scholarly journals A method comparison study of a point-of-care blood gas analyser with a laboratory auto-analyser for the determination of potassium concentrations during hyperkalaemia in patients with kidney disease

2020 ◽  
Vol 30 (3) ◽  
pp. 432-438
Author(s):  
Mogamat-Yazied Chothia ◽  
Patricia Kassum ◽  
Annalise Zemlin
Keyword(s):  
Regression Analysis ◽  
Systematic Error ◽  
Potassium Concentration ◽  
Point Of Care ◽  
Venous Blood ◽  
Mean Difference ◽  
Renal Unit ◽  
Blood Gas ◽  
Altman Analysis ◽  
Bland Altman Analysis

Introduction: Hyperkalaemia is a common electrolyte disorder that may cause life-threatening cardiac arrythmias. We aimed to determine the agreement of potassium concentrations between GEM premier 3500 point-of-care blood gas analyser (POC-BGA) and Roche Cobas 6000 c501 autoanalyser in patients with hyperkalaemia. Methods: A prospective, cross-sectional study of all consecutive adult patients referred to the Renal Unit with a serum potassium concentration ≥ 5.5 mmol/L was performed. A total of 59 paired venous blood samples were included in the final statistical analysis. Passing-Bablok regression and Bland Altman analysis were used to compare the two methods. Results: The median laboratory auto-analyser potassium concentration was 6.1 (5.9-7.1) mmol/L as compared to the POC-BGA potassium concentration of 5.7 (5.5-6.8) mmol/L with a mean difference of - 0.43 mmol/L and 95% upper and lower limits of agreement of 0.35 mmol/L and - 1.21 mmol/L, respectively. Regression analysis revealed proportional systematic error. Test for linearity did not indicate significant deviation (P = 0.297). Conclusion: Although regression analysis indicated proportional systematic error, on Bland Altman analysis, the mean difference appeared to remain relatively constant across the potassium range that was evaluated. Therefore, in patients presenting to the emergency department with a clinical suspicion of hyperkalaemia, POC-BGA potassium concentrations may be considered a surrogate for laboratory auto-analyser measurements once clinicians have been cautioned about this difference.

scholarly journals Diagnosis of Gestational Diabetes Mellitus with Point-of-Care Methods for Glucose versus Hospital Laboratory Method Using Isotope Dilution Gas Chromatography-Mass Spectrometry as Reference

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Karl Kristensen ◽  
Anne-Marie Wangel ◽  
Anastasia Katsarou ◽  
Nael Shaat ◽  
David Simmons ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Gestational Diabetes ◽  
Gestational Diabetes Mellitus ◽  
Point Of Care ◽  
Gas Chromatography Mass Spectrometry ◽  
Positive Bias ◽  
Altman Analysis ◽  
Bland Altman Analysis

Background. In Sweden, both glucose analyzers in accredited laboratories and point-of-care glucose devices are used for gestational diabetes mellitus (GDM) diagnosis. The aim of this study was to compare the diagnostic performance of the HemoCue Glucose 201+ (HC201+) and RT (HC201RT) systems with that of the hospital central laboratory hexokinase method (CL) based on lyophilized citrate tubes, using the isotope dilution gas chromatography-mass spectrometry (ID GC-MS) as reference. Methods. A 75 g oral glucose tolerance test was performed on 135 women screened positive for GDM. Diagnosis was based on the World Health Organization 2013 diagnostic thresholds for fasting (n=135), 1 h (n=52), and 2 h (n=135) glucose measurements. Bland-Altman analysis and surveillance error grids were used to evaluate analytical and clinical accuracy. Results. Significantly more women were diagnosed with GDM by HC201+ (80%) and CL (80%) than with the reference (65%, P<0.001) based on fasting and/or 2 h thresholds, whereas the percentage diagnosed by HC201RT (60%) did not differ significantly from the reference. In Bland-Altman analysis, a positive bias was observed for HC201+ (4.2%) and CL (6.1%) and a negative bias for HC201RT (−1.8%). In the surveillance error grid, 95.9% of the HC201+ values were in the no-risk zone as compared to 98.1% for HC201RT and 97.5% for CL. Conclusions. A substantial positive bias was found for CL measurements resulting in overdiagnosis of GDM. Our findings suggest better performance of HC201RT than HC201+ in GDM diagnosis. The results may have possible implications for GDM diagnosis in Sweden and require further elucidation.

scholarly journals A paradigmatic case of haemolysis and pseudohyperkalemia in blood gas analysis

2018 ◽  
Vol 29 (1) ◽  
pp. 169-172
Author(s):  
Gian Luca Salvagno ◽  
Davide Demonte ◽  
Giuseppe Lippi
Keyword(s):  
Reference Range ◽  
Point Of Care ◽  
Venous Blood ◽  
Blood Gas Analysis ◽  
Plasma Potassium ◽  
Gas Analysis ◽  
Blood Gas ◽  
High Potassium ◽  
Plastic Tube ◽  
History Of

A 51-year old male patient was admitted to the hospital with acute dyspnea and history of chronic asthma. Venous blood was drawn into a 3.0 mL heparinized syringe and delivered to the laboratory for blood gas analysis (GEM Premier 4000, Instrumentation Laboratory), which revealed high potassium value (5.2 mmol/L; reference range on whole blood, 3.5-4.5 mmol/L). This result was unexpected, so that a second venous blood sample was immediately drawn by direct venipuncture into a 3.5 mL lithium-heparin blood tube, and delivered to the laboratory for repeating potassium testing on Cobas 8000 (Roche Diagnostics). The analysis revealed normal plasma potassium (4.6 mmol/L; reference range in plasma, 3.5-5.0 mmol/L) and haemolysis index (5; 0.05 g/L). Due to suspicion of spurious haemolysis, heparinized blood was transferred from syringe into a plastic tube and centrifuged. Potassium and haemolysis index were then measured in this heparinized plasma, confirming high haemolysis index (50; 0.5 g/L) and pseudohyperkalemia (5.5 mmol/L). Investigation of this case revealed that spurious haemolysis was attributable to syringe delivery in direct ice contact for ~15 min. This case emphasizes the importance of avoiding sample transportation in ice and the need of developing point of care analysers equipped with interference indices assessment.

scholarly journals Can the blood gas analyser results be believed? A prospective multicentre study comparing haemoglobin, sodium and potassium measurements by blood gas analysers and laboratory auto-analysers

2019 ◽  
Vol 47 (2) ◽  
pp. 120-127 ◽  
Author(s):  
Katherine E Triplett ◽  
Bradley A Wibrow ◽  
Richard Norman ◽  
Dana A Hince ◽  
Liesel E Hardy ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Point Of Care ◽  
Mean Difference ◽  
Full Blood Count ◽  
Blood Gas ◽  
Prospective Multicentre Study ◽  
Significant Difference ◽  
The Mean ◽  
Sodium And Potassium

Blood gas analysers are point-of-care testing devices used in the management of critically ill patients. Controversy remains over the agreement between the results obtained from blood gas analysers and laboratory auto-analysers for haematological and biochemistry parameters. We conducted a prospective analytical observational study in five intensive care units in Western Australia, in patients who had a full blood count (FBC), urea, electrolytes and creatinine (UEC), and a blood gas performed within 1 h of each other during the first 24 h of their intensive care unit admission. The main outcome measure was to determine the agreement in haemoglobin, sodium, and potassium results between laboratory haematology and biochemistry auto-analysers and blood gas analysers. A total of 219 paired tests were available for haemoglobin and sodium, and 215 for potassium. There was no statistically significant difference between the results of the blood gas and laboratory auto-analysers for haemoglobin (mean difference –0.35 g/L, 95% confidence interval (CI) –1.20 to 0.51, P = 0.425). Although the mean differences between the two methods were statistically significant for sodium (mean difference 1.49 mmol/L, 95% CI 1.23–1.76, P < 0.0001) and potassium (mean difference 0.19 mmol/L, 95% CI 0.15–0.24, P < 0.0001), the mean biases on the Bland–Altman plots were small and independent of the magnitude of the measurements. The two methods of measurement for haemoglobin, sodium and potassium agreed with each other under most clinical situations when their values were within or close to normal range suggesting that routine concurrent blood gas and formal laboratory testing for haemoglobin, sodium and potassium concentrations in the intensive care unit is unwarranted.

scholarly journals Performance of StatSensor Point-of-Care Device for Measuring Creatinine in Patients With Chronic Kidney Disease and Postkidney Transplantation

2020 ◽  
Vol 7 ◽  
pp. 205435812097071
Author(s):  
Melissa Nataatmadja ◽  
Angela W. S. Fung ◽  
Beryl Jacobson ◽  
Jack Ferera ◽  
Eva Bernstein ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Whole Blood ◽  
Point Of Care ◽  
Reference Method ◽  
Plasma Creatinine ◽  
Altman Analysis ◽  
Bland Altman Analysis ◽  
Deming Regression ◽  
Ckd Stage

Background: The StatSensor is a point-of-care device which measures creatinine in capillary whole blood. Previous studies reported an underestimation of the creatinine measurements at high creatinine concentrations and were performed in the prestandardization era for creatinine. Objective: This accuracy-based study evaluates the use of this device in kidney-transplanted patients and those with chronic kidney disease (CKD). Design: Cross-sectional diagnostic accuracy study. Setting: Nephrology outpatient clinic in an urban tertiary center. Participants: Adults with CKD or a functioning kidney transplant. Measurements: Duplicate StatSensor creatinine measurements were performed on capillary whole blood samples collected by direct fingerstick and SAFE-T-FILL collection device. Results were compared with simultaneous venous blood sampling for serum and plasma creatinine measured by an enzymatic method on the Roche Integra 400 mainframe analyzer with traceability to the ID-GC-MS (isotope dilution gas chromatography mass spectrometry) reference method. Methods: Deming regression, Pearson correlation coefficient, and Bland-Altman analysis were used to assess accuracy and comparability between capillary whole blood measured by StatSensor and plasma creatinine measured by routine analyzer with traceability to the reference method. Estimated glomerular filtration (eGFR) rates were calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and concordance with Kidney Disease Improving Global Outcomes (KDIGO) CKD stage classification was evaluated. Results: There were 60 participants (mean age = 61.9 ± 15.0 years, 55% men, 33% transplant, mean plasma creatinine = 137 ± 59 µmol/L). Bland-Altman analysis indicated a positive mean bias of 12.7 µmol/L between StatSensor fingerstick creatinine measurement and plasma creatinine. Comparison of eGFR (CKD-EPI) calculated from the StatSensor fingerstick creatinine versus plasma creatinine showed misclassification across all KDIGO CKD stages. Postanalytical correction of the bias did not improve misclassifications. The use of mean of duplicate StatSensor creatinine results did not improve performance compared with the use of singlet results. Limitations: Single center, limited participant numbers. Conclusions: The results of our study suggest that the limiting characteristics of the StatSensor device are not only bias, but also imprecision. The level of imprecision observed may influence clinical decision-making and limit the usefulness of StatSensor as a CKD screening tool. If choosing to utilize it for either screening for or monitoring CKD, it is essential that clinicians understand the limitations of point-of-care devices and apply this knowledge to test interpretation.

scholarly journals Comparison of activated clotting times measured using the Hemochron Jr. Signature and Medtronic ACT Plus during cardiopulmonary bypass with acute normovolemic haemodilution

2017 ◽  
Vol 46 (2) ◽  
pp. 873-882 ◽  
Author(s):  
Jung Min Lee ◽  
Eun Young Park ◽  
Kyung Mi Kim ◽  
Jong Chan Won ◽  
Tack Koon Jung ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
Bolus Dose ◽  
Blood Glucose Concentration ◽  
Altman Analysis ◽  
Clotting Time ◽  
Bland Altman Analysis ◽  
Activated Clotting Time ◽  
Protamine Administration

Objective This study compared the activated clotting time (ACT) measured using the Hemochron Jr. Signature (HACT) with the ACT measured using the Medtronic ACT Plus (MACT) during cardiopulmonary bypass (CPB) with acute normovolemic haemodilution (ANH) in patients undergoing cardiac surgery. Methods The ACT was checked at baseline with both devices after inducing anaesthesia, and 400 to 800 mL of whole blood was withdrawn to induce moderate ANH. Before initiating CPB, a 300-IU/kg bolus dose of heparin was administered to maintain the HACT at >400 s; protamine was later given to reverse the anticoagulation. The ACT was checked using both devices at baseline, during heparinisation, and after protamine administration. Results In total, 106 pairs of samples from 29 patients were analysed. The ACT showed a good correlation between the two devices (r = 0.956). However, Bland–Altman analysis showed that the MACT was higher, particularly at baseline and during heparinisation. Multiple regression analysis showed that the blood glucose concentration significantly influenced the differences between the two ACT devices. Conclusions The HACT was lower than the MACT during CPB with ANH in patients undergoing cardiac surgery. Clinicians should be cautious when using each ACT device within generally accepted reference ACT values.

scholarly journals Multicenter comparison of the Cobas 6800 system with the RealStar RT-PCR kit for the detection of SARS-CoV-2

2020 ◽  
Author(s):  
Marc Wirden ◽  
Linda Feghoul ◽  
Mélanie Bertine ◽  
Marie-Laure Nere ◽  
Quentin Le Hingrat ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Linear Regression Analysis ◽  
Regression Line ◽  
Clinical Samples ◽  
Altman Analysis ◽  
Rt Pcr ◽  
Bland Altman Analysis ◽  
Deming Regression ◽  
The Mean ◽  
Pcr Assays

ABSTRACTBackgroundRT-PCR testing is crucial in the diagnostic of SARS-CoV-2 infection. The use of reliable and comparable PCR assays is a cornerstone to allow use of different PCR assays depending on the local equipment. In this work, we provide a comparison of the Cobas® (Roche) and the RealStar® assay (Altona).MethodsAssessment of the two assays was performed prospectively in three reference Parisians hospitals, using 170 clinical samples. They were tested with the Cobas® assay, selected to obtain a distribution of cycle threshold (Ct) as large as possible, and tested with the RealStar assay with three largely available extraction platforms: QIAsymphony (Qiagen), MagNAPure (Roche) and NucliSENS-easyMag (BioMérieux).ResultsOverall, the agreement (positive for at least one gene) was 76%. This rate differed considerably depending on the Cobas Ct values for gene E: below 35 (n = 91), the concordance was 99%. Regarding the positive Ct values, linear regression analysis showed a determination correlation (R2) of 0.88 and the Deming regression line revealed a strong correlation with a slope of 1.023 and an intercept of -3.9. Bland-Altman analysis showed that the mean difference (Cobas® minus RealStar®) was + 3.3 Ct, with a SD of + 2.3 Ct.ConclusionsIn this comparison, both RealStar® and Cobas® assays provided comparable qualitative results and a high correlation when both tests were positive. Discrepancies exist after 35 Ct and varied depending on the extraction system used for the RealStar® assay, probably due to a low viral load close to the detection limit of both assays.

scholarly journals The TRUTH confirmed: validation of an intraindividual comparison of gadobutrol and gadoteridol for imaging of glioblastoma using quantitative enhancement analysis

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Matthew J. Kuhn ◽  
Julia W. Patriarche ◽  
Douglas Patriarche ◽  
Miles A. Kirchin ◽  
Massimo Bona ◽  
...  
Keyword(s):  
Pearson Correlation ◽  
Linear Regression Analysis ◽  
Region Of Interest ◽  
Mean Difference ◽  
Altman Analysis ◽  
Double Blind ◽  
Bland Altman Analysis ◽  
Intraindividual Comparison ◽  
Contrast Enhanced ◽  
Magnetic Resonance Imaging Mri

Abstract Background Previous intraindividual comparative studies evaluating gadobutrol and gadoteridol for contrast-enhanced magnetic resonance imaging (MRI) of brain tumours have relied on subjective image assessment, potentially leading to misleading conclusions. We used artificial intelligence algorithms to objectively compare the enhancement achieved with these contrast agents in glioblastoma patients. Methods Twenty-seven patients from a prior study who received identical doses of 0.1 mmol/kg gadobutrol and gadoteridol (with appropriate washout in between) were evaluated. Quantitative enhancement (QE) maps of the normalised enhancement of voxels, derived from computations based on the comparison of contrast-enhanced T1-weighted images relative to the harmonised intensity on unenhanced T1-weighted images, were compared. Bland-Altman analysis, linear regression analysis and Pearson correlation coefficient (r) determination were performed to compare net QE and per-region of interest (per-ROI) average QE (net QE divided by the number of voxels). Results No significant differences were observed for comparisons performed on net QE (mean difference -24.37 ± 620.8, p = 0.840, r = 0.989) or per-ROI average QE (0.0043 ± 0.0218, p = 0.313, r = 0.958). Bland-Altman analysis revealed better per-ROI average QE for gadoteridol-enhanced MRI in 19/27 (70.4%) patients although the mean difference (0.0043) was close to zero indicating high concordance and the absence of fixed bias. Conclusions The enhancement of glioblastoma achieved with gadoteridol and gadobutrol at 0.1 mmol/kg bodyweight is similar indicating that these agents have similar contrast efficacy and can be used interchangeably, confirming the results of a prior double-blind, randomised, intraindividual, crossover study.

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