1,720,969 research outputs found
Mindray BS-800M1: a new clinical chemistry system with a flexible technology meeting quality performances.
No full textNew biochemical markers: from bench to bedside
No full textBackground: Evaluation of patients presenting to hospital with chest pain or other signs or symptoms suggesting acute coronary syndrome (ACS) is problematic, time-consuming and sometimes expensive, even if new biochemical markers, such as troponins, have improved the ability to detect cardiac injury. However, patients with normal troponin values are not necessarily risk-free for major cardiac events.
Methods: Recent investigations indicate that the overall patient risk may be assessed earlier than before, thanks to new knowledge acquired concerning the pathobiology of atherosclerosis and molecular events involved in the progression of disease, thus allowing the development of new biochemical markers. Some selected markers are released during the different phases of development of cardiovascular disease and may be useful for the diagnosis of patients with cardiovascular disease. In particular, the identification of emerging markers that provide relevant information on the inflammatory process, and the development of biomarkers whose circulating concentrations suggest the status of plaque instability and rupture, seems to be of particular value in prognosis and risk stratification. The overall expectations for a cardiovascular biochemical marker are not only its biological plausibility but also the availability at a reasonable cost of rapid, high quality assays, and their correct interpretation by clinicians using optimal cut-offs.
Conclusion: The crossing from bench to bedside for each new marker discovered, must be associated with concurrent advances in the characterization of analytical features and the development of routine assay, in the assessment of analytical performance and in interpretative reporting of test results as well as in the training of physicians to use the array of biomarkers available appropriately and to interpret them correctly. This approach calls for the coordinated support of clinicians, technology experts, statisticians and the industry so that new biochemical developments can be of optimal value. (c) 2007 Elsevier B.V. All rights reserved
Innotrac Aio! a point-of-care or a routine analyzer? Analytical performance and plasma/whole blood comparison
No full textBackground and methods: The aim of the present study was to evaluate the analytical performance of the Innotrac Aio! analyzer in measuring the cardiac markers troponin I (Tnl), myoglobin (Myo) and creatine kinase-MB (CK-MB), both in lithium heparin plasma and in whole blood.
Results: TnI analytical sensitivity was 0.012 mu g/L and the concentration corresponding to CV=10% was 0.036 mu g/L. In healthy subjects, the 99th percentile TnI values were 0.023 and 0.016 mu g/L in whole blood and in plasma, respectively. One hundred samples were tested both in whole blood and in plasma: Tnl-whole-bloods=1.16-plasmaq+0.011, bias=0.18 (95% CI from -0.22 to +0.59); Myo-whole-blood=1.04-plasma -1.93, bias=+1.08 (95% CI from -6.17 to +8.32); CK-MB-whole-blood=1.11-plasma -0.09, bias=+0.96 (95% CI from -0.53 to +2.45). The method comparison with the RxL Dimension analyzer for TnI and Myo gave the following results: TnI AioI =0.30 TnI RxL + 0.00; bias=-5.80 (95% CI from -7.81 to -3.78), Myo Aio! =1.33 Myo RxL + 0.42, bias=+53.09 (95% CI from +38.44 to +67.74).
Conclusions: The analytical performance of the Innotrac Aio! analyzer was satisfactory for all three cardiac markers evaluated and, in particular, the TnI method provided sensitive and accurate results. The most important finding in this study is the possibility to perform the tests as either routine or point-of-care analysis, thus overcoming the variability of results obtained employing different methods
PATHFAST NT-proBNP (N-terminal-pro B type natriuretic peptide): a multicenter evaluation of a new point-of-care assay.
No full textPerformance characteristics of laboratory testing and clinical outcomes.
No full textIn order to demonstrate the relationship between performance characteristics of laboratory tests and clinical outcomes, diabetes seems to represent a paradigmatic disease: diagnosis, monitoring of therapeutic efficacy and prognosis are adequately achieved by means of laboratory testing. Starting from a simple molecule, glucose, used for the diagnosis of diabetes, continuing with creatinine, used for monitoring renal function in diabetic patients and concluding with cardiac troponins, a recognised gold standard for the diagnosis and risk stratification of cardiovascular diseases, several criticisms may be stressed considering the current methodological state-of-the art. Finally, an often overlooked aspect of performance, the analytical interferences, being responsible of unexpected results, that in turn depend from unknown or undisclosed factors will be discussed. concerning in particular, in our paper, the macroprolactin and the heterophilic antibodies aspects. (c) 2009 Elsevier B.V. All rights reserved
Analytical and clinical performance of a fully automated cardiac multi-markers strategy based on protein biochip microarray technology.
No full textObjectives: The analytical and clinical performance of the Evidence (R) Cardiac Panel were evaluated.
Design and methods: The Evidence (R) Cardiac Panel, an automated protein biochip microarray system, allows the simultaneous determination of creatine kinase MB (CK-MB), myoglobin (MYO), glycogen phosphorylase 1313 (GPBB), heart-type fatty acid-binding protein (H-FABP), carbonic anhydrase III (CA III), cardiac troponin I (cTnI). Precision: 3 levels of quality control (QQ and 2 in house pools (P) were assayed.
Method comparison: MYO and cTnI concentrations measured on Evidence (R) (E) and on Dimension (R) RxL (D) analyzers were compared. Clinical study: 132 non-consecutive patients admitted to the Emergency Department for chest pain were enrolled.
Results and conclusions: The between-day imprecision was CK-MB=6.80-10.08%; MYO=5.36-16.50%; GPBB=6.51-12.12%; H-FABP=6.26-12.63%; CA III=6.98-13.61%; cTnI=6.02-9.80%. Method comparison: E-MYO vs. D-MYO, Bias=-29.22, 95% CI from -40.25 to - 18.18; E-cTnI vs. D-cTnI, Bias=-2.75, 95% CI from -4.04 to - 1.46. In patients studied (at discharge: AMI, acute myocardial infarction n=42; non-AMI, n=90) H-FABP showed the highest accuracy (ROC analysis, AUC=0.92) and "cTnl+H-FABP" the greatest diagnostic efficacy (89.4%) in AMI diagnosis. (C) 2007 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved
Effect of a dialysis session on the prognostic values of NT-proBNP, troponins, endothelial damage and inflammation biomarkers
No full textAbstract
BACKGROUND: In hemodialysis, the relationship between the increased concentration of natriuretic peptides and volume overload, inflammatory activity, endothelial dysfunction, left ventricular function and mass, and silent ischemic events is not clear. To investigate the relationship, a 3-year prospective cohort study was conducted in 50 adult hemodialysis patients in NYHA class I-II who were free from diabetes and ischemic heart events.
METHODS: Doppler echocardiogram, plasma NT-proBNP, troponin T and I, CRP, TNF alpha, big-endothelin 1, and cystatin-C, were determined both before and after a dialysis session. The outcome was all-cause death.
RESULTS: 13 out of 50 patients died. Survival curves significantly differed by age (above vs. below the median 68 yrs), NT-proBNP (9719 pg/mL), troponin T (0.03 ng/mL), C-reactive protein (4.8 mg/L), left atrial volume index (51 mL/sqm), ejection fraction (61%), and diastolic pattern. In the Cox model only NT-proBNP (cutoff 10000 pg/mL) had a significant hazard ratio (4.1). Post-HD measurements of NT-proBNP, troponin T, and CRP maintained their prognostic value. The high correlation between pre and post values of NT-proBNP, and the lack of correlation with ultrafiltration volume excluded a role for acute fluid removal on its regulation.
CONCLUSIONS: The increased level of NT-proBNP is the most important prognostic factor even in the absence of severe heart dysfunction and myocardial ischemic events, without any relationship with endothelial dysfunction, inflammatory biomarkers, or with acute fluid removal. A cutoff value of NT-proBNP of 10000 pg/mL could be used to identify hemodialysis patients with a higher risk of death
Creatine-kinase MB mass: age and sex-associated reference limits in two different platforms that use the same method.
No full textBackground: Recent updated NACB guidelines suggest that troponins are the biomarker of choice for the detection of myocardial necrosis, but the CK-MB mass is still considered an effective and alternative indicator when troponin assays are not available. The aim of the present study was to compare the reliability of two different analytical platforms in establishing the gender-specific 99th percentile for the CK-MB mass.
Methods: Serum samples collected from healthy subjects were investigated in two different laboratories, LAB 1 (354 subjects: 222 men, 132 women; median age,40 years, range 19-64 years) and LAB 2 (330 subjects: 224 men, 106 women; median age, 41 years, range 18-71 years), in order to determine the CK-MB mass (mu g/L) using the Access (R) CKMB (R) method (Beckman Coulter), a two-site immunoenzymatic sandwich assay, on UniCel (R) DxI 800 (LAB 1) and Access (R) 2 (LAB 2) analyzers (Beckman Coulter). The related plasma samples (lithium-heparin) were also evaluated in LAB 2.
Results: Total imprecision (CV%), calculated in control materials, ranged from 6.00 to 9.05 (concentration range, 3.82-36.37) in LAB I and from 7.05 to 5.02 in LAB 2 (concentration range, 3.63-34.18). A statistically significant gender-related difference (p < 0.05) was found in the whole population studied, values in men being higher than those in women: median=1.86 vs 1.22; 99th percentile=7.64 vs 5.19. The median values in subjects aged 18-28 years (group 1) were lower than those in the other 4 groups (2-5):1.12 vs 1.59, vs 1.78, vs 1.95 and vs 2.03. The same age-related trend was also observed for CK-MB plasma values, which were comparable to those observed in the matched-serum samples: median 1.12 vs 1.10 (group 1), 1.45 vs 1.50, (group 5).
Conclusions: The two different analytical platforms provide comparable results. The finding that CK-MB mass values are significantly higher in males than in females represents a relevant information, that will impact on patient classification when a myocardial necrosis has been suspected. Actually, however, numerous assays commercially available, lack of this information. (C) 2008 Published by Elsevier B.V
Effect of a last generation cardiac troponin assay on patients' management: a real world emergency department experience.
No full textShort Communication: Precision performance at low levels and 99th percentile concentration of the Access((R)) AccuTnI((R)) assay on two different platforms.
No full textBackground: Cardiac troponins currently represent the preferred biomarkers for the detection of myocardial necrosis. The objective of the present study was to compare the performance of the Access® AccuTnI ® assay (Beckman Coulter) measured on two different platforms, the UniCel® DxI 800 and the Access® 2 (Beckman Coulter). In particular, the serum cardiac troponin I (cTnI) concentration corresponding to 10% coefficient of variation (CV), the cTnI assay minimum detectable concentration (MDC), and the serum cTnI 99th percentile in healthy subjects were calculated. Methods: The Access® AccuTnI ® is a paramagnetic particle chemiluminescent immunoassay. Imprecision profiles were determined according to the Clinical and Laboratory Standards Institute EP5-A protocol using serum pools. The MDC was calculated as mean+3 SD of 20 determinations of the zero calibrator during one run. The 99th percentile was determined analyzing serum samples from 679 healthy blood donors (523 males, 156 females; 18-71 years old). Results: cTnI concentrations are given in μg/L. 10% CV values (95% confidence interval, CI) were 0.0577 (0.0467-0.0750) (UniCel® DxI 800) and 0.0486 (0.0255-0.0596) (Access® 2). MDC values were 0.011 (UniCel® DxI 800) and 0.012 (Access® 2). The 99th percentile (95% CI) value was 0.0340 (0.0298-0.0410). Conclusions: Our data confirm the reliability of the evaluated cTnI assay and demonstrate the comparability of the cTnI values between the platforms studied. © 2009 by Walter de Gruyter Berlin New York
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