present after the ingestion of a carbohydrate-rich meal. As postprandial capillary and venous plasma glucose concentrations are not equivalent, defining the site of sample collection is important.

[Accuracy and reliability between glucose meters: A study under normal clinical practice conditions]

INTRODUCTION

The glucose meters usually show a high accuracy, and in clinical practice, capillary and plasma glucose (PG) are used interchangeably. However, many variables can affect the validity of these devices. The aim of this study was to determine the accuracy and reliability of 3 glucose meters that are currently used in a primary care centre.

MATERIAL AND METHODS

A sample of venous blood and a drop of capillary blood were obtained from 59 participants. The drop was analysed in 3 glucose meters: 2 FreeStyle^® Optium (OP1 and OP2), and one Accu-Chek^® Aviva. The PG acted as the reference value, and the haematocrit and plasma levels of urea, bilirubin, uric acid and triglycerides were also analysed. We used the Passing-Bablok regression for accuracy and the intraclass correlation coefficient and the Bland-Altman method for reliability. The current American Diabetes Association standard of a total error of±5% was applied.

RESULTS

Differences in mean±standard deviation (mg/dL) and the systematic error were 5.8±7 and 5.8% (OP1); 6.2±8 and 5.9% (OP2); 8.3±8 and 6.3% (Accu-Chek^®). The OP1/OP2 pair showed the highest level of reliability, with an intraclass correlation coefficient=0.97, bias=-0.4mg/dL, and a width of the 95% limits of agreement of 28.6mg/dL. The highest levels of accuracy and reliability were observed in high glucose ranges (PG≥126mg/dL).

CONCLUSIONS

Despite their clinically acceptable mean difference compared to the PG, the 3 glucose meters did not fulfill the current American Diabetes Association standard. The regular performance of quality control tests of these devices is recommended.

Glucose concentration in capillary blood of dairy cows obtained by a minimally invasive lancet technique and determined with three different hand-held devices

BACKGROUND

Dairy cows have a massive demand for glucose at the onset of lactation. A poor adaption to this period leads to an excessive negative energy balance with an increased risk for ketosis and impaired animal health and production. Besides the measurement of ketones, analysing the glucose concentration in blood is reported as helpful instrument for diagnosis and differentiation of ketosis. Monitoring metabolic parameters requires multiple blood sampling. In other species, new blood sampling techniques have been introduced in which small amounts of blood are rapidly analysed using electronic hand-held devices. The objective of this study was to evaluate the suitability of capillary blood for blood glucose measurement in dairy cows using the hand-held devices FreeStyle Precision (FSP, Abbott), GlucoMen LX Plus (GLX, A. Menarini) and the WellionVet GLUCO CALEA, (WGC, MED TRUST). In total, 240 capillary blood samples were obtained from dry and fresh lactating Holstein-Friesian cows. Blood was collected from the skin of the exterior vulva by using a lancet. For method comparison, additional blood samples were taken from a coccygeal vessel and analyzed in a laboratory. Glucose concentrations measured by a standard laboratory method were defined as the criterion standard.

RESULTS

The Pearson correlation coefficients between the glucose concentrations analyzed in capillary blood with the devices and the reference were 73% for the FSP, 81% for the GLX and 41% for the WGC. Bland-Altman plots showed biases of -18.8 mg/dL for the FSP, -11.2 mg/dL for the GLX and +20.82 mg/dL for the WGC. The optimized threshold determined by a Receiver Operating Characteristics analysis to detect hyperglycemia using the FSP was 43 mg/dL with a sensitivity (Se) and specificity (Sp) of 76 and 80%. Using the GLX and WGC optimized thresholds were 49 mg/dL (Se = 92%, Sp = 85%) and 95 mg/dL (Se = 39%, Sp = 92%).

CONCLUSIONS

The results of this study demonstrate good performance characteristics for the GLX and moderate for the FSP to detect hyperglycemia in dairy cows using capillary blood. With the study settings, the WGC was not suitable for determination of glucose concentrations.

Glucose concentration in capillary blood of dairy cows obtained by a minimally invasive lancet technique and determined with three different hand-held devices

Background

Dairy cows have a massive demand for glucose at the onset of lactation. A poor adaption to this period leads to an excessive negative energy balance with an increased risk for ketosis and impaired animal health and production.

Besides the measurement of ketones, analysing the glucose concentration in blood is reported as helpful instrument for diagnosis and differentiation of ketosis. Monitoring metabolic parameters requires multiple blood sampling. In other species, new blood sampling techniques have been introduced in which small amounts of blood are rapidly analysed using electronic hand-held devices.

The objective of this study was to evaluate the suitability of capillary blood for blood glucose measurement in dairy cows using the hand-held devices FreeStyle Precision (FSP, Abbott), GlucoMen LX Plus (GLX, A. Menarini) and the WellionVet GLUCO CALEA, (WGC, MED TRUST). In total, 240 capillary blood samples were obtained from dry and fresh lactating Holstein-Friesian cows. Blood was collected from the skin of the exterior vulva by using a lancet. For method comparison, additional blood samples were taken from a coccygeal vessel and analyzed in a laboratory. Glucose concentrations measured by a standard laboratory method were defined as the criterion standard.

Results

The Pearson correlation coefficients between the glucose concentrations analyzed in capillary blood with the devices and the reference were 73 % for the FSP, 81 % for the GLX and 41 % for the WGC. Bland-Altman plots showed biases of −18.8 mg/dL for the FSP, -11.2 mg/dL for the GLX and +20.82 mg/dL for the WGC. The optimized threshold determined by a Receiver Operating Characteristics analysis to detect hyperglycemia using the FSP was 43 mg/dL with a sensitivity (Se) and specificity (Sp) of 76 and 80 %. Using the GLX and WGC optimized thresholds were 49 mg/dL (Se = 92 %, Sp = 85 %) and 95 mg/dL (Se = 39 %, Sp = 92 %).

Conclusions

The results of this study demonstrate good performance characteristics for the GLX and moderate for the FSP to detect hyperglycemia in dairy cows using capillary blood. With the study settings, the WGC was not suitable for determination of glucose concentrations.

Comparison of capillary and venous blood glucose levels using glucometer and laboratory blood glucose level in poisoned patients being in coma

Background:

Poisoning is one of the most common medical presentations in a hospital. Hypoglycemic patients are at increased risk of toxicity. The purpose of this study was to compare capillary blood glucose and venous blood glucose measurements using glucometer against laboratory blood glucose in case of poisoned patients being in coma.

Materials and Methods:

During the 6-month study period, a random sample of 98 patients was admitted in the Department of Poisoning Emergency and Clinical Toxicology of Noor Hospital, Isfahan University of Medical Sciences, Iran from May 2010. Data collected included age, gender, poisoning reason, vital signs, and Glasgow Coma Scale. Capillary blood samples were obtained from the fourth fingertip of the non-dominant hand. t-Test, paired t-test, Pearson's correlation analysis, and one-way analysis of variance (ANOVA) were used for analysis.

Results:

The mean of capillary blood glucose was 115.7 ± 50.2, of venous blood glucose measured by glucose meter was 117.8 ± 47.3, and of glucose measured in vitro was 115.8 ± 55.1. Mean of blood glucose showed no significant difference with the three mentioned methods. The correlation between capillary and intravenous blood glucose samples measured by glucometer was 0.93, between capillary blood glucose and in vitro measured venous blood glucose was 0.78, and between venous blood glucose measured by glucose meter and in vitro measured sample was 0.81. The mean of capillary and venous blood glucose levels measured by glucose meter, capillary and venous blood glucose levels measured in vitro, and venous blood glucose levels measured by glucose meter had no significant differences.

Conclusion:

Using venous blood sample and measuring the glucose level in it by glucometer is an acceptable and advisable method, and capillary blood glucose measurement by using glucometer is not recommended for patients in coma.

The Performance and Usability of a Factory-Calibrated Flash Glucose Monitoring System

INTRODUCTION

The purpose of the study was to evaluate the performance and usability of the FreeStyle(®) Libre™ Flash glucose monitoring system (Abbott Diabetes Care, Alameda, CA) for interstitial glucose results compared with capillary blood glucose results.

MATERIALS AND METHODS

Seventy-two study participants with type 1 or type 2 diabetes were enrolled by four U.S. clinical sites. A sensor was inserted on the back of each upper arm for up to 14 days. Three factory-only calibrated sensor lots were used in the study. Sensor glucose measurements were compared with capillary blood glucose (BG) results (approximately eight per day) obtained using the BG meter built into the reader (BG reference) and with the YSI analyzer (Yellow Springs Instrument, Yellow Springs, OH) reference tests at three clinic visits (32 samples per visit). Sensor readings were masked to the participants.

RESULTS

The accuracy of the results was demonstrated against capillary BG reference values, with 86.7% of sensor results within Consensus Error Grid Zone A. The percentage of readings within Consensus Error Grid Zone A on Days 2, 7, and 14 was 88.4%, 89.2%, and 85.2%, respectively. The overall mean absolute relative difference was 11.4%. The mean lag time between sensor and YSI reference values was 4.5±4.8 min. Sensor accuracy was not affected by factors such as body mass index, age, type of diabetes, clinical site, insulin administration, or hemoglobin A1c.

CONCLUSIONS

Interstitial glucose measurements with the FreeStyle Libre system were found to be accurate compared with capillary BG reference values, with accuracy remaining stable over 14 days of wear and unaffected by patient characteristics.

Effect of mobile reminders on screening yield during opportunistic screening for type 2 diabetes mellitus in a primary health care setting: A randomized trial

Objective. We wanted to study whether mobile reminders increased follow-up for definitive tests resulting in higher screening yield during opportunistic screening for diabetes. Methods. This was a facility-based parallel randomized controlled trial during routine outpatient department hours in a primary health care setting in Puducherry, India (2014). We offered random blood glucose testing to non-pregnant non-diabetes adults with age >30 years (667 total, 390 consented); eligible outpatients (random blood glucose ≥ 6.1 mmol/l, n = 268) were requested to follow-up for definitive tests (fasting and postprandial blood glucose). Eligible outpatients either received (intervention arm, n = 133) or did not receive mobile reminder (control arm, n = 135) to follow-up for definitive tests. We measured capillary blood glucose using a glucometer to make epidemiological diagnosis of diabetes. The trial was registered with Clinical Trial Registry of India (CTRI/2014/10/005138). Results. 85.7% of outpatients in intervention arm returned for definitive test when compared to 53.3% in control arm [Relative Risk = 1.61, (0.95 Confidence Interval — 1.35, 1.91)]. Screening yield in intervention and control arm was 18.6% and 10.2% respectively. Etiologic fraction was 45.2% and number needed to screen was 11.9. Conclusion. In countries like India, which is emerging as the diabetes capital of the world, considering the wide prevalent use of mobile phones, and real life resource limited settings in which this study was carried out, mobile reminders during opportunistic screening in primary health care setting improve screening yield of diabetes.

•

First RCT to determine the effect of mobile reminders on screening yield for diabetes mellitus.

•

Operational research conducted in real world primary health care setting.

•

Outpatients with random blood glucose ≥ 6.1 mmol/l among adults >30y were eligible for definitive tests.

•

Mobile reminders for eligible outpatients was introduced as a reminder system.

Vascular Glucose Sensor Symposium: Continuous Glucose Monitoring Systems (CGMS) for Hospitalized and Ambulatory Patients at Risk for Hyperglycemia, Hypoglycemia, and Glycemic Variability

Hyperglycemia, hypoglycemia, and glycemic variability have been associated with increased morbidity, mortality, length of stay, and cost in a variety of critical care and non-critical care patient populations in the hospital. The results from prospective randomized clinical trials designed to determine the risks and benefits of intensive insulin therapy and tight glycemic control have been confusing; and at times conflicting. The limitations of point-of-care blood glucose (BG) monitoring in the hospital highlight the great clinical need for an automated real-time continuous glucose monitoring system (CGMS) that can accurately measure the concentration of glucose every few minutes. Automation and standardization of the glucose measurement process have the potential to significantly improve BG control, clinical outcome, safety and cost.

Evaluation of 2 electronic handheld devices for diagnosis of ketonemia and glycemia in dairy goats

The objective of this study was to evaluate the suitability of the electronic handheld devices FreeStyle Precision (FSP; Abbott Germany, Wiesbaden, Germany) and GlucoMen LX Plus (GML; A. Menarini GmbH, Vienna, Austria) for the measurement of β-hydroxybutyrate (BHBA) in whole blood in dairy goats. Additionally, glucose concentration was analyzed with the FSP device. For method comparison, the samples were also analyzed in the laboratory by standard methods, which served as the gold standard in our study. A further objective was to evaluate the agreement between samples obtained by minimal invasive venipuncture of an ear vein and measurements of whole blood samples from the jugular vein (vena jugularis). In total, 173 blood sample pairs collected from 28 goats were obtained from an ear vein and from the jugular vein. The Spearman correlation coefficients (rsp) for BHBA concentrations determined with the FSP or GML and the gold standard were 0.95 and 0.85 for the ear vein and 0.98 and 0.88 for the jugular vein, respectively. Bland-Altman plots of differences showed a positive bias of 0.12 (ear vein) and 0.21 (jugular vein) when determination was performed with the FSP and a negative bias of 0.21 (ear vein) and 0.24 (jugular vein) when using the GML. For the FSP, applying the adjusted thresholds determined by ROC analysis of 0.9 (ear vein) and 1.0 mmol/L (jugular vein) allowed to distinguish between healthy goats and animals with hyperketonemia with sensitivities (Se) and specificities (Sp) for samples from the ear vein of 0.98 and 0.85, and from the jugular vein of 0.99 and 0.94, respectively. For the GML, adjusted thresholds were 0.5 mmol/L for the ear vein (Se=0.94, Sp=0.75) and 0.6 mmol/L for the jugular vein (Se=0.88, Sp=0.91). Repeated analyses of defined whole blood samples showed average inter- and intraassay coefficients of variation of 6.6 and 7.3% for FSP, and of 35.6 and 35.4% for GML, respectively. Test characteristics for determining glucose concentration with the FSP compared with the gold standard were poor (ear vein: rsp=0.41; jugular vein: rsp=0.51), with low validity to distinguish between hypo- and normoglycemia (Se=0.71, Sp=0.66). The present study showed good test characteristics for the FSP and moderate for the GML device for determining BHBA concentrations in whole blood. Additionally the results demonstrate the suitability of testing BHBA concentration in a blood drop obtained from an ear vein. Based on the results of this study, the FSP device is not suitable to differentiate normo- from hypoglycemia in goats.