-
Bo Jørgensen,
Thomas Bertsch,
Hans-Joachim Bröker,
Markus Schäfer,
Jean-Paul Chapelle,
Romy Gadisseur,
Martin R Cowie,
Bert Dikkeschei,
Eberhard Gurr,
Wiebke Hayen,
Gerd Hafner,
Yuriko Stiegler,
Hans-Robert Schönherr,
Ruth H Strasser,
Britta Weidtmann,
Henning Folkerts,
Christian Zugck,
Kerstin Hofmann, Rainer Zerback
[show abstract]
[hide abstract]
ABSTRACT: In the second generation of the point-of-care (POC) assay Roche CARDIAC proBNP, the upper limit of the measuring range was extended from 3000 to 9000 ng/L.
A thirteen-site multicentre evaluation was carried out to assess the analytical performance of the POC NT-proBNP assay and to compare it with a laboratory N-terminal pro-brain natriuretic peptide (NT-proBNP) assay.
In method comparisons of six lots of POC NT-proBNP with the lab reference method (Elecsys proBNP) mean bias ranged from -10 to +17%. In lot-to-lot comparisons all six investigated lots of POC NT-proBNP showed excellent agreement, with mean bias between -7% and +2%. The majority of all coefficients of variation obtained from ten-fold measurements using 56 native blood samples were below 8%. No interference was observed with hemolytic blood (hemoglobin concentrations up to 0.12 mmol/L), lipemic blood (triglyceride concentrations up to 14.0 mmol/L) nor icteric blood (bilirubin concentrations up to 63 micromol/L). Hematocrit values between 24% and 51% had no influence on the assay result. High NT-proBNP concentrations above the measuring range of POC NT-proBNP did not lead to false low results due to potential high-dose hook effect. Results with POC NT-proBNP were not influenced by different ambient temperatures (18 degrees C to 32 degrees C), the sample material used, nor by over- or underdosing by 15 microL compared to the regular sample volume of 150 microL.
The POC NT-proBNP assay showed an excellent analytical performance including a good agreement with the laboratory method. The assay is therefore suitable for its intended use in point-of-care settings.
Clinical laboratory 01/2012; 58(5-6):515-25. · 0.90 Impact Factor
-
Markus Schäfer,
Hans-Joachim Bröker,
Andreas Luchner,
Carsten Jungbauer,
Christian Zugck,
Veselin Mitrovic,
Roland Willenbrock,
Robert R. Flieger,
Bret A. Wittmer,
Mark W. Graves,
Kerstin Fluder, Rainer Zerback,
for the CARPRO Multicentre Study Group
[show abstract]
[hide abstract]
ABSTRACT: Context: Point-of-care assays allow to have analytical results available at the site of patient care delivery such as the emergency department or the intensive care unit.
Objective: To demonstrate equivalence in the N-terminal (NT) pro-brain natriuretic peptide (proBNP) concentrations as measured by the point-of-care assay (POC NT-proBNP) in comparison to the laboratory assay (lab NT-proBNP) in patients with heart failure and in a reference population.
Design: Multicenter study at 7 sites. The following were eligible for data analysis: 217 patients with heart failure and 189 individuals from a reference population (patients with hypertension, diabetes, chronic obstructive pulmonary disease or asthma, or apparently healthy individuals). For all study participants, NT-proBNP values both with the POC and with the laboratory assay, echocardiographic and spirometry data, and the New York Heart Association classification were available.
Results: In method comparisons between POC NT-proBNP and lab NT-proBNP, the slope of the regression line was 0.99 and the correlation coefficient was 0.97. Testing on diagnostic equivalence, POC NT-proBNP versus lab NT-proBNP yielded a mean logarithmic methodical difference of −4.9% in patients with heart failure and +3.5% with the reference population. Using an age-independent cutoff of 125 ng/L, the diagnostic sensitivity of POC NT-proBNP and of lab NT-proBNP was found to be 89%, and the areas under the receiver operating characteristic curves were 0.88 or 0.89, respectively.
Conclusions: Our multicenter study has demonstrated the diagnostic equivalence of POC NT-proBNP with lab NT-proBNP both in the diagnosis of heart failure and in the differential diagnosis of a reference population. Consequently, clinical experiences and indications with the laboratory assay could be applied to the POC assay as well.
Point of Care The Journal of Near-Patient Testing & Technology 05/2010; 9(2):91-97.
-
[show abstract]
[hide abstract]
ABSTRACT: The cobas h 232 point-of-care analyzer by Roche is the instrument successor of the Cardiac reader allowing the quantitative determination of troponin T, creatine kinase MB, myoglobin, NT-proBNP and D-dimer.
In this study 1329 patients with acute coronary syndromes, heart failure, thromboembolic or other diseases and 945 healthy donors were assessed. Comparisons versus central laboratory methods were carried out with 2379 samples from these individuals; out of these, 1591 samples gave quantitative results within the measuring range and were included in the evaluation.
The point-of-care assays for creatine kinase MB, myoglobin, NT-proBNP and D-dimer were within a relative bias range of -5.9 to +6.9% compared to the laboratory assay. The troponin T assay showed a bias of -11.0% and after change of the calibration procedure of +1.9%. None of the five point-of-care assays had a relative difference between the new system and the precursor device that was higher than +5.0%. Within-series coefficients of variation of patient samples were found in a range from 4.8 to 14.8%. No significant interference was observed with lipemic, hemolytic and icteric blood or at different hematocrit values.
Due to its good analytical agreement with the laboratory methods and with its precursor device, the cobas h 232 system can be reliably used to support on-site decision making for cardiovascular patients in acute and non-acute settings.
Clinical laboratory 01/2010; 56(1-2):37-49. · 0.90 Impact Factor
-
Evangelos Giannitsis,
Hannsjörg Baum,
Thomas Bertsch,
Martin Juchum,
Margit Müller-Bardorf,
Bo Jørgensen,
Agathe Böhmer,
Martina Rebmann,
Jürgen Schäffler,
Michael Schwab, Rainer Zerback
[show abstract]
[hide abstract]
ABSTRACT: The point-of-care (POC) test Roche CARDIAC CK-MB is a new assay which has been developed for the existing Roche Cardiac reader system.
We performed a multicentre evaluation at six sites to assess the analytical performance of the POC CK-MB assay and to compare it with a quantitative laboratory CK-MB assay.
Within-series coefficients of variation (CV) resulting from 34 ten-fold measurements with patient samples ranged from 4.3% to 16.4%. Using quality control material, the mean CV values for day-to-day imprecision were 6.5% for the low level control and 8.4% for the high level control. Based upon 847 pairs of values, the mean relative bias of three independently calibrated lots of the POC CK-MB assay ranged from -6% to -11% in method comparisons with the lab CK-MB assay. The mean relative lot-to-lot differences of POC CK-MB were between -2% and +1%. No interference was observed with lipaemic blood (triglyceride concentrations up to 8.1 mmol/L), icteric blood (bilirubin concentrations up to 513 micromol/L), haemolytic blood (haemoglobin concentrations up to 0.12 mmol/L), biotin (up to 30 mg/L) and rheumatoid factor (up to 119 IU/mL), or with 53 standard or cardiological drugs even in toxic concentrations. There was no influence on the results by varying haematocrit values in the range from 21% to 54%. A slight interference with human anti-mouse antibodies type 2 was found. No significant influence on the results with POC CK-MB was found by using sample volumes between 135 and 165 microL. High CK-MB concentrations above the measuring range of POC CK-MB (1-40 microg/L) did not lead to false low results due to potential high-dose hook effect. No significant effect of sample age on recovery occurred up to a sample age of 24 h. No cross-reactivity was found between the POC CK-MB assay and either CK-MM or CK-BB. A substudy with healthy individuals confirmed the reference limits of 3.8 microg/L for females and 6.7 microg/L for males.
The POC CK-MB assay showed a very good analytical performance with an excellent concordance with the calibration and reference laboratory method. It should be therefore suitable for its intended use in POC settings. Clin Chem Lab Med 2008;46:630-8.
Clinical Chemistry and Laboratory Medicine 02/2008; 46(5):630-8. · 2.15 Impact Factor
-
Thomas Bertsch,
Bert Dikkeschei,
Eberhard Gurr,
Wiebke Hayen,
Bo Jørgensen,
Johannes Lotz,
Margit Müller-Bardorff,
Jordi Ordóñez-Llanos,
Ilse Schulz,
Jürgen Spinke,
Marcel Thiele, Rainer Zerback
[show abstract]
[hide abstract]
ABSTRACT: A new point-of-care test for the determination of NT-proBNP in whole blood was developed based on the existing gold-label rapid immunoassay technology of the Roche Cardiac reader system. The novel gold-labelled monoclonal antibody recognizes NT-proBNP at amino acid sequence 27 to 31, the biotinylated polyclonal antibody recognizes sequence 39 to 50. In a model assay based upon the reference method Elecsys proBNP and with an R & D lot of the point-of-care test, this newly selected and developed combination of antibodies showed a very good correlation with the standard Elecsys proBNP assay with correlations of 0.96 or 0.94, respectively. The test was calibrated according to the existing masterlot concept of the Roche CARDIAC tests with Elecsys proBNP as a reference. In a preliminary method comparison with Elecsys proBNP the accuracy of the calibration was confirmed; the bias was between 1 and 6%. Possible reasons of approximately 1% outliers (> +/- 100%) were discussed.
Clinical laboratory 01/2007; 53(7-8):423-31. · 0.90 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: D-dimer assays are efficient in the exclusion diagnostics of deep vein thrombosis (DVT) in patients without severe concomitant diseases. We have determined diagnostic sensitivity and specificity of a new point-of-care rapid assay for quantitative determination of D-dimer in heparinized whole blood in outpatients with suspected DVT. In 19 participating centers, 637 patients were included in the study, of which 77 were excluded, the majority because of inadequate documentation of analytical quality control measures. DVT was diagnosed in 223 of the remaining 560 patients by duplex ultrasound examination. The POC D-dimer assay showed a high sensitivity of 96.9% for the diagnosis of DVT and a high specificity of 60.8% at a pre-specified cutoff of 0.5 microg/ml. For Tina-quant D-dimer, sensitivity was slightly lower at 94.9%, with a specificity of 64.8%. The VIDAS D-dimer assay showed a sensitivity of 98.2%, but specificity was 40.7%. The area under the curve (AUC +/- standard error, 95% confidence interval) was 0.879 +/- 0.019 (0.845-0.909) for POC D-dimer, 0.908 +/- 0.016 (0.877-0.934) for Tina-quant D-dimer, and 0.895 +/- 0.018 (0.862-0.922) forVIDAS D-dimer. Differences were not statistically significant. The new whole blood POC D-dimer assay is a reliable tool for exclusion of DVT in symptomatic outpatients, displaying a comparable diagnostic performance as VIDAS D-dimer and Tina-quant D-dimer assays.
Thrombosis and Haemostasis 08/2006; 96(1):79-83. · 5.04 Impact Factor
-
Jordi Ordóñez-Llanos,
Miquel Santaló-Bel,
Javier Mercé-Muntañola,
Paul O Collinson,
David Gaze,
Markus Haass,
Hugo A Katus,
Frank Chwallek,
Michael M Hirschl,
Ulla Derhaschnig,
Margit Mueller-Bardorff,
John Kellett,
Christer Sylvén,
Ilse Schulz, Rainer Zerback
[show abstract]
[hide abstract]
ABSTRACT: A prospective multicenter study including 1410 chest pain patients with suspected acute coronary syndromes was carried out to examine the predictive value of biological cardiac markers for adverse events measured by a point-of-care system. Admission cardiac troponin T (cTnT) and myoglobin were measured in parallel on a point-of-care system in the emergency department and -- together with CK-MB mass -- on lab analyzers. In a one-year follow-up, cardiac and non-cardiac death, acute myocardial infarction, unstable angina pectoris and need for revascularization were registered. Median time between onset of symptoms and admission was 285 min; 172 patients (12.2%) had no event during follow-up. If the cTnT, measured either by the point-of-care system or a conventional lab analyzer, was >0.05 microg/L, then the chance of a cardiac event during the follow-up period was doubled (18% vs. 9%). Serial cTnT measurement did not add any further value to the predictive power of the admission cTnT. Myoglobin and CK-MB mass identified increasing risk with increasing concentration quartiles; cardiac event rates were 2.8- to 4.4-fold higher between the quartiles with the lowest and those with the highest analyte concentration, respectively. There was no difference in non-cardiac death rates between any concentration quartiles. In conclusion, the prediction of clinical events by cardiac troponin T and myoglobin measured with a point-of-care analyzer in the emergency department was as good as that of the same cardiac markers and CK-MB mass measured on lab analyzers.
Clinica Chimica Acta 03/2006; 365(1-2):93-7. · 2.54 Impact Factor
-
Christian Zugck,
Manfred Nelles,
Hugo A Katus,
Paul O Collinson,
David C Gaze,
Bert Dikkeschei,
Eberhard Gurr,
Wiebke Hayen,
Markus Haass,
Christoph Hechler,
Viviane van Hoof,
Khadija Guerti,
Carl van Waes,
Gert Printzen,
Kai Klopprogge,
Ilse Schulz, Rainer Zerback
[show abstract]
[hide abstract]
ABSTRACT: The Roche CARDIAC proBNP point-of-care (POC) test is the first test intended for the quantitative determination of N-terminal pro-brain natriuretic peptide (NT-proBNP) in whole blood as an aid in the diagnosis of suspected congestive heart failure, in the monitoring of patients with compensated left-ventricular dysfunction and in the risk stratification of patients with acute coronary syndromes.
A multicentre evaluation was carried out to assess the analytical performance of the POC NT-proBNP test at seven different sites.
The majority of all coefficients of variation (CVs) obtained for within-series imprecision using native blood samples was below 10% for both 52 samples measured ten times and for 674 samples measured in duplicate. Using quality control material, the majority of CV values for day-to-day imprecision were below 14% for the low control level and below 13% for the high control level. In method comparisons for four lots of the POC NT-proBNP test with the laboratory reference method (Elecsys proBNP), the slope ranged from 0.93 to 1.10 and the intercept ranged from 1.8 to 6.9. The bias found between venous and arterial blood with the POC NT-proBNP method was < or =5%. All four lots of the POC NT-proBNP test investigated showed excellent agreement, with mean differences of between -5% and +4%. No significant interference was observed with lipaemic blood (triglyceride concentrations up to 6.3 mmol/L), icteric blood (bilirubin concentrations up to 582 micromol/L), haemolytic blood (haemoglobin concentrations up to 62 mg/L), biotin (up to 10 mg/L), rheumatoid factor (up to 42 IU/mL), or with 50 out of 52 standard or cardiological drugs in therapeutic concentrations. With bisoprolol and BNP, somewhat higher bias in the low NT-proBNP concentration range (<175 ng/L) was found. Haematocrit values between 28% and 58% had no influence on the test result. Interference may be caused by human anti-mouse antibodies (HAMA) types 1 and 2. No significant influence on the results with POC NT-proBNP was found using volumes of 140-165 muL. High NT-proBNP concentrations above the measuring range of the POC NT-proBNP test did not lead to false low results due to a potential high-dose hook effect.
The POC NT-proBNP test showed good analytical performance and excellent agreement with the laboratory method. The POC NT-proBNP assay is therefore suitable in the POC setting.
Clinical Chemistry and Laboratory Medicine 02/2006; 44(10):1269-77. · 2.15 Impact Factor
-
David Gaze,
Paul O. Collinson,
Markus Haass,
Ulla Derhaschnig,
Michael M. Hirschl,
Hugo A. Katus,
Frank Chwallek,
Margit Mueller-Bardorff,
John Kellett,
Jordi Ordóñez-Llanos,
Miquel Santaló-Bel,
Javier Mercé-Muntañola,
Christer Sylvén,
Ilse Schulz, Rainer Zerback,
for the CARMYT Multicentre Study Group
[show abstract]
[hide abstract]
ABSTRACT: The goal of this study was to examine whether point-of-care testing of cardiac markers in emergency departments or coronary care units generates a substantial reduction of the turnaround time compared with central laboratory testing. A total of 4609 samples from patients with suspected acute coronary syndromes attending each of 5 participating hospitals were used to measure cardiac troponin Ton a point-of-care system at the bedside, and 3447 of these samples were simultaneously sent to each hospital's central laboratory for an emergency determination of total CK. The time to central laboratory result varied broadly (from 52-147 minutes) from hospital to hospital. There was little difference between the hospitals in the time to result for the point-of-care system (range, 12-22 minutes). The overall gain in time from point-of-care testing compared with central laboratory measurements was 65 minutes (range, 34-135 minutes).
Point of Care The Journal of Near-Patient Testing & Technology 11/2004; 3(4):156-158.
-
Ulla Derhaschnig,
Michael M. Hirschl,
Paul O. Collinson,
David Gaze,
Markus Haass,
Hugo A. Katus,
Frank Chwallek,
Margit Mueller-Bardorff,
John Kellett,
Jordi Ordóñez-Llanos,
Miquel Santaló-Bel,
Javier Mercé-Muntañola,
Christer Sylvén,
Ilse Schulz, Rainer Zerback,
for the CARMYT Multicentre Study Group
[show abstract]
[hide abstract]
ABSTRACT: This study was carried out to compare the time-dependent diagnostic sensitivity and specificity for acute myocardial infarction of 2 point-of-care tests for troponin T and myoglobin measured in routine use of coronary care units with those of the respective laboratory tests. A total of 794 consecutive patients with suspected acute coronary syndromes admitted to the coronary care units of 6 hospitals were enrolled in the study. Point-of-care tests and laboratory tests were measured in parallel from samples obtained serially on admission, and at 1, 2, 4, 6 to 8, 12, 24, and 48 hours from admission. The point-of-care tests achieved maximum sensitivities of 96% (troponin T) and 72% (myoglobin); and the maximum sensitivities of the laboratory tests were 96%, 81%, and 83% for troponin T, myoglobin, and CK-MB mass respectively. The specificities varied from 90 to 94% for point-of-care troponin T, 83 to 93% for point-of-care myoglobin, 97 to 99% for laboratory troponin T, 79 to 85% for laboratory myoglobin, and 95 to 100% for laboratory CK-MB mass. The following maximum areas under receiver-operator characteristics curves were obtained (at different times): point-of-care troponin T, 0.97; point-of-care myoglobin, 0.87; laboratory troponin T, 0.99; laboratory myoglobin, 0.89; and laboratory CK-MB mass, 0.96. In conclusion the point-of-care tests had a comparable clinical performance as established cardiac markers performed in the laboratory.
Point of Care The Journal of Near-Patient Testing & Technology 11/2004; 3(4):162-164.
-
John Kellett,
Michael M. Hirschl,
Ulla Derhaschnig,
Paul O. Collinson,
David Gaze,
Markus Haass,
Hugo A. Katus,
Frank Chwallek,
Margit Mueller-Bardorff,
Jordi Ordóñez-Llanos,
Javier Mercé-Muntañola,
Miquel Santaló-Bell,
Christer Sylvén,
Ilse Schulz, Rainer Zerback,
for the CARMYT Multicentre Study Group
[show abstract]
[hide abstract]
ABSTRACT: The authors report a multicenter study on the diagnostic efficiency of 2 point-of-care tests for troponin T and myoglobin in patients with nondiagnostic electrocardiogram (EKG). A total of 341 consecutive patients with a final diagnosis of acute myocardial infarction admitted to 5 hospitals were included in the study, 172 of whom had no detectable ST-segment elevation or Q-wave change in any of their EKGs performed during the first 4 hours after presentation. Troponin T and myoglobin were quantitatively determined on a point-of-care system in whole blood samples drawn on admission, and 1, 2, and 4 hours later. During the first 4 hours after presentation, the troponin T test used alone achieved a sensitivity of 75 to 94%, and combining both tests improved sensitivity by a further 4 to 16%. Four hours after presentation both tests were negative in only 3 acute myocardial infarction patients (2%). These diagnostic sensitivities for acute myocardial infarction in patients with a non-diagnostic EKG were comparable with those patients with a diagnostic EKG.
Point of Care The Journal of Near-Patient Testing & Technology 11/2004; 3(4):159-161.
-
[show abstract]
[hide abstract]
ABSTRACT: The rapid troponin T assay CARDIAC T Quantitative was recalibrated using Elecsys Troponin T 3rd Generation as a new reference method. This paper presents the method comparisons at six centres using the new reference method. Method comparison between CARDIAC T Quantitative versus Elecsys Troponin T 3rd Generation were performed using 319 samples from patients with acute coronary syndromes. The quality of the CARDIAC T Quantitative was controlled by a daily single determination of CARDIAC Control Troponin T, and for the Elecsys Troponin T 3rd Generation, the Elecsys controls were included in each run. The results for the control materials for the CARDIAC T Quantitative were between 93% and 107% of the target values. The CV ranged from 7% to 16%. From the regression analysis, according to Bablok and Passing (y=1.07x) and the Bland and Altman plot, the bias between CARDIAC T Quantitative and Elecsys Troponin T 3rd Generation is from +6% to +7%. The correlation coefficient is 0.93, and a 3×3 comparison of the clinical efficiency yielded 92% clinical concordance between CARDIAC T Quantitative and Elecsys Troponin T 3rd Generation. In conclusion, CARDIAC T Quantitative was in good agreement with the reference and calibration method Elecsys Troponin T 3rd Generation.
Clinica Chimica Acta 06/2001; · 2.54 Impact Factor
