Daniel W. Rhodes

Prospective evaluation of pregnancy-associated plasma protein-a and outcomes in patients with acute coronary syndromes.

OBJECTIVES This study sought to investigate whether pregnancy-associated plasma protein-A (PAPP-A) is useful for risk assessment in non-ST-segment elevation acute coronary syndrome (NSTE-ACS). BACKGROUND PAPP-A is a high molecular weight, zinc-binding metalloproteinase that is associated with vulnerable plaque and may be a predictor of cardiovascular disease and mortality. METHODS We measured PAPP-A at baseline in 3,782 patients with non NSTE-ACS randomized to ranolazine or placebo in the MERLIN-TIMI 36 (Metabolic Efficiency With Ranolazine for Less Ischemia in Non-ST Elevation Acute Coronary Syndromes) trial and followed for an average of 1 year. A cut point of 6.0 μIU/ml was chosen from pilot work in this cohort. RESULTS PAPP-A >6.0 μIU/ml at presentation was associated with higher rates of cardiovascular death (CVD) or myocardial infarction (MI) at 30 days (7.4% vs. 3.7%, hazard ratio [HR]: 2.01; 95% confidence interval [CI]: 1.43 to 2.82; p < 0.001) and at 1 year (14.9% vs. 9.7%, HR: 1.63; 95% CI: 1.29 to 2.05; p < 0.001). PAPP-A was also associated with higher rates of CVD (HR: 1.94; 95% CI: 1.07 to 3.52, p = 0.027) and myocardial infarction (HR: 1.82; 95% CI: 1.22 to 2.71, p = 0.003) individually at 30 days. There was no difference in the risk associated with PAPP-A stratified by baseline cardiac troponin I [Accu-TnI >0.04 μg/l], p interaction = 0.87). After adjustment for cardiac troponin I, ST-segment deviation, age, sex, diabetes, smoking, hypertension, and coronary artery disease, PAPP-A was independently associated with CVD/myocardial infarction at 30 days (adjusted HR: 1.62, 95% CI: 1.15 to 2.29; p = 0.006) and 1 year (adjusted HR: 1.35, 95% CI: 1.07 to 1.71; p = 0.012). PAPP-A also improved the net reclassification for CVD/MI (p = 0.003). There was no significant interaction with ranolazine. CONCLUSIONS PAPP-A was independently associated with recurrent cardiovascular events in patients with NSTE-ACS. This finding supports PAPP-A as a candidate prognostic marker in patients with ACS and supports investigation of its therapeutic implications.

Absolute and relative changes (delta) in troponin I for early diagnosis of myocardial infarction: Results of a prospective multicenter trial

OBJECTIVES We investigated absolute and relative cardiac troponin I (TnI) delta changes, optimal sampling protocols, and decision thresholds for early diagnosis of myocardial infarction (MI). Serial cardiac biomarker values demonstrating a rise and/or fall define MI diagnosis; however the magnitude of change, timing, and diagnostic accuracy of absolute versus relative (percentage) deltas remains unsettled. METHODS We prospectively measured TnI (AccuTnI+3™, Beckman Coulter) at serial time intervals in 1929 subjects with chest pain or equivalent symptoms of acute coronary syndrome at 14 medical centers. Diagnosis was adjudicated by an independent central committee. RESULTS Elevated TnI above a threshold of 0.03ng/mL demonstrated significant diagnostic efficacy (AUC 0.96). For patients with TnI<0.03ng/mL and symptom onset≥8h, 99.1% (NPV) were diagnosed with conditions other than MI. Absolute delta performed significantly better than relative delta at 1-3h (AUC 0.84 vs 0.69), 3-6h (0.85 vs 0.73), and 6-9h (0.91 vs 0.79). Current recommendations propose ≥20% delta within 3-6h; however, results were optimized using an absolute delta of 0.01 or 0.02ng/mL. Sensitivity results for absolute delta at 1-3h and 3-6h (75.8%, 78.3%) were superior to relative delta (48.0%, 61.3%). NPV (rule out) was 99.6% when baseline TnI<0.03ng/mL and absolute delta TnI<0.01ng/mL. CONCLUSIONS Absolute delta performed significantly better than relative delta at all time intervals. Baseline TnI and absolute delta may be used in conjunction to estimate probability of MI. Consensus recommendations are supported for sampling on admission and 3h later, repeated at 6h in patients when clinical suspicion remains high.

Diagnostic performance of cardiac Troponin I for early rule-in and rule-out of acute myocardial infarction: Results of a prospective multicenter trial☆

OBJECTIVES To compare emergency department TnI serial sampling intervals, determine optimal diagnostic thresholds, and report representative diagnostic performance characteristics for early rule-in and rule-out of MI. METHODS We prospectively measured TnI (AccuTnI+3™, Beckman Coulter) at serial time intervals in 1929 subjects with chest pain or equivalent ischemic symptoms suggestive of acute coronary syndromes at 14 medical centers. Diagnosis was adjudicated by an independent central committee. RESULTS TnI ≥0.03ng/mL provided 96.0% sensitivity and 89.4% specificity at 1-3h after admission, and 94.9% sensitivity and 86.7% specificity at 3-6h. NPV (rule-out, non-MI) was 99.5% at 1-3h, and 99.0% at 3-6h when TnI is <0.03ng/mL. NPV was 99.1% when TnI is <0.03ng/mL and time of symptom onset is ≥8h. Approximately 50-58% (PPV) of patients with TnI ≥0.03ng/mL were diagnosed with MI, depending upon time from onset or admission; PPVs emphasize the importance of serial samples and delta TnI (rising or falling pattern) when low cutoffs are used. Nevertheless, even a single elevated TnI value increased the risk of MI. As TnI values rose, the probability of MI increased. Values ≥0.20ng/mL were associated with nearly 90% probability of MI. CONCLUSIONS We report a large multicenter prospective adjudicated trial assessing troponin for early rule-in and rule-out using the Universal Definition of MI and conducted in primary care hospital-associated emergency departments. Our study demonstrates high diagnostic accuracy at early observation times, and reinforces consensus recommendations for sampling on admission and 3h later, repeated at 6h when clinical suspicion remains high.

A European multicientre study on the comparison of HIV-1 viral loads between VERIS HIV-1 Assay and Roche COBAS® TAQMAN® HIV-1 test, Abbott RealTime HIV-1 Assay, and Siemens VERSANT HIV-1 Assay

BACKGROUND Viral load monitoring is essential for patients under treatment for HIV. Beckman Coulter has developed the VERIS HIV-1 Assay for use on the novel, automated DxN VERIS Molecular Diagnostics System.¥ OBJECTIVES: Evaluation of the clinical performance of the new quantitative VERIS HIV-1 Assay at multiple EU laboratories. STUDY DESIGN Method comparison with the VERIS HIV-1 Assay was performed with 415 specimens at 5 sites tested with COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 Test, v2.0, 169 specimens at 3 sites tested with RealTime HIV-1 Assay, and 202 specimens from 2 sites tested with VERSANT HIV-1 Assay. Patient monitoring sample results from 4 sites were also compared. RESULTS Bland-Altman analysis showed the average bias between VERIS HIV-1 Assay and COBAS HIV-1 Test, RealTime HIV-1 Assay, and VERSANT HIV-1 Assay to be 0.28, 0.39, and 0.61 log10 cp/mL, respectively. Bias at low end levels below 1000cp/mL showed predicted bias to be <0.3 log10 cp/mL for VERIS HIV-1 Assay versus COBAS HIV-1 Test and RealTime HIV-1 Assay, and <0.5 log10cp/mL versus VERSANT HIV-1 Assay. Analysis on 174 specimens tested with the 0.175mL volume VERIS HIV-1 Assay and COBAS HIV-1 Test showed average bias of 0.39 log10cp/mL. Patient monitoring results using VERIS HIV-1 Assay demonstrated similar viral load trends over time to all comparators. CONCLUSIONS The VERIS HIV-1 Assay for use on the DxN VERIS System demonstrated comparable clinical performance to COBAS® HIV-1 Test, RealTime HIV-1 Assay, and VERSANT HIV-1 Assay.

A European multicientre study on the comparison of HBV viral loads between VERIS HBV assay and Roche COBAS ® TAQMAN ® HBV test, Abbott RealTime HBV assay, Siemens VERSANT HBV assay, and Qiagen artus HBV RG kit

BACKGROUND Hepatitis B viral load testing is essential to treatment and monitoring decisions in patients with chronic Hepatitis B. Beckman Coulter has developed the VERIS HBV Assay (Veris) for use on the fully automated DxN VERIS Molecular Diagnostics System.1 OBJECTIVES: To evaluate the clinical performance of the Veris HBV Assay at multiple EU laboratories STUDY DESIGN: Method comparison was performed with a total of 344 plasma specimens from HBV infected patients tested with Veris and COBAS® TaqMan® HBV Test (Cobas), 207 specimens tested with Veris and RealTime HBV Assay (RealTime), 86 specimens tested with Veris and VERSANT® HBV Assay (Versant), and 74 specimens tested with Veris and artus® HBV RG PCR kit (artus). RESULTS Bland-Altman analysis showed average bias of -0.46 log10 IU/mL between Veris and Cobas, -0.46 log10IU/mL between Veris and RealTime, -0.36 log10IU/mL between Veris and Versant, and -0.12 log10IU/mL between Veris and artus. Bias was consistent across the assay range. Patient monitoring results using Veris demonstrated similar viral load trends over time to Cobas, RealTime, and artus. CONCLUSIONS The VERIS HBV Assay demonstrated comparable clinical performance, with varying degrees of negative bias, compared to other currently marketed assays for HBV DNA monitoring. This negative bias should be taken into consideration if switching monitoring methods to Veris.

European Multicenter Study on Analytical Performance of DxN Veris System HCV Assay

ABSTRACT The analytical performance of the Veris HCV Assay for use on the new and fully automated Beckman Coulter DxN Veris Molecular Diagnostics System (DxN Veris System) was evaluated at 10 European virology laboratories. Precision, analytical sensitivity, specificity, and performance with negative samples, linearity, and performance with hepatitis C virus (HCV) genotypes were evaluated. Precision for all sites showed a standard deviation (SD) of 0.22 log10 IU/ml or lower for each level tested. Analytical sensitivity determined by probit analysis was between 6.2 and 9.0 IU/ml. Specificity on 94 unique patient samples was 100%, and performance with 1,089 negative samples demonstrated 100% not-detected results. Linearity using patient samples was shown from 1.34 to 6.94 log10 IU/ml. The assay demonstrated linearity upon dilution with all HCV genotypes. The Veris HCV Assay demonstrated an analytical performance comparable to that of currently marketed HCV assays when tested across multiple European sites.

A European multicentre study on the comparison of HCV viral loads between VERIS HCV assay and COBAS® TaqMan® HCV Test and RealTime HCV Assay

BACKGROUND Beckman Coulter has developed the VERIS HCV Assay for use on the new fully automated DxN VERIS Molecular Diagnostic System¥ for HCV viral load monitoring. OBJECTIVES Evaluate the clinical performance of the new quantitative VERIS HCV Assay. STUDY DESIGN Comparison was performed on 279 plasma specimens from HCV infected patients tested with the VERIS HCV Assay and COBAS® Ampliprep/COBAS® Taqman® HCV Test and 369 specimens tested with the VERIS HCV Assay and RealTime HCV Assay. Patient monitoring sample results from four time points were also compared. RESULTS The average bias between the VERIS HCV Assay and the COBAS® Ampliprep/COBAS® Taqman® HCV Test was 0.04 log10IU/mL, while between the VERIS HCV Assay and the RealTime HCV Assay average bias was 0.21 log10IU/mL. Bias, however, was not consistent across the measuring range. Analysis at the lower end of quantification levels 50, 100, and 1000IU/mL showed a predicted bias for VERIS HCV Assay versus COBAS® Ampliprep/COBAS® Taqman® HCV Test between -0.42 and -0.22 log10IU/mL and for VERIS HCV Assay versus RealTime HCV Assay between 0.00 and 0.13 log10IU/mL. Patient monitoring of HCV viral load over time demonstrated similar levels between VERIS HCV Assay results and COBAS® Ampliprep/COBAS® Taqman® HCV Test (52 samples from 13 patients) and RealTime HCV Assay (112 samples from 28 patients). CONCLUSIONS VERIS HCV Assay for use on the DxN VERIS Molecular Diagnostic System represents a reliable new tool for easy sample to result HCV RNA viral load monitoring.

European Multicenter Study on Analytical Performance of Veris HIV-1 Assay

ABSTRACT The analytical performance of the Veris HIV-1 assay for use on the new, fully automated Beckman Coulter DxN Veris molecular diagnostics system was evaluated at 10 European virology laboratories. The precision, analytical sensitivity, performance with negative samples, linearity, and performance with HIV-1 groups/subtypes were evaluated. The precision for the 1-ml assay showed a standard deviation (SD) of 0.14 log10 copies/ml or less and a coefficient of variation (CV) of ≤6.1% for each level tested. The 0.175-ml assay showed an SD of 0.17 log10 copies/ml or less and a CV of ≤5.2% for each level tested. The analytical sensitivities determined by probit analysis were 19.3 copies/ml for the 1-ml assay and 126 copies/ml for the 0.175-ml assay. The performance with 1,357 negative samples demonstrated 99.2% with not detected results. Linearity using patient samples was shown from 1.54 to 6.93 log10 copies/ml. The assay performed well, detecting and showing linearity with all HIV-1 genotypes tested. The Veris HIV-1 assay demonstrated analytical performance comparable to that of currently marketed HIV-1 assays. (DxN Veris products are Conformité Européenne [CE]-marked in vitro diagnostic products. The DxN Veris product line has not been submitted to the U.S. FDA and is not available in the U.S. market. The DxN Veris molecular diagnostics system is also known as the Veris MDx molecular diagnostics system and the Veris MDx system.)

A European multicenter study on the analytical performance of the VERIS HBV assay

BACKGROUND Hepatitis B viral load monitoring is an essential part of managing patients with chronic Hepatits B infection. Beckman Coulter has developed the VERIS HBV Assay for use on the fully automated Beckman Coulter DxN VERIS Molecular Diagnostics System.1 OBJECTIVES: To evaluate the analytical performance of the VERIS HBV Assay at multiple European virology laboratories. STUDY DESIGN Precision, analytical sensitivity, negative sample performance, linearity and performance with major HBV genotypes/subtypes for the VERIS HBV Assay was evaluated. RESULTS Precision showed an SD of 0.15 log10 IU/mL or less for each level tested. Analytical sensitivity determined by probit analysis was between 6.8-8.0 IU/mL. Clinical specificity on 90 unique patient samples was 100.0%. Performance with 754 negative samples demonstrated 100.0% not detected results, and a carryover study showed no cross contamination. Linearity using clinical samples was shown from 1.23-8.23 log10 IU/mL and the assay detected and showed linearity with major HBV genotypes/subtypes. CONCLUSIONS The VERIS HBV Assay demonstrated comparable analytical performance to other currently marketed assays for HBV DNA monitoring.