Beckman Coulter Foundation

BackgroundThe analytical performance characteristics of the BD‐Tau (brain‐derived Tau) immunoassay currently under development on the Beckman Coulter Access 2 and DxI 9000 Access analyzers is described. BD‐Tau measurement is being under investigation as a tool to differentiate between multiple types of dementia and as an indicator of neurologic injury.MethodThe prototype BD‐Tau assay is a two‐step sandwich assay utilizing an anti‐N‐terminal Tau monoclonal (mAb) antibody/alkaline phosphatase conjugate and paramagnetic particles coated with an anti‐BD‐Tau mAb. The assay time to first result is ∼35 minutes. Sixty‐nine EDTA plasma and serum samples from subjects with Alzheimer's disease (AD; n = 29) or frontotemporal dementia (FTD; n = 29) and 20 age‐matched healthy, normal control subjects were evaluated. A method comparison was performed between Access 2 and DxI 9000.ResultThe prototype BD‐Tau assay has a targeted analytical measuring range of up to approximately s2000 pg/mL. 100% of normal control samples were quantified, with low dose variability (<4.0% coefficient of variation). Comparison of the prototype BD‐Tau assay on DxI 9000 and Access 2 yielded a Passing‐Bablok slope of 1.16 (r=0.999) and an intercept of ‐0.05 pg/mL. The dose ratios of the median of AD over the median of normal samples for Access 2 and DxI 9000 were 2.0 and 1.6, respectively; AD patient median dose values were 5.6 pg/mL and 4.5 pg/mL, respectively. Normal sample median dose value was 2.8 pg/mL on both platforms. On Access 2 and DxI 9000, the FTD median dose values were 6.2 pg/mL and 5.4 pg/mL, respectively; the dose ratios of median FTD over median of normal samples were 2.2 and 1.9, respectively. This assay can be used for both plasma and serum. Comparison of serum against EDTA plasma on the DxI 9000 analyzer yielded a Passing‐Bablok slope of 0.96 (r=0.988) and an intercept of 0.02 pg/mL across 47 matched samples, including AD, FTD, and controls.ConclusionThe first high‐throughput, fully automated BD‐Tau assay provides fast, highly sensitive, precise results on the Beckman Coulter Access 2 and DxI 9000 platforms. It presents high selectivity between individuals without neurodegenerative disease versus AD and FTD subjects.

Abstract Description Cells exhibit an inherent fluorescence called autofluorescence (AF) caused by cellular components and metabolites that fluoresce upon excitation by specific wavelengths of light. Common endogenous fluorophores include cyclic compounds such as reduced pyridine nucleotides (NADH), oxidized flavin coenzymes (FMN and FAD), vitamins, and proteins containing aromatic amino acids like tryptophan, phenylalanine and tyrosine. The analysis of flow cytometry data can be complicated by the presence of cells intrinsic AF: interfering with the precise detection of the desired fluorescence signals, particularly for low-abundance markers or dim populations. In addition, AF can lead to unmixing errors. To test AF extraction on the CytoFLEX mosaic spectral detection module, we stained a 100 ul whole blood sample with a combination of fluorochromes that are either within or outside of the expected AF range of white blood cells. Samples were acquired using the CytoFLEX mosaic spectral detection module. During unmixing, 4 AF populations could be identified corresponding with different spectra and fluorescent signatures. After removing highly similar AF spectra, 2 unique signatures remained. Including these 2 unique AF spectra in the unmixing increased the resolution for the fluorochromes within the expected AF range. In conclusion, this work demonstrates the effectiveness of using multiple AF signatures for AF extraction on the CytoFLEX mosaic spectral detection module in complex samples. Funding Sources N/A Topic Categories Technological Innovations in Immunology (TECH)

Abstract Background Beckman Coulter, Inc. has recently developed a fully automated Access anti-hepatitis A Virus (HAV) assay* for the detection of antibodies to HAV (IgG and IgM) for use on the DxI 9000 Immunoassay Analyzer. The assay*s analytical and clinical performances were evaluated. Methods Imprecision was evaluated using three replicates of eight samples and two quality controls using multiple reagent packs and calibrator lots in 40 runs based on CLSI EP05-A3. Reproducibility was evaluated at three US clinical laboratories using one lot of reagent, low/high negative and positive samples, and quality controls based on CLSI EP05-A3. Cross-reactivity was evaluated using 234 negative samples and a reference method across 22 categories including other viral infection and auto-immune diseases. Access anti-HAV assay sensitivity for early detection was assessed on four seroconversion panels. Access anti-HAV assay clinical diagnostic performance was evaluated in comparison to commercially available FDA-cleared anti-HAV reference assays at three US clinical laboratories to evaluate the assay’s ability as an aid in the diagnosis of current or past HAV infection and to determine the presence of an antibody response to HAV in vaccine recipients. Results Total imprecision demonstrated = 5.9 % CV for samples = 1.00 S/CO, and total standard deviation (SD) = 0.05 for samples &amp;lt; 1.00 S/CO while reproducibility demonstrated an overall imprecision &amp;lt; 8% for samples = 1.00 S/CO (n=360) and an SD of &amp;lt; 0.04 for samples &amp;lt; 1.00 S/CO (n=360). The cross-reactivity study demonstrated overall negative agreement of 99.6% versus the reference assay. Seroconversion testing results demonstrated that the Access anti-HAV assay is equivalent in sensitivity to the reference assay. The Access anti-HAV assay demonstrated overall PPA of 98.8% (n=810/820; 95% CI: 97.8-99.3%) and NPA of 98.5% (n=334/339; 95% CI: 96.6-99.4%) in the diagnostic population. The HAV antibody response to vaccination, i.e. pre- and post- vaccination (n=59), demonstrated PPA and NPA of 100% with a 95% CI of 93.9-100.0%. Conclusion The Access anti-HAV assay demonstrated excellent analytical and clinical performance equivalent to currently FDA-cleared anti-HAV assays. Beckman Coulter, the stylized logo, and the Beckman Coulter product and service marks mentioned herein are trademarks or registered trademarks of Beckman Coulter, Inc. in the United States and other countries. All other trademarks are the property of their respective owners. *For Investigational Use only. The Access anti-HAV assay is pending premarket clearance by the United States Food and Drug Administration; not yet available for in vitro diagnostic use in the US.

Abstract Background Aztreonam-avibactam (AZA) is a novel antibiotic combination for treating Gram-negative bacterial infections, including metallo-β-lactamase-producing multidrug-resistant pathogens for which there are limited or no treatment options.1 Given the need for accurate antimicrobial susceptibility testing results, a study was conducted with clinical isolates of Enterobacterales, Pseudomonas species, and Stenotrophomonas maltophilia on an investigational MicroScan Dried Gram-negative MIC (MSDGN) panel with AZA.2 Methods Three clinical sites evaluated MSDGN MIC values to MICs from CLSI reference panels. The study included 602/671 Enterobacterales, 53/59 Pseudomonas species and 69/70 S. maltophilia isolates using Prompt or turbidity inoculation. MSDGN panels were incubated at 35 ± 1°C and read on the WalkAway, autoSCAN-4, and visually at 16-20 hours. Reference panels were prepared according to CLSI methodology, incubated 16-20 hours for Enterobacterales and Pseudomonas species, and 20-24 hours for S. maltophilia and read visually. Results Essential agreement was calculated comparing MSDGN panel MIC results against reference panel MIC results for all isolates (Table 1). Conclusions AZA MIC results for Enterobacterales, Pseudomonas species, and S. maltophilia from MSDGN panels correlate well with MICs obtained using reference panels in this study. 1Pending approval by US Food and Drug Administration (FDA); not available for in vitro diagnostic use in the US. Not for Distribution in the US. 2Pending submission and clearance by the US FDA; not yet available for in vitro diagnostic use in the US. For Investigational Use Only. The performance characteristics of this product have not been established. In development, pending achievement of CE compliance; not yet available for in vitro diagnostic use. © 2024 Beckman Coulter. All rights reserved. All other trademarks are the property of their respective owners. BEC, the stylized logo and the BEC product and service marks mentioned herein are trademarks or registered trademarks of BEC, Inc. in the US and other countries. 2023-12350

Abstract Background The DxC 500i Clinical Analyzer* is Beckman Coulter’s latest integrated Clinical Chemistry and Immunoassay analyzer. It provides reliability, scalability, and workflow efficiency via a flexible independent maintenance mode, increased uptime, and a dynamic sample handler to optimize sample management. Standard Beckman Coulter Chemistry and Immunoassay consumables and reagents ensure network standardization and commutability. The purpose of this study was to evaluate the analytical performance of the new DxC 500i analyzer and to compare the performance against the Beckman Coulter stand-alone Clinical Chemistry and Immunoassay analyzers on the market. Methods To assess performance over a range of assay methodologies, several DxC 500i Beckman Coulter Immunoassays and Chemistry assays were evaluated. Precision was assessed using human samples following CLSI EP05-A3 guidelines. Linear range was assessed following CLSI EP06-A guidelines. Method Comparison and Bias Estimation studies compared the DxC 500i Clinical Analyzer against the Access 2 Immunoassay System, the AU480 and the DxC 700 AU Clinical Chemistry analyzers, following CLSI EP09c-ED3 guidelines. To investigate carryover potential as samples are processed across the integrated system, a carryover study was designed. This focused on evaluating potential sample-to-sample carryover caused by the AU sample probe and its effects on immunoassay samples during reflex scenarios. Results DxC 500i Chemistry results: Glucose Serum (OSR6x21) Assessments of repeatability and within laboratory precision at multiple critical analyte concentrations showed total imprecision of &amp;lt;3% and within-run imprecision of &amp;lt;3%. The Glucose serum assay demonstrated acceptable linearity throughout the 10-800 mg/dL analytical measuring range. Method comparison studies compared the DxC 500i analyzer against the AU480 and DxC 700 AU systems. A Weighted Deming regression of serum patient samples (n&amp;gt;100 measured across the analytical range) yielded a 0.986 slope, 0.227 mg/dL intercept, and R=0.9999 correlation coefficient against the DxC 700 AU and a 0.995 slope, 0.356 mg/dL intercept, and R=0.9999 correlation coefficient against the AU480. DxC 500i Immunoassay results: Cortisol (33600) Beckman Coutler’s Cortisol assay exhibited total imprecision of &amp;lt;12%CV at &amp;lt;5 μg/dL or &amp;lt;10CV% at ≥5 μg/dL for serum. The Cortisol assay demonstrated acceptable linearity throughout the 0.4-60 μg/dL analytical measuring range. A method comparison study compared the DxC 500i against the Access 2 system. A Weighted Deming regression of serum patient samples (n&amp;gt;100 measured across the analytical range) yielded a 0.9785 slope, 0.2764 μg/dL intercept, and R=0.9932 correlation coefficient. DxC 500i Carryover Assessment The Total βhCG (5th IS) assay was used to evaluate the potential of chemistry analyzer to immunoassay analyzer sample carryover. The study used High hCG serum samples (&amp;gt;1,000,000 mIU/mL) and Low hCG serum samples (4-6 mIU/mL). The DxC 500i exhibited a cumulative carryover of ≤2 parts per million (PPM) for serum. Conclusions These studies demonstrate excellent analytical performance for the new Beckman Coulter DxC 500i Clinical Analyzer* and confirm comparable performance to current Beckman Coulter standalone Clinical Chemistry and Immunoassay analyzers on the market. *Pending clearance by the United States Food and Drug Administration; not yet available for in vitro diagnostic use in the U.S. Product availability and regulatory status depends on country registration per applicable regulations.

Abstract Background Glial Fibrillary Acidic Protein (GFAP) levels are shown to be an indicator of neurologic injury in conditions like Traumatic Brain Injury (TBI) and stroke and as a marker of disease progression in neuromuscular disorders such as multiple sclerosis. Plasma GFAP is also implicated in detecting AD pathology, correlating to the clinical stage of the disease. The performance characteristics of the plasma GFAP immunoassay currently being developed on Beckman Coulter Access 2 and DxI 9000 analyzers are described. Methods The prototype GFAP assay is a one-step sandwich assay utilizing an anti-GFAP mouse monoclonal (MAb) antibody/alkaline phosphatase conjugate and paramagnetic particles coated with a complementary anti-GFAP mouse MAb. Sample and reactants are incubated and washed, and then a chemiluminescent substrate is added. The light generated is directly proportional to the GFAP concentration in the sample. The assay time to the first result is ∼30 minutes. Analytical performance evaluation and method comparison across different platforms was performed. 43 EDTA plasma samples, consisting of 19 Alzheimer’s Disease (AD) patient samples and 24 age-matched healthy normal samples, were evaluated. Results The prototype GFAP assay has a targeted analytical measuring range of 1.0 pg/ml to approximately 700.0 pg/ml (up to 10,000 pg/ml). All normal samples were quantified with 90% measuring below 20.0 pg/ml and a low dose coefficient of variation &amp;lt;4.0%. A comparison of the prototype GFAP assay on DxI 9000 and Access 2 analyzers shows a Passing-Bablok slope of 0.94 (R=0.992) and an intercept of 0.37 pg/ml. Concordance analysis shows excellent agreement between the Access 2 and DxI 9000 assays. The dose ratio of the median of AD over the median of normal samples for Access 2 and DxI 9000 is 2.31 and 2.41, respectively, with AD patient median dose values of 14.3 pg/ml and 14.6 pg/mL, respectively, and normal sample median dose values of 6.2 pg/ml and 6.0 pg/mL, respectively. Conclusions The prototype GFAP assay provides fast, highly sensitive, and precise results in an automated immunoassay on the Beckman Coulter Access 2 and DxI 9000 platforms. The prototype plasma GFAP assay holds promise for diagnosing and monitoring various neurodegenerative diseases, including AD.

Accurate antimicrobial susceptibility testing (AST) and reporting are essential for guiding appropriate therapy for patients and direction for public health prevention and control actions. A critical feature of AST reporting is the interpretation of AST results using clinical breakpoints for reporting as susceptible, susceptible-dose dependent, intermediate, or resistant. Breakpoints are subject to continuous adjustment and updating to best reflect current clinical data. These breakpoint changes can benefit patients and public health only if adopted in a timely manner. A recent survey identified that up to 70% of College of American Pathologists (CAP)-accredited U.S. laboratories and 45% of CAP-accredited laboratories outside the U.S. use various obsolete clinical breakpoints to interpret AST results to guide patient care. The reason for the ongoing use of obsolete breakpoints is multifactorial, including barriers encountered by laboratories, commercial AST device manufacturers, standards development organizations, and regulatory bodies alike. To begin to address this important patient safety issue, CAP implemented checklist requirements for CAP-accredited laboratories to ensure up-to-date clinical breakpoint use. Furthermore, the topic was discussed at the June 2022 American Society for Microbiology Clinical Microbiology Open (CMO) with various stakeholders to identify potential solutions. This minireview summarizes the breakpoint setting process in the U.S. and highlights solutions to close the gap between breakpoint revisions and implementation in clinical and public health laboratories. Solutions discussed include clarification of data requirements and minimum inhibitory concentration only reporting for regulatory clearance of AST devices, clinical data generation to close breakpoints gaps, advocacy, education, and greater dialogue between stakeholders.

To investigate how missing data in the patient problem list may impact racial disparities in the predictive performance of a machine learning (ML) model for emergency department (ED) triage. Racial disparities may exist in the missingness of EHR data (eg, systematic differences in access, testing, and/or treatment) that can impact model predictions across racialized patient groups. We use an ML model that predicts patients' risk for adverse events to produce triage-level recommendations, patterned after a clinical decision support tool deployed at multiple EDs. We compared the model's predictive performance on sets of observed (problem list data at the point of triage) versus manipulated (updated to the more complete problem list at the end of the encounter) test data. These differences were compared between Black and non-Hispanic White patient groups using multiple performance measures relevant to health equity. There were modest, but significant, changes in predictive performance comparing the observed to manipulated models across both Black and non-Hispanic White patient groups; c-statistic improvement ranged between 0.027 and 0.058. The manipulation produced no between-group differences in c-statistic by race. However, there were small between-group differences in other performance measures, with greater change for non-Hispanic White patients. Problem list missingness impacted model performance for both patient groups, with marginal differences detected by race. Further exploration is needed to examine how missingness may contribute to racial disparities in clinical model predictions across settings. The novel manipulation method demonstrated may aid future research.

Abstract Background Cefepime-taniborbactam is an investigational agent with activity against carbapenem and multidrug-resistant Enterobacterales and Pseudomonas aeruginosa.1 Given the need for accurate antimicrobial susceptibility testing results to support patient care decisions, a multicenter study was conducted with Enterobacterales and Pseudomonas aeruginosa clinical isolates on investigational MicroScan Dried Gram-negative MIC (MSDGN) panels with cefepime-taniborbactam.2 Materials/Methods MSDGN panels were evaluated at three clinical sites by comparing MIC values obtained using MSDGN panels to MICs utilizing CLSI broth microdilution reference panels. The study included 490/491 Enterobacterales and 65 Pseudomonas aeruginosa clinical isolates tested using Prompt® and turbidity methods of inoculation during the combined efficacy and challenge phases. MSDGN panels were incubated at 35 ± 1°C and read on the WalkAway System, the autoSCAN-4 instrument, and visually at 16–20 h. Frozen reference panels were prepared according to CLSI/ISO methodology, incubated for 16–20 h and read visually. Results Essential agreement was calculated compared to MIC results from frozen reference panels for isolates tested in efficacy and challenge and found in the following table. Conclusion Cefepime-taniborbactam MIC results for Enterobacterales and Pseudomonas aeruginosa obtained with the MSDGN panel correlate well with MICs obtained using frozen reference panels in this multicenter study.Pending approval by the US Food and Drug Administration; not available for in vitro diagnostic use in the US. Not for Distribution in the US.Pending submission and clearance by the US Food and Drug Administration; not yet available for in vitro diagnostic use in the US.For Investigational Use Only. Performance characteristics of this product have not been established.Read methodEnterobacterales Essential agreement (EA) % (n/N)Pseudomonas aeruginosaEssential agreement (EA) % (n/N)PromptTurbidityPromptTurbidityWalkAway90.0 (441/490)99.2 (487/491)100.0 (65/65)100.0 (65/65)autoSCAN-494.3 (462/490)99.0 (486/491)98.5 (64/65)98.5 (64/65)Visually92.7 (454/490)99.2 (487/491)100.0 (65/65)100.0 (65/65)Abbreviations: Prompt, Prompt inoculation method, Turbidity, Turbidity inoculation method.

Abstract Background Sepsis is the leading cause of in-hospital death. Outcome improvement requires rapid detection and early antimicrobial therapy. The complete blood count (CBC) is ordered for more than two-thirds of all patients in the emergency department (ED). Individual CBC components have limited utility for sepsis screening due to low specificity and sensitivity. We sought to create a reliable sepsis screening tool by combining components of the CBC differential. Methods In this single-center retrospective cohort study, all adult patients who had a CBC with differential performed within 6 h of ED arrival during a 20-month period were eligible for inclusion. Repeat ED visits by the same patient were excluded. Our primary outcome was manifestation of sepsis within 72 h of ED arrival, detected from timestamped electronic health records using a previously validated electronic phenotype based on Sepsis-3 consensus criteria. Multivariable logistic regression was performed to identify individual components of the CBC differential that were independently associated with our outcome and to identify optimal cutoffs for discretization. Odds ratios were used to assign weights to each component and to derive a 10-point system for scoring likelihood of sepsis. Results 34 864 patients were included; 1306 (3.7%) met sepsis outcome criteria within 72 h of ED arrival and 181 (0.5%) had septic shock. White blood cell (WBC) count, monocyte distribution width (MDW), and the neutrophil to lymphocyte count ratio were found to predict sepsis. As shown in the figure, there was a linear relationship between our CBC infection severity index and likelihood of developing sepsis and septic shock. Patients with a high risk score (8 or above) had a greater than one in four chance of developing sepsis within 72 h. Conclusion A simple ten-point index derived from the most commonly used laboratory panel in medicine reliably estimated likelihood of developing sepsis.