BACKGROUND: Commutable reference materials (RMs) are suitable for end-users for evaluating the metrological traceability of values obtained using routine measurement systems. We assessed the performance of 6 routine measurement systems with validated secondary RMs. METHODS: We tested the homogeneity, stability, and commutability of 5 minimally processed human serum pools according to the standard guidelines. The serum pools were assigned values as per the reference procedure of the United States Centers for Disease Control and were used to evaluate the trueness of results from 6 commercial measurement systems based on enzymatic methods: 3 glucose oxidase (GOD) and 3 hexokinase (HK) methods. RESULTS: The prepared RMs were validated to be sufficiently homogenous, stable, and commutable with the patient samples. Method bias varied for different systems: GOD01, -0.17 to 2.88%; GOD02, 1.66 to 4.58%; GOD03, -0.17 to 3.14%; HK01, -3.48 to -0.85%; HK02, -3.83 to -0.11%, and HK03, -1.82 to -0.27%. CONCLUSIONS: We observed that the prepared serum glucose RMs were qualified for trueness assessment. Most of the measurement systems met the minimal quality specifications.
Blood Chemical Analysis/instrumentation/*standards ; Blood Glucose/*analysis ; Glucose Oxidase/metabolism ; Hexokinase/metabolism ; Humans ; Reagent Kits, Diagnostic ; Reference Standards ; Regression Analysis

BACKGROUND/AIMS: The application of glycated hemoglobin (HbA1c) for the diagnosis of diabetes is currently under extensive discussion. In this study, we explored the validity of using HbA1c as a screening and diagnostic test in Chinese subjects recruited in Nanjing, China. METHODS: In total, 497 subjects (361 men and 136 women) with fasting plasma glucose (PG) > or = 5.6 mmol/L were recruited to undergo the oral glucose tolerance test (OGTT) and HbA1c test. Plasma lipid, uric acid, and blood pressure were also measured. RESULTS: Using a receiver operating characteristic curve, the optimal cutoff point of HbA1c related to diabetes diagnosed by the OGTT was 6.3%, with a sensitivity and specificity of 79.6% and 82.2%, respectively, and the area under the curve was 0.87 (95% confidence interval, 0.83 to 0.92). A HbA1c level of 6.5% had a sensitivity and specificity of 62.7% and 93.5%, respectively. When comparing the HbA1c > or = 6.5% or OGTT methods for diagnosing diabetes, the former group had significantly higher HbA1c levels and lower levels of fasting and 2-hour PG than the latter group. No significant difference was observed in the other metabolism indexes between the two groups. CONCLUSIONS: Our results suggest that HbA1c > or = 6.5% has reasonably good specificity for diagnosing diabetes in Chinese subjects, which is in concordance with the American Diabetes Association recommendations.
Aged ; Analysis of Variance ; *Asian Continental Ancestry Group ; Biological Markers/blood ; Blood Glucose/analysis ; China/epidemiology ; *Chromatography, High Pressure Liquid/standards ; *Chromatography, Ion Exchange/standards ; Diabetes Mellitus, Type 2/blood/*diagnosis/ethnology ; Fasting/blood ; Female ; Glucose Tolerance Test/standards ; Hemoglobin A, Glycosylated/*analysis ; Humans ; Male ; Mass Screening/*methods/standards ; Middle Aged ; Predictive Value of Tests ; ROC Curve ; Reference Standards ; Reproducibility of Results ; Sensitivity and Specificity

PURPOSE: The purpose of this study was to investigate the effectiveness of an educational intervention that used both cellular phones and the Internet to provide a short messaging service (SMS) relating to blood glucose, blood pressure, and serum lipid levels in postmenopausal women with impaired fasting glucose (IFG). METHODS: Twenty-eight postmenopausal women were assigned to an intervention group and twenty-one postmenopausal women to a control group. The intervention was provided for 12 weeks. Patients in the intervention group were asked to access a web site by using a cellular phone or to use the Internet directly and input their blood glucose and blood pressure levels weekly. Participants were sent the optimal recommendations weekly by both cellular phone and Internet. RESULTS: The intervention group had a mean decrease in systolic blood pressure (SBP) level of 8.1 mmHg but changes for the control group were not significant. There was a significant mean change in diastolic blood pressure (DBP) level for the intervention group (-7.7 mmHg). The mean change in the control group was not significant. CONCLUSION: This educational intervention using the Internet and a SMS by cellular phone improved levels of SBP and DBP in postmenopausal women with IFG.
Blood Glucose/*analysis ; *Blood Pressure ; *Cellular Phone ; Diabetes Mellitus, Type 2/blood ; Fasting ; Female ; *Health Education/methods/standards ; Humans ; *Internet ; Interviews as Topic ; Lipids/blood ; Middle Aged ; *Postmenopause ; Program Evaluation

BACKGROUND: Measurement uncertainty characterizes the dispersion of the quantity values attributed to a measurand. Although this concept was introduced to medical laboratories some years ago, not all medical researchers are familiar with it. Therefore, the evaluation and expression of measurement uncertainty must be highlighted using a practical example. METHODS: In accordance with the procedure for evaluating and expressing uncertainty, provided by the Joint Committee for Guides in Metrology (JCGM), we used plasma glucose (Glu) as an example and defined it as the measurand. We then analyzed the main sources of uncertainty, evaluated each component of uncertainty, and calculated the combined uncertainty and expanded uncertainty with 2 budgets for single measurements and continuous monitoring, respectively. RESULTS: During the measurement of Glu, the main sources of uncertainty included imprecision, within-subject biological variance (BVw), calibrator uncertainty, and systematic bias. We evaluated the uncertainty of each component to be 1.26%, 1.91%, 5.70%, 0.42%, and -2.87% for within-run imprecision, between-day imprecision, BVw, calibrator uncertainty, and systematic bias, respectively. For a single specimen, the expanded uncertainty was 7.38% or 6.1+/-0.45 mmol/L (kappa=2); in continuous monitoring of Glu, the expanded uncertainty was 13.58% or 6.1+/-0.83 mmol/L (kappa=2). CONCLUSIONS: We have demonstrated the overall procedure for evaluating and reporting uncertainty with 2 different budgets. The uncertainty is not only related to the medical laboratory in which the measurement is undertaken, but is also associated with the calibrator uncertainty and the biological variation of the subject. Therefore, it is helpful in explaining the accuracy of test results.
Blood Chemical Analysis/methods/standards ; Clinical Chemistry Tests/*methods/standards ; Glucose/*analysis/standards ; Humans ; Models, Statistical ; Quality Control ; *Uncertainty

BACKGROUND: Measurement uncertainty characterizes the dispersion of the quantity values attributed to a measurand. Although this concept was introduced to medical laboratories some years ago, not all medical researchers are familiar with it. Therefore, the evaluation and expression of measurement uncertainty must be highlighted using a practical example. METHODS: In accordance with the procedure for evaluating and expressing uncertainty, provided by the Joint Committee for Guides in Metrology (JCGM), we used plasma glucose (Glu) as an example and defined it as the measurand. We then analyzed the main sources of uncertainty, evaluated each component of uncertainty, and calculated the combined uncertainty and expanded uncertainty with 2 budgets for single measurements and continuous monitoring, respectively. RESULTS: During the measurement of Glu, the main sources of uncertainty included imprecision, within-subject biological variance (BVw), calibrator uncertainty, and systematic bias. We evaluated the uncertainty of each component to be 1.26%, 1.91%, 5.70%, 0.42%, and -2.87% for within-run imprecision, between-day imprecision, BVw, calibrator uncertainty, and systematic bias, respectively. For a single specimen, the expanded uncertainty was 7.38% or 6.1+/-0.45 mmol/L (kappa=2); in continuous monitoring of Glu, the expanded uncertainty was 13.58% or 6.1+/-0.83 mmol/L (kappa=2). CONCLUSIONS: We have demonstrated the overall procedure for evaluating and reporting uncertainty with 2 different budgets. The uncertainty is not only related to the medical laboratory in which the measurement is undertaken, but is also associated with the calibrator uncertainty and the biological variation of the subject. Therefore, it is helpful in explaining the accuracy of test results.
Blood Chemical Analysis/methods/standards ; Clinical Chemistry Tests/*methods/standards ; Glucose/*analysis/standards ; Humans ; Models, Statistical ; Quality Control ; *Uncertainty

Blood Glucose ; analysis ; Capillaries ; metabolism ; Humans ; Hypoglycemia ; diagnosis ; Infant, Newborn ; Neonatal Screening ; methods ; Reference Standards

Age Factors ; Alanine Transaminase ; blood ; Blood Glucose ; analysis ; Body Mass Index ; Chemistry, Clinical ; standards ; Female ; Hepatitis B, Chronic ; blood ; pathology ; Hepatitis C, Chronic ; blood ; pathology ; Humans ; Lipids ; blood ; Liver Diseases ; blood ; pathology ; Male ; RNA, Viral ; blood ; Reference Values ; Retrospective Studies ; Sex Factors

BACKGROUND: We have evaluated the analytical performance of SureStep Flexx (Johnson and Johnson, USA) which can report the plasma equivalent glucose test results and be connected to the hospital information networks, following ISO15197 analytic procedure for glucometer for the first time. METHODS: Adopting the guidelines of ISO15197, we measured the precision of ten glucometers from their repeatability and intermediate precision, and determined the accuracies of the glucometer, comparing to those of GEM Premier 4000 (Instrumentation Laboratory, USA). In addition, the guidelines of CLSI EP9-A2 and EP6-A were applied to correlate between data of glucometer and those of laboratory reference method by TBA-200FR (Toshiba Medical Systems, Japan) and to examine its linearity of glucose concentrations measured by SureStep Flexx. We used the clinical specimens and commercial control materials. RESULTS: Repeatabilities and intermediate precisions of those glucometers were 4.0-7.3%, and 4.3-6.2%, respectively. When glucose levels are under 75 mg/dL, the difference between results of those meters and the reference values were within +/-6 mg/dL. However when glucose levels are over 75 mg/dL, those differences were within +/-12.7%. These results were acceptable for the ISO15197 criteria in all glucose concentrations. The glucose concentrations showed the clinically relevant linearity in the range from 36 mg/dL to 491 mg/dL. Moreover, Error Grid Analysis showed that all glucose results were in "zone A", which means that these values were clinically accurate. CONCLUSIONS: This study showed that SureStep Flexx can provide reliable results for patients and clinicians to manage the diabetes mellitus, satisfying the ISO15197 criteria.
Blood Glucose/*analysis ; Blood Glucose Self-Monitoring/*instrumentation/methods/*standards ; Diabetes Mellitus/blood/diagnosis ; Humans ; Quality Control ; Reference Values ; Reproducibility of Results

BACKGROUND: Point-of-care (POC) tests are used increasingly due to fast results and simple test procedures, which enables rapid diagnosis and therapeutic monitoring. We evaluated the performance of the Piccolo xpress Chemistry Analyzer (Abaxis, USA) a POC chemistry analyzer. METHODS: Fourteen analytes, Na+, K+, Cl-, Ca2+, total carbon dioxide, AST, ALT, total bilirubin, alkaline phosphatase, blood urea nitrogen, creatinine, albumin, total protein, and glucose; were measured simultaneously with a 100 microliter of whole blood sample using a Comprehensive Metabolic Reagent disk. Within-run and total precision and linearity were evaluated according to CLSI EP15-A and EP6-A guidelines, respectively. Comparison with a central laboratory chemistry analyzer was performed using 144 patient samples. RESULTS: The coefficients of variations of within-run and total precision were all within 5% for three levels except for total carbon dioxide, ALT, alkaline phosphatase, total bilirubin, and creatinine in low level, and creatinine in middle level. The results of 14 analytes were linear within a commonly encountered range in clinical samples (r2> or =0.98). More than 10% of samples in Na+, AST, ALT, glucose, BUN did not satisfy CLIA analytical quality requirement. CONCLUSIONS: The Piccolo xpress Chemistry Analyzer can analyze multiple analytes with a minimal amount of whole blood in a short time. It showed an acceptable performance for precision, linearity and comparison with central laboratory analyzer. It can be useful as a screening tests modality in mobile clinics, ambulances, and field clinics for military use, and for pediatric patients from whom enough sample volume is difficult to obtain.
Alanine Transaminase/blood ; Alkaline Phosphatase/blood ; Aspartate Aminotransferases/blood ; Bilirubin/blood ; Blood Chemical Analysis/*instrumentation/methods/*standards ; Blood Glucose/analysis ; Calcium/blood ; Carbon Dioxide/blood ; Chlorides/blood ; Creatinine/blood ; Humans ; *Point-of-Care Systems ; Potassium/blood ; Quality Control ; Reproducibility of Results ; Serum Albumin/analysis ; Sodium/blood

BACKGROUND: This study aimed to analyze the influence of the interruption of agitation and removal of leukocytes on platelet concentrates (PCs), and determine the maximum amount of time the agitation could be interrupted without impairing PCs' effectiveness during the storage period. METHODS: Four ABO-identical random donor platelets agitated for 24 hr were pooled, and divided into 4 units, and 2 units of them were leukoreduced. Then 52 pooled units were categorized into 4 groups, non-leukoreduced continuous agitation (Non-LRCA), non-leukoreduced interrupted agitation (Non-LRIA), leukoreduced continuous agitation (LRCA), and leukoreduced interrupted agitation (LRIA), and preserved for 6 days (total 7 days). Mean platelet volume (MPV), pH, HCO3-, pO2, pCO2, CD62P, CD61, glucose, lactate, ammonia and free fatty acid were measured during the period. RESULTS: Starting from the Day 4, the pH and HCO3- of Non-LRIA group begun to decrease while the amount of lactate production, glucose consumption, and MPV increased compared to the Non- LRCA group (P<0.01). An increase in pO2 level was observed in the interrupted agitation groups as the storage period prolonged (P<0.01). The pH levels of all the units in the agitation groups remained higher than 6.4 up to Day 7, while those of the non-leukoreduction group did so only up to Day 2, but those of leukoreduction in the interrupted agitation groups did so up to Day 4. CONCLUSIONS: The interruption of agitation reduced the platelet's capacity to utilize oxygen, increasing lactate amount and reducing pH level. However, the in vitro parameters of the Non-LRIA and Non-LRCA groups on Day 2 were similar to each other and the pH level remained at 6.4 or higher, making one day of agitation interruption possible after 24 hr of agitation. With leukocytes removed, the effective agitation interruption period may become longer.
*Blood Component Removal ; Blood Platelets/*cytology ; Blood Preservation/*standards ; Cell Separation ; Glucose/analysis ; Humans ; Hydrogen-Ion Concentration ; Lactic Acid/blood ; Oximetry ; P-Selectin/blood ; Time Factors ; Vibration