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Background: This study aimed to develop the Point-of-Care Key Evidence Tool (POCKET); a multi-dimensional checklist to guide the evaluation of point-of-care tests (POCTs) incorporating validity, utility, usability, cost-effectiveness and patient experience. The motivation for this was to improve the efficiency of evidence generation in POCTs and reduce the lead-time for the adoption of novel POCTs. Methods: A mixed qualitative and quantitative approach was applied. Following a literature search, a three round Delphi process was undertaken incorporating a semi-structured interview study and two questionnaire rounds. Participants included clinicians, laboratory personnel, commissioners, regulators (including members of National Institute for Health and Care Excellence [NICE] committees), patients, industry representatives and methodologists. Qualitative data were analysed based on grounded theory. The final tool was revised at an expert stakeholder workshop. Results: Forty-three participants were interviewed within the semi-structured interview study, 32 participated in the questionnaire rounds and nine stakeholders attended the expert workshop. The final version of the POCKET checklist contains 65 different evidence requirements grouped into seven themes. Face validity, content validity and usability has been demonstrated. There exists a shortfall in the evidence that industry and research methodologists believe should be generated regarding POCTs and what is actually required by policy and decision makers to promote implementation into current healthcare pathways. Conclusions: This study has led to the development of POCKET, a checklist for evidence generation and synthesis in POCTs. This aims to guide industry and researchers to the evidence that is required by decision makers to facilitate POCT adoption so that the benefits they can bring to patients can be effectively realised. [ABSTRACT FROM AUTHOR]

Background: Measuring the glucose concentration in whole blood samples is critical due to unsatisfactory glycolysis inhibition. Previous studies showed that Terumo tubes were superior, but they were taken off the European market in 2016 and alternatives were required. This initiated the present evaluation of glucose stability in five available tube types. Methods: Venous blood samples were collected from 61 healthy volunteers to test tubes supplied by Terumo (two sets), Greiner FC-Mix, BD FX-Mixture and BD serum. After sampling, the contents were thoroughly mixed and centrifuged within an hour. The glucose concentrations were determined and the samples resuspended except for BD serum tubes (gel barrier). The first 30 samples were stored at room temperature and the remaining 31 at 4 °C. After 24, 48, 72 and 96 h, all tubes were (re)centrifuged, and glucose concentration measurements were repeated. Results: Changes in glucose concentrations over time differed significantly between the investigated tube types and to a certain extent between the two storing conditions. Glycolysis was most evident in the BD FX-mixture tubes. Good glucose stability was observed in samples retrieved form BD serum and Greiner tubes. The stability in both Terumo tubes was comparable to that in other studies. Although Greiner and both Terumo tubes are supposed to contain the same glycolysis inhibitor, glucose stability differed between these tubes. Conclusions: We showed that Greiner is an acceptable alternative to Terumo and that glucose in serum that was rapidly separated from corpuscles by a gel barrier is stable for an extended time. [ABSTRACT FROM AUTHOR]

Background: We verified the analytical performance of strip-based handheld glucose meters (GM) for prescription use, in a comparative split-sample protocol using blood gas samples from a surgical intensive care unit (ICU). Methods: Freestyle Precision Pro (Abbott), StatStrip Connectivity Meter (Nova), ACCU-CHEK Inform II (Roche) were evaluated for recovery/linearity, imprecision/repeatability. The GMs and the ABL90 (Radiometer) blood gas analyzer (BGA) were tested for relative accuracy vs. the comparator hexokinase glucose-6-phosphate-dehydrogenase (HK/G6PDH) assay on a Cobas c702 analyzer (Roche). Results: Recovery of spiked glucose was linear up to 19.3 mmol/L (347 mg/dL) with a slope of 0.91-0.94 for all GMs. Repeatability estimated by pooling duplicate measurements on samples below (n=9), in (n=51) or above (n=80) the 4.2-5.9 mM (74-106 mg/dL) range were for Freestyle Precision Pro: 4.2%, 4.0%, 3.6%; StatStrip Connectivity Meter: 4.0%, 4.3%, 4.5%; and ACCU-CHEK Inform II: 1.4%, 2.5%, 3.5%. GMs were in agreement with the comparator method. The BGA outperformed the GMs, with a MARD of 3.9% compared to 6.5%, 5.8% and 4.4% for the FreeStyle, StatStrip and ACCU-CHEK, respectively. Zero % of the BGA results deviated more than the FDA 10% criterion as compared to 9.4%, 3.7% and 2.2% for the FreeStyle, StatStrip and ACCU-CHEK, respectively. For all GMs, icodextrin did not interfere. Variation in the putative influence factors hematocrit and O2 tension could not explain observed differences with the comparator method. Conclusions: GMs quantified blood glucose in whole blood at about the 10% total error criterion, proposed by the FDA for prescription use. [ABSTRACT FROM AUTHOR]

Background: Blood glucose self-monitoring by individuals with diabetes is essential in controlling blood glucose levels. The International Organization for Standardization (ISO) introduced new standards for blood glucose monitoring systems (BGMS) in 2013 (ISO 15197: 2013). The CONTOUR PLUS® (CONTOUR PLUS) BGMS has been demonstrated to meet the 2013 ISO standards; however, no Chinese data on CONTOUR PLUS accuracy and precision have been published. Methods: This study evaluated the accuracy and precision of CONTOUR PLUS BGMS in quantitative glucose testing of capillary and venous whole blood samples obtained from 363 patients at three different hospitals. Results: Results of fingertip and venous blood glucose measurements by the CONTOUR PLUS system were compared with laboratory reference values to determine accuracy. Accuracy was 98.1% (96.06%-99.22%) for fingertip blood tests and 98.1% (96.02%-99.21%) for venous blood tests. Precision was evaluated across a wide range of blood glucose values (5.1-17.2 mmol/L), testing three blood samples repeatedly 15 times with the CONTOUR PLUS blood glucose meter using test strips from three lots. All within-lot results met ISO criteria (i.e., SD<0.42 mmol/L for blood glucose concentration <5.55 mmol/L; CV<7.5% for blood glucose concentration ≥5.55 mmol/L). Between-lot variations were 1.5% for low blood glucose concentration, 2.4% for normal and 3.4% for high. Conclusions: Accuracy of both fingertip and venous blood glucose measurements by the CONTOUR PLUS system was >95%, confirming that the system meets ISO 15197: 2013 requirements. [ABSTRACT FROM AUTHOR]

Background: Measurement uncertainty is a metrological concept to quantify the variability of measurement results. There are two approaches to estimate measurement uncertainty. In this study, we sought to provide practical and detailed examples of the two approaches and compare the bottom-up and top-down approaches to estimating measurement uncertainty. Methods: We estimated measurement uncertainty of the concentration of glucose according to CLSI EP29-A guideline. Two different approaches were used. First, we performed a bottom-up approach. We identified the sources of uncertainty and made an uncertainty budget and assessed the measurement functions. We determined the uncertainties of each element and combined them. Second, we performed a top-down approach using internal quality control (IQC) data for 6 months. Then, we estimated and corrected systematic bias using certified reference material of glucose (NIST SRM 965b). Results: The expanded uncertainties at the low glucose concentration (5.57 mmol/L) by the bottom-up approach and top-down approaches were ±0.18 mmol/L and ±0.17 mmol/L, respectively (all k=2). Those at the high glucose concentration (12.77 mmol/L) by the bottom-up and top-down approaches were ±0.34 mmol/L and ±0.36 mmol/L, respectively (all k=2). Conclusions: We presented practical and detailed examples for estimating measurement uncertainty by the two approaches. The uncertainties by the bottom-up approach were quite similar to those by the top-down approach. Thus, we demonstrated that the two approaches were approximately equivalent and interchangeable and concluded that clinical laboratories could determine measurement uncertainty by the simpler top-down approach. [ABSTRACT FROM AUTHOR]

The article presents abstracts on topics related to standardisation, accreditation and harmonisation of clinical tests including the development of enzymology reference system in China, mass spectrometry analysis of serum testosterone, and the determination of estimated plasma glucose level.

Background: Previous studies of participants with plasma glucose concentrations at or near the glucose reference range demonstrate glucose loss following delayed separation and extraction of plasma from the cellular components of blood, of ≤7% per hour. We aimed to assess pre-analytical glucose loss in diabetic subjects, focusing on the first hour after sample collection. Methods: Venous blood was collected from diabetes clinic attendees, into a series of lithium heparin PST™ (plasma separator tube) and fluoride oxalate Vacutainers™. Baseline (reference) plasma glucose measurements were undertaken on samples prepared under refrigerated conditions. The remaining samples underwent a series of controlled pre-analytical delays in sample preparation, at room temperature. Plasma glucose was measured using the hexokinase method. Results: Median baseline glucose (mmol/L) for the 62 participants was 10.6 (range 3.4-31.1). Using lithium heparin PST™ tubes, mean glucose loss (95% CI) was 0.16 (0.09-0.23) after 30 min delay in plasma preparation and 0.28 (0.21-0.34) after 60 min delay. Glucose loss was independent of both baseline glucose and also individual cellular count. Fluoride failed to inhibit glucose loss within the first hour after sample collection. Immediate plasma centrifugation of PST™ tubes, followed by delayed plasma extraction (median delay 92 min), produced a mean glucose loss of 0.02 mmol/L (-0.05-0.09). Conclusions: Samples collected into lithium heparin PST™ tubes show pre-analytical glucose loss at 1 h that is independent of baseline glucose and cellular count. Furthermore, immediate plasma separation using these tubes attenuates glucose loss across a wide range of glucose concentrations. [ABSTRACT FROM AUTHOR]

Background: Point-of-care (POC) glucose devices are widely used for insulin-dosage decision-making although such an application is not always permitted. In this study, we have evaluated a new generation of POC glucose device, the HemoCue® Glucose 201DMRT (201DMRT), for its suitability for (tight) glycemic control. Materials and methods: This study was performed according to the CLSI/STARD criteria. The 201DMRT was compared to the laboratory hexokinase glucose method (Siemens Dimension Vista®). The variation among different POC devices and cuvette lot numbers was examined. Additionally, the influence of the partial pressure of oxygen and hematocrit on glucose measurement was investigated. Results: The 201DMRT showed a good agreement with the laboratory reference method. This was examined using Deming regression analysis, percentage Bland-Altman plot and a modified Clarke-error grid. The total analytical error at the clinically critical glucose concentrations of 5.6, 7.0 and 11.1 mmol/L (101, 126 and 200 mg/dL) was 6.4%, 4.3% and 3.0%, respectively. The total error among the different POC devices and among different cuvette lot numbers was <6.5%. Glucose measurements on the 201DMRT were not affected by changes in partial pressure of oxygen, whereas changes in hematocrit had influence on the results (3.4% for every 0.10 L/L change in hematocrit). Conclusions: The 201DMRT device can be used for glycemic control based on analytical results presented. However, the clinical applicability for tight glycemic control must be confirmed in a clinical study. [ABSTRACT FROM AUTHOR]

The article describes the cases of two patients with a history of type 2 diabetes and signs of diabetic complications for whom hemoglobin A1c (HbA1c) measurement could not be obtained from testing. The fasting plasma glucose (FPG) levels of the patients were measured using the hexokinase method on the cobas 6000 analyzer. Results indicate that an immunoassay method can be an alternative method to determine HbA1c in hemoglobin Porto Alegre variant carriers.

The authors comment on a study published within the issue which confirms the effectiveness of citric acid as an immediate inhibitor of glycolysis and describes the effect of using citrate tubes on the rate of diabetes diagnosis. They discuss the limitations of using sodium fluoride (NaF) in inhibiting glycolysis, measuring blood glucose and detecting diabetes. They also recommend conducting additional studies on the effect of prompt inhibition of glycolysis on the diagnosis of diabetes.

A correction to the article "The Relationship Between Estimated Average Glucose and Fasting Plasma Glucose" which appeared in the 2013; 51(11) issue of the periodical is presented.