bluuebunny/crossref_metadata_2025 huggingface dataset:
The surface downward longwave radiation of the CMIP6 HighResMIP in East Asia offline corrected by the three-dimensional sub-grid terrain longwave radiative effect scheme
Authors: Gu Chunlei , Huang Anning , Li Xin , Wu Yang
Published: October 2024

Terrain significantly regulates surface downward longwave radiation (SDLR). The CMIP6 HighResMIP models without the three-dimensional sub-grid terrain longwave radiative effects (3DSTLRE) produce large SDLR biases over complex terrains. This study applies the 3DSTLRE scheme to correct the SDLR simulated by these models in East Asia and assesses the correction’s effectiveness. Results indicate that the CMIP6 HighResMIP models without the 3DSTLRE clearly underestimate the SDLR over the rugged terrains and the underestimation increases with the sub-grid terrain complexity. The offline correction of 3DSTLRE can evidently improve the SDLR simulations in different seasons, and the improvements increase with the sub-grid terrain complexity. The most significant improvements are observed over the Himalayas, the Tibetan Plateau, the Tianshan Mountains, and the Hengduan Mountains. The relative root mean square error of SDLR simulations over the areas with the most complex sub-grid terrains can be decreased by ∼40% due to the offline correction of 3DSTLRE. Considering the 3DSTLRE may be an efficient way to improve the simulations of the SDLR and surface energy balance over the regions with complex sub-grid terrains.
Application of SPNGO-VMD-SVM in rolling bearing fault diagnosis
Authors: Ni Wenjun , Zhang Chang , Li ShuangTian
Published: October 2024

Traditional bearing fault feature extraction and fault classification methods have low recognition accuracy and limited recognition capability in noisy environments. To address this problem, this paper proposes an improved Northern Goshawk Algorithm to optimize the variational modal decomposition (VMD) and support vector machine (SVM) to achieve bearing fault diagnosis. Firstly, to overcome the disadvantages of the Northern Goshawk Algorithm, such as easy fall into local optimal solutions and slow convergence speed, the Sine Cosine Strategy (SCA) and Position Optimisation Search Algorithm (POS) are introduced to optimize the Northern Goshawk Algorithm. The improved algorithm is called SPNGO for short. The superiority of the SPNGO algorithm is proved by comparing different algorithms. Then, SPNGO-VMD is used to adaptively decompose the vibration signals of faulty bearings and generate multiple modal components IMF. The effective IMF components are screened based on the craggy principle to reconstruct the signals. Finally, the reconstructed feature signals are input into SPNGO-SVM for fault classification and compared with other fault diagnosis models. The research results show that the proposed SPNGO-VMD-SVM fault diagnosis model is compared with the data set of Case Western Reserve University and the data set of Xi’an Jiaotong University. The diagnostic accuracy of the two groups of experiments can reach 96.67% and 98.89% respectively, and the intelligent diagnosis of different fault states of rolling bearings can be realized simultaneously.
Static and dynamic characteristics of electrostatically coupled MEMS beams under asymmetric actuation conditions
Authors: Shankar Uma , Bhushan Anand
Published: October 2024

Electrostatically actuated microbeams have gained prominence due to their applications as micro-actuators and ultrasensitive sensors. In this study, we investigate the dynamic behavior of electrostatically coupled microbeams, specifically focusing on the effects of asymmetric actuation conditions. Our investigation encompasses both static and dynamic characteristics of the coupled microbeam system, considering various gap ratios between the beams and the fixed electrodes. Within the coupled system, two doubly clamped microbeams are positioned between two fixed electrodes. We develop a reduced-order model (ROM) to investigate static and dynamic responses of the coupled system. To validate the ROM, we rigorously compare its results with finite element (FE) simulations. Our findings reveal that the gap ratios play a pivotal role in shaping the system’s response. Notably, first two natural frequencies are important for design of micro-resonators and they exhibit complex variation with respect to applied DC voltage. Moreover, we explore resonance frequency tunability and investigated interplay between geometric nonlinearity and nonlinear electrostatic actuation forces. These insights contribute significantly to the efficient design of MEMS resonators.
Research on high voltage circuit breaker multi-sensor signal feature selection method based on GA-Kmeans algorithm
Authors: Ma Suliang , Meng Zeqing , Shao Yang , Jiang Yuan , Xin Dixi
Published: October 2024

Currently, in the research on fault information of high-voltage circuit breakers (HVCBs) based on multi-sensor data, issues such as shallow feature assessment and unclear feature selection rules exist, leading to a decrease in fault identification accuracy due to redundant characteristics. To address this, this paper proposes a novel feature selection method based on GA-Kmeans. This method encodes the original feature space into binary format and employs the clustering accuracy of the Kmeans model as the fitness function to obtain a high-quality feature subset that maximally represents and distinguishes faults. By combining different feature selection methods with fault diagnosis models, six typical application scenarios are constructed. Results indicate that compared to traditional methods such as Relief-F, KPCA, GA-SVM for feature selection, and SVM for fault diagnosis, the proposed GA-Kmeans method reduces the dimensionality of the original feature space and employs the Kmeans clustering algorithm as the diagnostic model, achieving a final diagnostic accuracy of 95.29%. This method outperforms others, with a 37.24% higher diagnostic accuracy than SVM under the original feature space, and a decrease of 47.90% in standard deviation. This validates the necessity of feature selection and the superiority of the proposed method, providing a reliable and stable diagnostic basis for subsequent mechanical fault diagnosis of HVCBs.
IDEEA: information diffusion model for integrating gene expression and EEG data in identifying Alzheimer’s disease markers
Authors: Ozelbas Enes , Sevimoglu Tuba , Kahveci Tamer
Published: October 2024

Understanding the genetic components of Alzheimer’s disease (AD) via transcriptome analysis often necessitates the use of invasive methods. This work focuses on overcoming the difficulties associated with the invasive process of collecting brain tissue samples in order to measure and investigate the transcriptome behavior of AD. Our approach called IDEEA (Information Diffusion model for integrating gene Expression and EEG data in identifying Alzheimer’s disease markers) involves systematically linking two different but complementary modalities: transcriptomics and electroencephalogram (EEG) data. We preprocess these two data types by calculating the spectral and transcriptional sample distances, over 11 brain regions encompassing 6 distinct frequency bands. Subsequently, we employ a genetic algorithm approach to integrate the distinct features of the preprocessed data. Our experimental results show that IDEEA converges rapidly to local optima gene subsets, in fewer than 250 iterations. Our algorithm identifies novel genes along with genes that have previously been linked to AD. It is also capable of detecting genes with transcription patterns specific to individual EEG bands as well as those with common patterns among bands. In particular, the alpha2 (10–13 Hz) frequency band yielded 8 AD-associated genes out of the top 100 most frequently selected genes by our algorithm, with a p-value of 0.05. Our method not only identifies AD-related genes but also genes that interact with AD genes in terms of transcription regulation. We evaluated various aspects of our approach, including the genetic algorithm performance, band-pair association and gene interaction topology. Our approach reveals AD-relevant genes with transcription patterns inferred from EEG alone, across various frequency bands, avoiding the risky brain tissue collection process. This is a significant advancement toward the early identification of AD using non-invasive EEG recordings.
Functoriality in categorical symplectic geometry
Authors: Abouzaid Mohammed , Bottman Nathaniel
Published: October 2024

Categorical symplectic geometry is the study of a rich collection of invariants of symplectic manifolds, including the Fukaya

A
∞

A_\infty

-category, Floer cohomology, and symplectic cohomology. Beginning with work of Wehrheim and Woodward in the late 2000s, several authors have developed techniques for functorial manipulation of these invariants. We survey these functorial structures, including Wehrheim and Woodward’s quilted Floer cohomology and functors associated to Lagrangian correspondences, Fukaya’s alternate approach to defining functors between Fukaya

A
∞

A_\infty

-categories, and the second author’s ongoing construction of the symplectic

(

A
∞

,
2
)

(A_\infty ,2)

-category. In the last section, we describe a number of direct and indirect applications of this circle of ideas, and propose a conjectural version of the Barr–Beck monadicity criterion in the context of the Fukaya

A
∞

A_\infty

-category.
Algebraic solutions of linear differential equations: An arithmetic approach
Authors: Bostan Alin , Caruso Xavier , Roques Julien
Published: October 2024

Given a linear differential equation with coefficients in

Q

(
x
)

\mathbb {Q}(x)

, an important question is to know whether its full space of solutions consists of algebraic functions, or at least if one of its specific solutions is algebraic. After presenting motivating examples coming from various branches of mathematics, we advertise in an elementary way a beautiful local-global arithmetic approach to these questions, initiated by Grothendieck in the late sixties. This approach has deep ramifications and leads to the still unsolved Grothendieck–Katz

p
p

-curvature conjecture.
Feasibility and acceptability of the HOLObalance telerehabilitation system compared with standard care for older adults at risk of falls: the HOLOBalance assessor blinded pilot randomised controlled study
Authors: Pavlou Marousa , Flavell Carol Ann , Gourtani Fariba Mostajeran , Nikitas Christos , Kikidis Dimitris , Bibas Athanasios , Gatsios Dimitris , Tsakanikas Vassilis , Fotiadis Dimitrios I , Koutsouris Dimitrios , Steinicke Frank , Walz Isabelle Daniela , Maurer Christoph , Papadopoulou Sofia , Tsoukatos Michalis , Pardalis Athanasios , Bamiou Doris-Eva
Published: October 2024

Background

Falls have high socioeconomic costs. Information and communication technologies may support provision and monitoring of multisensory (MSR) physiotherapy programmes. The HOLOBalance platform used augmented reality holograms to provide patient-centred, individualised MSR.

Objectives

To determine the platform’s safety, acceptability and feasibility, investigate functional gait and dynamic balance benefits and provide data for a definitive trial.

Design and setting

Single-blinded pilot randomised controlled feasibility study. Interventions were conducted at clinical sites or participants’ homes in three European countries.

Participants

Community-dwelling older adults (median age 73 years; 64.2% female) at risk of falls were enrolled (May 2020-August 2021).

Methods

Participants were randomised to an 8-week clinic or home-based telerehabilitation MSR or OTAGO (control group) programme. Compliance, satisfaction, and adverse events determined feasibility. Clinical outcomes, assessed (blinded) within one-week prior to and post-intervention, included functional gait assessment (FGA), Mini BESTest and cognitive function.

Results

Randomisation to completion rate was 76.15% with 109 participants recruited (n = 289 screened). Drop-out rate was similar between groups. Adverse events were reported (n = 3) in the control group. Sixty-nine percent would recommend the HOLOBalance intervention. Findings were similar for the home and clinic-based arms of each intervention; data was combined for analysis. FGA (95%CI [1.63, 4.19]) and Mini-BESTest (95%CI [1.46, 3.93]) showed greater improvement in the HOLOBalance group with a clinically meaningful change of 4/30 noted for the FGA.

Conclusions

HOLObalance was feasible to implement and acceptable to older adults at risk of falls, with FGA and Mini-BEST improvements exceeding those for the OTAGO programme. A definitive trial is warranted.
Recover then aggregate: unified cross-modal deep clustering with global structural information for single-cell data
Authors: Wang Ziyi , Luo Peng , Xiao Mingming , Wang Boyang , Liu Tianyu , Sun Xiangyu
Published: October 2024

Single-cell cross-modal joint clustering has been extensively utilized to investigate the tumor microenvironment. Although numerous approaches have been suggested, accurate clustering remains the main challenge. First, the gene expression matrix frequently contains numerous missing values due to measurement limitations. The majority of existing clustering methods treat it as a typical multi-modal dataset without further processing. Few methods conduct recovery before clustering and do not sufficiently engage with the underlying research, leading to suboptimal outcomes. Additionally, the existing cross-modal information fusion strategy does not ensure consistency of representations across different modes, potentially leading to the integration of conflicting information, which could degrade performance. To address these challenges, we propose the ’Recover then Aggregate’ strategy and introduce the Unified Cross-Modal Deep Clustering model. Specifically, we have developed a data augmentation technique based on neighborhood similarity, iteratively imposing rank constraints on the Laplacian matrix, thus updating the similarity matrix and recovering dropout events. Concurrently, we integrate cross-modal features and employ contrastive learning to align modality-specific representations with consistent ones, enhancing the effective integration of diverse modal information. Comprehensive experiments on five real-world multi-modal datasets have demonstrated this method’s superior effectiveness in single-cell clustering tasks.
A-053 Evaluation of the Analytical Performance of Atellica CH Prealbumin and β2-Microglobulin Chemistry Assays on the Atellica CI Analyzer
Authors: Huff J , Varhue W , Gupta P , Shalhoub V , Camacho J , Snyder J
Published: October 2024

Background

The Atellica® CI Analyzer is an automated, mid-throughput, integrated chemistry and immunoassay analyzer utilizing both Atellica® CH and Atellica® IM assays. This study was designed to evaluate the analytical performance of the Atellica® CH Prealbumin (PALB) and β2-Microglobulin (B2M) Assays on the Atellica CI Analyzer.

Methods

The Atellica CI PALB and B2M assays use the same reagents and calibrators as the Atellica CH assays. Precision and method comparison (MC) were used as performance indicators for the Atellica CI Analyzer. Precision studies were performed according to CLSI EP05-A3 using native, QC, and contrived human serum samples. One aliquot of each sample pool was tested in duplicate in two runs per day >2 hours apart on each analyzer for 20 days. Method comparison (MC) studies were performed per CLSI EP09-A3. Individual serum samples were analyzed using the Atellica CH and Atellica CI Analyzers. Linearity and verification of detection capability studies were demonstrated for both assays.

Results

Representative precision, and MC results are presented in the table. Over the two assays tested, repeatability and within-lab %CVs were <4.0% and <4.6%, respectively. Slopes determined using the Deming linear regression model were approximately equal to 1. The Atellica CH PALB assay is linear from 3.0-70.0 mg/dL (30-700 mg/L); LoB, 1.1 mg/dL (11 mg/L); LoD. 1.9 mg/dL (19 mg/L); LoQ, 3.0 mg/dL (30 mg/L). The Atellica CH B2M assay is linear from 0.25-18.00 mg/L; LoB, 0.10 mg/L; LoD, 0.20 mg/L.

Conclusions

Atellica CH PALB and B2M Assays on the Atellica CI Analyzer demonstrated good precision and equivalent performance to the same assays on the Atellica CH Analyzer.
A-080 Morning Cortisol for Rule-in and Rule-out of Adrenal Insufficiency in an Asian Population
Authors: Li B V , Lee A K , Hawkins R C
Published: October 2024

Background

Short ACTH stimulation (Synacthen) tests are performed to investigate for adrenal insufficiency. Previous work suggests that morning cortisol concentrations can be used to rule in or out adrenal insufficiency to avoid performance of a Synacthen test.

This study aimed to determine the optimal cortisol concentration for rule-in or rule-out adrenal insufficiency based on 30-minute cortisol (COR30) for adequate response using the assay-specific cut-off from The Endocrine Society of Australia/The Australasian Association for Clinical Biochemistry and Laboratory Medicine/The Royal College of Pathologists of Australasia (ESA/AACB/RCPA) Harmonization of Endocrine Dynamic Testing - Adult (HEDTA), in an Asian population.

Methods

Synacthen tests performed at our institution from 2012-2024, with a baseline cortisol between 6 and 10 am (COR0(6-10)), were extracted from the laboratory database. Plasma cortisol concentrations were measured by Beckman Coulter DxI 800. Synacthen tests were classified as adequate or inadequate based on the Beckman Coulter specific HEDTA cut-off for COR30 of 420 nmol/L. Performance characteristics (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under receiver operator characteristic (AUROC) curve) of COR0(6-10) concentrations to predict adequate or inadequate response were calculated using Microsoft Excel.

Results

4609 Synacthen tests were included, 77% of which had adequate Synacthen response. COR0(6-10) >300 nmol/L could exclude inadequate COR30 response with sensitivity 95%, specificity 48%, PPV 35%, NPV 97%; and COR0(6-10) >364 nmol/L had sensitivity 99%, specificity 29%, PPV 29%, NPV 99%. COR0(6-10) <155 nmol/L could rule-in inadequate COR30 response with sensitivity 53%, specificity 95%, PPV 76%, NPV 87%; and COR0(6-10) <97 nmol/L had sensitivity 35%, specificity 99%, PPV 91%, NPV 84%. AUROC of COR0(6-10) for adequate COR30 response was 0.86. If patients with COR0(6-10) <97 nmol/L and >300 nmol/L did not proceed to Synacthen testing, up to 46% of tests could be avoided, while keeping misclassification under 5%.

Conclusions

Morning cortisol cut-offs were determined for rule-in and rule-out of adrenal insufficiency in an Asian population. Patients with morning cortisol >300 nmol/L or <97 nmol/L may be able to avoid Synacthen testing unless there is a strong suspicion of clinical discordance. Such a testing strategy could significantly decrease the number of Synacthen tests while keeping misclassification to a minimum.
A-085 Comparing CO2 stability in patient samples and proficiency testing material
Authors: Bolte K , Matthews J , Patel K , Poventud-Fuentes I
Published: October 2024

Background

Total carbon dioxide (tCO2) measurements are important in the assessment of acid-base disorders. The collection and storage conditions of specimens are important preanalytical factors that can influence the accuracy of tCO2 measurements. Proficiency testing (PT) materials are used to assess the accuracy and reliability of a laboratory’s test performance. Unsuccessful performance on PT challenges can be an indicator of procedural issues. However, the stability of tCO2 in PT material compared to physiologic specimens is unknown and no guidance is provided to laboratories on how to handle PT samples for tCO2 measurement. This study aims to compare tCO2 stability in PT material with that of plasma samples when exposed to ambient air at room temperature.

Methods

Using enzymatic endpoint measurement on Vitros 4600 Chemistry System, tCO2 was measured in PT material (n = 5) and patient samples (n = 6) at baseline and after exposure to air for 15, 30, 60, 90, and 120 minutes. 500μL of each sample was aliquoted into EZ-nest tube adapters and baseline measurements were immediately analyzed. Average percent difference from baseline was calculated and >-10% bias was considered acceptable.

Results

The average percent difference from baseline in PT samples exceeded -10% as early as 30 minutes; whereas -3% bias was observed in patient samples at 60 minutes. Results are summarized in the table below.

Conclusions

The assessment of tCO2 stability ensures the reliability of laboratory measurements. Our results indicate tCO2 in PT material is not stable when exposed to air beyond 15 minutes, however tCO2 in most patient samples remained stable beyond 120 minutes. Understanding the stability limits of tCO2 in PT material allows us to devise workflows that prevent sample degradation during PT events. By establishing best practices for maintaining tCO2 integrity in PT material, laboratories can enhance the accuracy of proficiency testing results.
A-108 Re-evaluation of reference intervals for circulating albumin, total calcium, and magnesium levels among subjects in Dallas County
Authors: Hashim I , Agha A
Published: October 2024

Background

Reference intervals are either directly established from normal volunteers, adopted from assay manufactures and verified as transferable to the normal population, or indirectly derived using patients’ archived laboratory data. This study describes indirect derivation of reference intervals for albumin, total calcium, and magnesium appropriate to the patient population of Dallas County. The tests were selected due to their often combine measurement in the assessment of calcium and bone mineral metabolism

Methods

Retrospective reported laboratory results during May 2022 for albumin (n=1342), total calcium (n=1945), and magnesium (n=2148) were obtained. Values were subjected to statistical analysis for nature of distribution, mean, and standard deviation as well as stratified for patients’ characteristics (gender, race, and age). Statistical analysis applied were Hoffman regression analysis, one-way ANOVA, and Tukey-Kramer tests.

Results

Following removal of outliers, statistically suggested reference intervals for albumin, total calcium, and magnesium were 5.5 to 2.4 g/dL, 10.5 to 7.5 mg/dL, and 2.6 to 1.6 mg/dL respectively. Although there was race specific differences in albumin and calcium levels (p=0.032) and (p=0.002) respectively, differences for magnesium were slightly nonsignificant (p=0.06). Similarly, significant differences due to age were observed for albumin, total calcium, and magnesium (P <0.00 for all). The data suggests that albumin, magnesium, and calcium levels are unequivocally dependent on age and race for patients in Dallas County. The upper limits of population derived, and manufacturer verified reference intervals were 5.45 and 5.2 g/dL for albumin, 10.5 and 10.2 mg/dL for calcium, and 4.6, and 2.6 mg/dL for magnesium respectively, the lower limits were 2.4 and 3.5, 7.5 and 8.4, 1.4, and 1.6 mg/dL respectively.

Conclusions

Reference intervals for albumin, total calcium, and magnesium appropriate to the patient population of Dallas County were derived. Derived values were statistically different from the manufacturer verified values in use. The study although limited by the small number of acceptable samples, highlights the need for laboratories to derive their respective population-based reference intervals. The study will be expanded to other biochemical parameters utilizing much larger sample volume.
A-131 An External Laboratory Validation of the Atellica IM Serum Neurofilament Light Chain Assay
Authors: Abou-Diwan C , Shields M , Miller A , Kissel J , Nalayanda D , Troksa E , Shields A
Published: October 2024

Background

Neurofilament light chain (NfL) in serum is a promising biomarker for axonal injury with potential for use in neurodegenerative disease testing, including multiple sclerosis (MS), Alzheimer’s disease, and amyotrophic lateral sclerosis (ALS). This study validated the Siemens Healthineers Atellica® IM Serum Neurofilament Light Chain (sNfL) assay* for research applications.

Methods

Precision studies were performed using serum and plasma samples. Intra-assay precision comprised three levels of internal assay quality control (QC) and one plasma or serum pool (consisting of serum spiked with CSF). For plasma, one aliquot of each sample was tested in duplicate in two runs per day >2 hours apart for up to >20 days. Serum inter-assay involved three levels of internal assay QC run over 10 days (1 run/day). Sensitivity studies were performed to evaluate the limit of quantitation (LoQ) for serum and plasma using five low concentration samples. Each concentration was tested in 25 replicates for serum, and 50 replicates for plasma. Linearity studies involved five levels, each run three times in duplicate (plasma) or four times (serum). Method comparison studies were performed according to CLSI EP09-A3 using the Atellica® IM NfL laboratory developed test (LDT) offered by Siemens Healthcare Laboratory, LLC. 50 samples within the measuring interval of the LDT for each sample type (plasma and serum) were tested.

Results

Intra-assay coefficients of variation (%CVs) for internal QC ranged from 1.7-2.5% for concentrations spanning 12.75 to 147.22 pg/mL. Serum and plasma pool intra-assay %CV were 2.5% and 3.4%, respectively. Inter-assay precision of serum %CVs ranged from 2.9-16.1% for 13.4 to 150.8 pg/mL. Plasma inter-assay %CVs demonstrated a slightly improved precision versus serum across runs with %CV ranging from 2.4-12.8% with plasma concentrations ranging from 13.4 to 158.0 pg/mL. Serum and plasma LoQs, defined as the concentration at which CV is <20%, were 2.5 pg/mL (serum/plasma). The assay was linear between 2.5 to 300 pg/mL for serum and plasma. The Atellica IM sNfL assay method comparison to the Atellica IM NfL LDT was analyzed using a Passing-Bablok linear regression model. The assays exhibited acceptable agreement with slopes in the range of 1.12-1.14 across the sample interval tested, 6.4 to 460 pg/mL for serum/plasma.

Conclusions

This external validation of the Atellica IM sNfL assay demonstrated performance characteristics suitable for research applications.

*For Research Use Only. Not for use in diagnostic procedures.
A-136 Icteric Interference is not Resolved with Sample Dilution in Serum Creatinine and Total Protein Assays
Authors: Zakrajsek J T , Zakrajsek J A , Spiesman A M , McShane A J
Published: October 2024

Background

Icterus is a common endogenous interference that can cause falsely low results for serum creatinine and total protein. It can be defined by elevated unconjugated (indirect) and conjugated (direct) bilirubin levels and is most commonly associated with liver dysfunction. Recent literature suggests that dilutions can be a reliable method to reduce bilirubin interference. The purpose of this study was to determine whether the vendor’s on-board sample dilution can eliminate icteric interference with creatinine and total protein.

Methods

Creatinine (enzymatic) and total protein interference studies were performed on an automated chemistry analyzer (Roche Diagnostics, cobas c702). Low, mid, and high sample pools for each analyte were divided into four equal volumes. To achieve an icterus index (II) of approximately 40 (approximately 40 mg/dL of bilirubin), one sample pool was spiked with unconjugated bilirubin, and one pool was spiked with conjugated bilirubin. An equal amount of diluent was added into each control pool and remained at an II of approximately 0. The icteric and control samples were measured for conjugated and unconjugated bilirubin, serum indices, and the target analyte. Using the on-board dilution function, the icteric creatinine and total protein pools were diluted using a 1:4 and 1:3 dilution, respectively. All samples were analyzed in triplicate. Percent variance was found by calculating the difference between the average dilution result and control result and then dividing by the average control result.

Results

Conclusions

Only modest alleviation of icteric interference was noted with dilution. The average bias was 10% for creatinine and 24% with total protein, after dilution. The on-board sample dilution is not effective in eliminating icteric interference when measuring both creatinine and total protein.
A-165 Value Of Monocyte Distribution Width In Bacteremia Assessment In Emergency Department Patients
Authors: Cook B , Jaehne A K , Naiman M , Wilson I , Veryser D , Kelly W , Ghosh S , Rivers E
Published: October 2024

Background

Monocyte distribution width (MDW) is an immune response biomarker and part of a CBC differential. MDW is derived from the distribution of monocyte volumes and elevated MDW values correlate with severe infections and sepsis in Emergency Department (ED) adult patients. Neutrophil to lymphocyte ratio (NLR) is predictive of infections and inflammatory stress. Evaluating these biomarkers could be valuable in bacteremia risk assessment. Bacteremia is the presence of viable bacteria in the bloodstream and is present in up to 20% of septic patients. Blood cultures establish pathogen identity but require culture time, potentially delaying appropriate treatment. Our goal was to characterize MDW and NLR clinical performance in ED patients with suspected bacteremia.

Methods

This was an observational cohort study of ED patients 18 years and older with CBC differential and blood cultures obtained. MDW values ≥20 is the published cut-off for increased infection risk. Clinical literature suggests that NLR ≥3 is abnormal. We assessed the diagnostic performance of MDW and NLR for positive blood cultures using SPSS Version 25.

Results

From 07/2021-09/2023, 9,400 blood cultures were ordered and 5174 patients had differential CBCs. The overall blood culture positivity rate was 14.4%. MDW and NLR performance for positive blood cultures is shown in Table 1.

Conclusions

Our analysis provides evidence that MDW and NLR may be useful for early recognition of bacteremia in ED patients. CBC differential results are reported sooner than culture results. MDW is directly reported, NLR can be readily calculated from the differential. Therefore both could contribute to earlier risk stratification and our findings suggest potentially distinct information from MDW and NLR. Combining MDW with other CBC parameters may provide additional diagnostic advantage. Further analysis will incorporate added clinical data for enhanced decision support in interpreting MDW values in the context of pending blood culture results.
A-249 Monocyte distribution width (MDW) as a reliable diagnostic biomarker for sepsis in HIV-infected patients
Authors: Sun J , Shao Y , Qian L , Wang X , Tang Y , Lu H , Chen J
Published: October 2024

Background

Sepsis is the main cause of death in patients with acquired immunodeficiency syndrome (AIDS) and early diagnosis of sepsis in AIDS remains a significant challenge. Monocyte distribution width (MDW), as a new type of sepsis auxiliary diagnostic marker, has attracted widespread attention in the research and exploration of its clinical application. This study aims to evaluate the diagnostic efficacy of MDW in the occurrence of sepsis in HIV-infected patients and to construct a new clinical diagnostic model in combination MDW with other indicators.

Methods

A prospective cohort study was conducted at Shanghai Public Health Center with a total of 602 patients enrolled between December 2022 and August 2023. Sepsis-3 criteria were employed as the diagnostic standard for sepsis. MDW was measured at admission, using the hematology analyzer DxH900 (Beckman Coulter Inc.). Comprehensive clinical data, including complete blood counts and biochemical profiles, were collected. Enrolled participants received a follow-up about their survivals on day 30 and day 90. Five machine learning models were evaluated and compared to select the best performing model.

Results

The diagnostic performance of MDW for sepsis yielded an AUC of 0.818. With a cut-off value of 25.26, the sensitivity and specificity reached 0.822 and 0.754 respectively. The best performing variable among all five ML algorithms was Random Forest model. The top three variables with the highest importance ranking were platelet, albumin, and hemoglobin. Incorporating MDW and the top three laboratory indicators into a random forest model, the AUC value improved to 0.931. With a cut-off value of 0.5, the sensitivity was 1.00 while the specificity was 0.732.

Conclusions

MDW was an auxiliary diagnostic biomarker for sepsis in HIV-infected patients with reliable sensitivity and specificity. In combination MDW with other common laboratory biomarkers, a diagnostic model can be established to further improve the diagnostic efficiency of sepsis.
A-292 Validation of Aztreonam-Avibactam MIC Antimicrobial Susceptibility Test for MicroScan Dried Gram-Negative MIC Panels from a Multicenter Assessment of Enterobacterales, Pseudomonas species, and Stenotrophomonas maltophilia
Authors: Diaz J E , Garner O , Harrington A , DesJarlais S , Riedel S , Chipman A , Guzman B M , Hastey C
Published: October 2024

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
A-341 Precision Evaluation of the i-STAT® Glucose Test in the i-STAT G Cartridge using thei-STAT 1 System for Venous, Arterial and Capillary Whole Blood Specimens in Clinical Settings
Authors: Thibodeau L , Gonzalez Aguirre M , Hahn S , Zhang H
Published: October 2024

Background

Precise and accurate measurements of whole blood glucose levels are important for the diagnosis and treatment of patients suffering from diabetes and hypoglycemia. This study demonstrates the precision of the i-STAT G cartridge with the i-STAT 1 System in arterial, venous, or capillary whole blood in point of care or clinical laboratory settings.

Methods

The precision of the i-STAT G cartridge was assessed at external clinical sites by intended end users with whole blood specimens across the measurement range of 20 - 700 mg/dL. The study included testing venous whole blood samples from 154 adult (≥ 18 years) patients and arterial whole blood samples from 173 adult patients at three clinical sites. Each whole blood sample was run in duplicate on the i-STAT G cartridge. In addition, 139 capillary whole blood specimens from both adult subjects and neonate subjects (birth - 28 days) were collected and tested for capillary whole blood precision. Duplicate fingerstick draws were collected in capillary tubes from 119 adult subjects at two clinical sites and duplicate heel-stick specimens were collected in capillary tubes from 20 neonate subjects at two clinical sites. Specimens used in this study were prospectively collected venous, arterial, or capillary specimens under an Institutional Review Board approved informed consent or were de-identified leftover venous or arterial specimens. For each specimen type, duplicates from each subject were grouped into subintervals based on their mean values. The subintervals included the glucose medical decision levels of 45 mg/dL, 120 mg/dL and 180 mg/dL. The estimates of the pooled standard deviation (SD) and pooled coefficient of variation (%CV), as well as their respective 95% confidence intervals (CI) were calculated for each subinterval (20-90 mg/dL, >90-150 mg/dL, >150-250 mg/dL, >250-700 mg/dL or >250-400 mg/dL and >400-700 mg/dL, as applicable). The precision estimates for each subinterval were compared against an acceptance criteria of the greater of 3 mg/dL or 5% of the mean (mg/dL) of the subinterval.

Results

The whole blood precision was found to be less than or equal to 5.00 %CV for all subintervals for each specimen type. For venous specimens, the %CV ranged from 0.35% to 0.43%; for arterial specimens the %CV ranged from 0.26% to 0.46% and for capillary specimens (adult and neonate combined), the %CV ranged from 1.38% to 2.71%.

Conclusions

The study demonstrated that the i-STAT Glucose test in the i-STAT G cartridge when tested using the i-STAT 1 System delivers precise results within ∼2 minutes for venous, arterial, and capillary whole blood patient specimens across a glucose range of 20 - 700 mg/dL when tested by end users in a point of care or clinical laboratory setting. The studies were funded by Abbott Laboratories.
B-032 Evaluation of Assay Performance for Atellica CI 1900 analyzer in Routine Chemistry, Division of Laboratory Medicine, UMMC
Authors: Yeoh A C , Ramdzan K , Jamaluddin F A , Chew Y Y
Published: October 2024

Background

The Atellica® CI 1900 (Siemens Healthiness) is a stand-alone, integrated clinical chemistry and immunoassay analyzer. Method verification has been done on this analyzer for 14 parameters based on the guideline of the Clinical and Laboratory Standard Institute (CLSI).

Methods

The method evaluation protocol consisted of determination of imprecision based CLSI EP 15-A3; CLSI EP06-A2 protocol was used for verification of linearity and method comparison was carry out in between Atellica® CI 1900 with our current Atellica® Solution based on CLSI EP09-A2 protocol. Method comparison data was analyzed by using statistical software, MedCalc. The data were used to calculate bias for Sigma metrics determination.

Results

Total of 14 analytes including sodium, potassium, chloride, creatinine, urea, alkaline phosphatase, total bilirubin, triglyceride, uric acid, glucose, thyroid stimulating hormone, free-thyroxine, human chorionic gonadotropin and carcinoembryonic antigen were tested. The results showed the repeatability and total imprecision were within acceptable limit as per manufacturer claims for all analytes. It was demonstrated that the analytical system operates within the claimed linearity ranges as stated in the information for use (IFU). Passing - Bablok analysis show the bias for all analytes were within our laboratory pre-set quality specification. The intercept and slope with 95% CI for Passing-Bablok analysis as shown in table 1. Sigma metrics were determined for each assay using the coefficient variation determined from precision study and bias obtained from the method comparison study. It showed that the Sigma for 14 analytes ranging from 3 to more than 6 with more than 93% assay has sigma scores more than 4.

Conclusions

Atellica® CI 1900 shows acceptable precision and bias for all analytes that evaluated. The analyser is fully comparable with Atellica® Solution. We conclude that Atellica® CI 1900 demonstrates good performance capabilities, making this analyzer suitable for low-to-medium volume laboratory.
B-077 F-actin as a New Marker Antigen on an Established Multiparametric Immunoassay Profile for Liver Diseases
Authors: Weiss J , Deerberg A , Ott A , Kai M , Scheper T , Meyer W
Published: October 2024

Background

Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) are severe diseases with heterogenous manifestations, which affect people of all populations and age groups. Diagnosis and differentiation from other liver diseases such as primary sclerosing cholangitis (PSC) remain a substantial challenge for hepatologists. Since AIH and PBC are caused by different sets of autoantibodies, we previously developed a line blot for the parallel detection of all relevant parameters. We now added the AIH-specific antigen filamentous actin (F-actin) to this established liver immunoassay profile.

Methods

Sera from 15 patients with AIH, 15 patients with overlap AIH/PBC or AIH/PSC, 32 patients with PSC, 53 patients with PBC, 4 patients with non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH), 30 patients with hepatitis B infection and 79 patients with hepatitis C infection as well as sera from 150 blood donors were examined using the EUROLINE line immunoassay system (EUROIMMUN autoimmune liver diseases 9 Ag plus F-actin (IgG); contains the PBC-relevant antigens AMA-M2, M2-3E (BPO), Sp100, PML and gp210, the AIH-associated antigens LKM-1, LC-1 and SLA/LP and F-actin as well as Ro52). The newly included F-actin antigen was polymerized from human globular actin (G-actin) and assessed by sedimentation analysis and dynamic light scattering. The scan software EUROLineScan (EUROIMMUN) was used to automatically determine presence and intensity of the resulting bands on the blot.

Results

Quality assessment revealed successful polymerization of F-actin. Autoantibodies against this newly developed F-actin antigen were detected in 53.3% of sera from AIH patients and 40% of AIH+PBC/AIH+PSC overlap patients. 93% of these positive sera did not contain other autoantibodies associated with AIH. Only one PSC patient (3.1%), two patients with hepatitis C (2.5%) and two blood donors (1.3%) also showed anti-F-actin positivity. All tested sera of PBC, NAFLD/NASH and hepatitis B patients were evaluated as anti-F-actin negative.

Conclusions

The addition of F-actin to the established multiparametric EUROLINE profile for the simultaneous and monospecific detection of AIH- and PBC-relevant autoantibodies is a great advance for routine diagnostics of patients with symptoms associated with various liver diseases.
B-117 Rapid Classification of Cleanliness Grades of Vaginal Discharge through Computational Analysis of SERS Spectra via Variational Auto-Encoder Model And Long Short-Term Memory Networks
Authors: Wang L , Tang J
Published: October 2024

Background

Classification of cleanliness grades of vaginal discharge plays a pivotal role in clinical laboratories, serving as indicators for the presence of various vaginal infections such as bacterial vaginosis and candidal vulvovaginitis, etc. The conventional method for assessing vaginal discharge cleanliness involves manual microscopy, a technique susceptible to variations based on the examiner's expertise and subjective judgment, hindering the attainment of swift and accurate diagnoses.

Methods

This study introduces a novel approach by integrating Surface-Enhanced Raman Spectroscopy (SERS) with a deep learning algorithm for the rapid classification of vaginal discharge cleanliness grades. The proposed classification method combines the Variational Auto-Encoder (VAE) and Long Short-Term Memory (LSTM) to process SERS spectra. The quality of the training data is assessed using the signal-to-noise ratio (SNR) as a standard indicator.

Results

The application of the VAE-LSTM algorithm significantly enhances classification performance, providing swift and accurate results while reducing the required time. Comparative analyses with various classical machine learning algorithms and evaluation metrics reveal the superior predictive capability and time efficiency of the VAE-LSTM algorithm, demonstrating 100% accuracy and a fitting time of 2 seconds. Blind testing of SERS spectra collected from unknown patients further validates the reliability of the proposed method.

Conclusions

This study presents a promising and practical approach for the rapid classification of vaginal discharge cleanliness grades. The integration of the SERS technique with the VAE-LSTM algorithm not only ensures accuracy and efficiency in clinical diagnosis but also lays the foundation for advancements in non-invasive diagnostic technologies in gynecological healthcare.
B-225 Bridging the Gap Between Clinical Microbiology and Molecular Diagnostics: Correlation of PCR Cycle Threshold Values for Establishing Semi-Quantitative CFU/mL Ranges of Bacterial Targets
Authors: Griffith-Vandi J , Valdez A , Rahimian P , Wagenman B
Published: October 2024

Background

Molecular diagnostics (MolDx) has surpassed culture in the clinical microbiology laboratory. Wong (2023) states PCR is more sensitive than urine culture in detecting polymicrobial infections (para. 8), marking an advantage in MolDX for urinary tract infections. This advancement poses a challenge for clinicians in treatment decision-making. To address requests for numerical MolDx result ranges, a validation accessed semi-quantitative Colony Forming Units per milliliter (CFU/mL) through the assessment of PCR cycle threshold (CT) values.

Methods

Bacterial targets of UTI and STI PCR panels were inoculated in nutrient broth (Hardy diagnostics cat#K43) and incubated overnight in a shaking incubator at 35±2°C. The density of the cultures was measured using the OD600 function of a NanoDrop One/One after 18-24 hour incubation. The density of stock cultures was adjusted to 106 CFU/mL. Serial dilutions of stock were made in 1:10 steps covering the range of 106 to 100 CFU/mL. The stock and dilutions were extracted, and PCR was performed in a minimum of 2 replicates of each sample for the UTI and STI PCR panels. Mean CT values, standard deviations and coefficients of variation were calculated for each sample. The linearity of CT values within each organism’s stock and dilution samples were assessed by evaluating the CT differences between each dilution step. Corresponding CFU/mL concentrations were tabulated against each mean CT value.

Results

The average CT values for reportable CFU/mL ranges were established for each stock and dilution. Mean CT values for each CFU/mL breakdown across all organisms were also calculated, along with standard deviations, to investigate universal CT-CFU/mL correlations. A final interpretation table (Table 1) was constructed according to the universal range calculations.

Conclusions

The study confirmed correlation between CT values and CFU/mL ranges. Further data analysis and comparison with other laboratories’ results will enhance accuracy and precision of reportable CFU/mL ranges.