Cardiac troponin I elevation in acute pulmonary embolism is associated with right ventricular dysfunction

AbstractOBJECTIVESThe purpose of this study was to evaluate the prevalence and diagnostic utility of cardiac troponin I to identify patients with right ventricular (RV) dysfunction in pulmonary embolism.BACKGROUNDRight ventricular overload resulting from elevated pulmonary resistance is a common finding in major pulmonary embolism. However, biochemical markers to assess the degree of RV dysfunction have not been evaluated so far.METHODSIn this prospective, double-blind study we included 36 study patients diagnosed as having acute pulmonary embolism.RESULTSAmong the whole study population, 14 patients (39%) had positive troponin I tests. Ten of 16 patients (62.5%) with RV dilatation had increased serum troponin I levels, while only 4 of 14 patients (28.6%) with elevated troponin I values had a normal RV diameter as assessed by echocardiography, indicating that positive troponin I tests were significantly associated with RV dilatation (p = 0.009). Patients with positive troponin I tests had significantly more segmental defects in ventilation/perfusion lung scans than patients with normal serum troponin I (p = 0.0002).CONCLUSIONSOur data demonstrate that more than one-third of patients clinically diagnosed as having pulmonary embolism presented with elevated serum troponin I concentrations. Troponin I tests helped to identify patients with RV dilatation who had significantly more segmental defects in lung scans. Thus, troponin I assays are useful to detect minor myocardial damage in pulmonary embolism

Increasing Efficiency and Quality by Consolidation of Clinical Chemistry and Immunochemistry Systems with MODULAR ANALYTICS SWA

MODULAR ANALYTICS Serum Work Area (in USA Integrated MODULAR ANALYTICS, MODULAR ANALYTICS is a trademark of a member of the Roche Group) represents a further approach to automation in the laboratory medicine. This instrument combines previously introduced modular systems for the clinical chemistry and immunochemistry laboratory and allows customised combinations for various laboratory workloads. Functionality, practicability, and workflow behaviour of MODULAR ANALYTICS Serum Work Area were evaluated in an international multicenter study at six laboratories. Across all experiments, 236000 results from 32400 samples were generated using 93 methods. Simulated routine testing which included provocation incidents and anomalous situations demonstrated good performance and full functionality. Heterogeneous immunoassays, performed on the E-module with the electrochemiluminescence technology, showed reproducibility at the same level of the general chemistry tests, which was well within the clinical demands. Sample carryover cannot occur due to intelligent sample processing. Workflow experiments for the various module combinations, with menus of about 50 assays, yielded mean sample processing times of <38 minutes for combined clinical chemistry and immunochemistry requests; <50 minutes including automatically repeated samples. MODULAR ANALYTICS Serum Work Area offered simplified workflow by combining various laboratory segments. It increased efficiency while maintaining or even improving quality of laboratory processes

Multicentre performance evaluation of the E170 Module for MODULAR ANALYTICS

The E170 module was evaluated at 13 sites in an international multicentre study. The objective of the study was to assess the analytical performance of 49 analytes, and to collect feedback on the system's reliability and practicability. The typical, within-run coefficients of variation (CVs) for most of the quantitative assays ranged between 1 and 2% while a range of 2-4% was achieved with the infectious disease methods. Total precision CVs were found to be within the manufacturer's expected performance ranges, demonstrating good concordance of the system's measuring channels and a high reproducibility during the 2-4-week trial period. The functional sensitivity of 11 selected assays met the clinical requirements (e.g., thyreotroponin (TSH) 0.008 mU/l, troponin T 0.02 µg/l, total prostate-specific antigen (PSA) 0.03 µg/l). The E170 showed no drift during an 8-hour period and no relevant reagent carryover. Accuracy was confirmed by ring trial experiments and method comparisons vs. Elecsys® 2010. The reliability and practicability of the system's hardware and software met with, or even exceeded, the evaluator's requirements. Workflow studies showed that E170 can cover the combined workload of various routine analysers in a variety of laboratory environment. Throughput and sample processing time requirements were achieved while personnel ‘hands-on-time' could be reduce

Performance evaluation of a turbidimetric cystatin C assay on different high-throughput platforms

Objective. The goal with this study was to evaluate the analytical performance of a new cystatin C immunoassay (Tina-quant (R) a Cystatin C, Roche Diagnostics GmbH). The evaluation was carried out at four centers according to a standardized protocol. Material and methods. The Tina-quant (R) a Cystatin C is a latex particle-enhanced immunoturbidimetric assay. Roche cobas (R) 6000, MODULAR ANALYTICS SWA and COBAS INTEGRA (R) instruments were included in the study. Method comparison studies were carried out against two turbidimetric methods (Dako Cystatin C, Gentian Cystatin C), and one nephelometric method (Siemens N-Latex Cystatin C). Results. Linearity was proven throughout the measuring range from 0.4 to 8 mg/L. Within-run CVs ranged from 0.7-2.8%, and total CVs from 1.4-4.7 % (concentration range 0.6-3.9 mg/L). Comparable results were obtained with paired serum and Li-heparinate plasma samples. Good agreement was achieved in the comparisons between the Tina-quant (R) a Cystatin C assay and the other commercially available cystatin C assays, two different turbidimetric methods (slope range 0.88-1.04, intercept = 0.993) and one nephelometric assay (slope range 0.90-1.05, intercept = 0.986). Conclusions. The Tina-quant (R) a Cystatin C assay was shown to be precise and accurate with proven linearity over the measuring range. Good comparability was obtained with other commercially available assays for the determination of cystatin C. The Tina-quant (R) a Cystatin C assay is very well suited for clinical use on routine clinical chemistry analysers to detect renal dysfunction with a 24 h availability

Multicenter evaluation of analytical performance of the Liaison((R)) troponin I assay

Objectives: This study evaluated the analytical characteristics of the Liaison(R) immunoassay for cardiac troponin I (cTnI). Design and methods: The protocol consisted of eight sections: evaluation of antibody specificity, linearity, detection limit and imprecision, method comparison, evaluation of endogenous interferents, anticoagulant interference, sample stability, and reference values. Results: The assay equally measured free and complexed cTnI. The minimum detectable cTnI concentration was 0.021 mug/l. The cTnI concentration corresponding to a total CVof 10% was 0.056 mug/l. Linearity of response was demonstrated along the entire dynamic range of the assay. Assay interferences were minimal. cTnI concentrations in serum and heparinized plasma were significantly different. Values in EDTA plasma were on average approximately 5% higher than in matched serum, but this difference was not significant. The 99th percentile cTnI value in healthy subjects was 0.036 mug/l. Conclusions: Being sensitive, specific, and precise, the Liaison(R) cTnI assay meets current requirements to aid in the diagnosis of myocardial necrosis. (C) 2004 The Canadian Society of Clinical Chemists. All rights reserved