bluuebunny/crossref_metadata_2025 huggingface dataset:
A-222 Comparative Analysis of Clinical and Laboratory Parameters of Brazilian Patients with Severe Hipertriglyceridemia
Authors: Costa C L , Castelo M C , Veras V R , Ramos L T , Fernandes V O , Lima R S , Vasconcelos M P , Lima G P , Araujo J S , Montenegro A D , Queiroz L L , Ponte C M , Flor A C , Melo I D , Lopes A C , Montenegro R M
Published: September 2023

Background

The presence of elevated and sustained levels of triglycerides (TG) should raise the suspicion of primary causes of hypertriglyceridemia (HT), in which related genetic mutations would be identified. Thus, the aim of this study was to compare clinical and laboratory parameters of Brazilian patients with different etiologies of severe hypertriglyceridemia.

Methods

All patients with severe HT (considered as detection of TG above 880 mg/dL on at least 2 occasions) followed in the dyslipidemia outpatient clinic of Federal University of Ceará/Brazil, whose molecular study to investigate genetic variants potentially related to hypertriglyceridemia and pancreatitis has been previously performed (ABCA1 AGPAT2 AKT2 APOA5 APOC2 BSCL2 CAV1 CFTR CIDEC CTRC CYP27A1 GPIHBP1 LIPA LIPE LMF1 LMNA LMNB2 LPL PLIN1 POLD1 PPARG PRSS1 PSMB8 SMPD1 SPINK1 ZMPSTE24) were evaluated.

Results

Sixty-six patients were evaluated, identifying 39 (59%) with severe primary HT. Familial Chylomicronemia Syndrome (FCS) was identified in 14 (36%) of the 39 cases of severe primary HT. The main findings are shown in table 1. Compared with other etiologies, FCS patients presented an increased, precocious and recurrent incidence of pancreatitis, earlier detection and higher levels of TG. In patients with severe HT without identification of primary causes, a high incidence of alcoholism and diabetes was observed, with a tendency to higher glycated hemoglobin values among these, in addition to median Body Mass Index compatible with obesity.

Conclusion

FCS patients had the most severe clinical presentation of HT. The high prevalence of secondary factors for HT in patients with a negative genotype reinforces the indication of adequate management of these variables even in cases of primary etiology, aiming at not overlapping pathological mechanisms. In cases of severe HT, metabolic control is still a challenge.
A-224 Comparative Analysis of Clinical and Laboratory Parameters of Different Subtypes of Familial Partial Lipodistrophy
Authors: Veras V R , Castelo M C , Costa C L , Vasconcelos L T , Fernandes V O , Lima R S , Vasconcelos M P , Lima G P , Araujo J S , Montenegro A D , Ponte C M , Queiroz L L , Melo I D , Flor A C , Lopes A C , Montenegro R M
Published: September 2023

Background

Lipodystrophy is a disease characterized by changes in body fat deposits. They are classified according to the extent of fat loss (generalized or partial) and the form of inheritance (inherited or acquired). Family partial lipodystrophy (FPL) are rare forms characterized by distribution of centripetal body adiposity, poorly controlled diabetes mellitus (DM) and severe dyslipidemia.

Methods

Fourty-two FPL patients were evaluated, whose were followed in the lipodistrophy outpatient clinic of the Federal University of Ceará/Brazil. Twenty-two had previous positive molecular test for FPL, among which 19 had an LMNA mutation and 3 had a PPARG mutation. Twenty patients had a negative genetic test but met clinical criteria for lipodystrophy, which were thigh skinfold <20 mm for females and <10 mm for males or fat mass ratio (FMR) between trunk and lower limbs >1.2. Eight patients in the negative genotype group met criteria for Köbberling Syndrome (Köb index >3.477). The others 12 patients were classified as FPL indeterminate subtype (FPLX).

Results

PFL+ patients perceived the lipodystrophic phenotype before the other groups. All groups had high A1c medians, with the Köbberling group having the highest median (9.1%). However, patients with FPL+ had a higher median insulin dose. Diabetic polyneuropathy was the most prevalent complication in the three groups. Median peak triglycerides were similar for the three groups, with the Köbberling group having the greatest variability. There no pancreatitis episodes in the FPL+ group, but Köbberling e FPLX did. The main findings are shown in Table 1.

Conclusion

FPL is a disease with a broad spectrum of phenotype and genotype. It is usually associated with poor DM control, early DM complications and severe hypertriglyceridemia, as our patients demonstrated. In these cases, metabolic control is still a challenge.
A-228 Performance Evaluation of the LabGenius C-CT/NG-BMX Assay for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae
Authors: Lim Y , Kweon O , Lee M
Published: September 2023

Background

The LabGenius C-CT/NG-BMX assay (LabGenius CT/NG; BIOMEDUX, Gyeonggi-do, Republic of Korea) is a recently developed real-time polymerase chain reaction assay that can simultaneously detect sexual transmitted pathogens (Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG)) in vaginal swab specimen or urine specimen.

Methods

To evaluate the analytical performance, a total of 343 vaginal swab and 167 urine specimens were selected to compare the LabGenius CT/NG with the BD MAX™ CT/GC/TV (Becton, Dickinson and Company, NJ, USA). In addition, using binomial logistic regression analysis, we estimated the limit of detection which 95% (Lod95) detection rate were achieved in the LabGenius CT/NG.

Results

The LabGenius CT/NG showed almost perfect agreement with the BD MAX™ CT/GC/TV (κ = 0.826 for CT, κ = 0.944 for NG), and overall agreements between two assays were 91.6% for CT and 97.8% for NG, respectively. The LoD95 values using vaginal swab and urine specimens were 9.9 and 7.8 copies/uL for CT, and 7.6 and 5.1 copies/uL for NG, respectively.

Conclusion

In this study, LabGenius CT/NG demonstrated acceptable analytical performance compared to BD MAX™ CT/GC/TV, and this assay could be a cost-effective option for routine and follow-up test for detection of sexual transmitted pathogens.
A-229 Immune Biomarkers Associated with COVID-19 Disease Severity in an Urban, Hospitalized Population
Authors: Chambliss A B , Aljehani M , Tran B , Chen X , Elton E , Garri C , Ung N , Matasci N , Gross M E
Published: September 2023

Background

We sought to identify immune biomarkers associated with severe Coronavirus disease 2019 (COVID-19) in patients admitted to a large public county hospital during the early phase of the SARS-CoV-2 pandemic. We hypothesized that we could identify clinically relevant immune markers at the time of initial hospital admission that could be used to predict the course of COVID-19 illness.

Methods

The study population consisted of SARS-CoV-2 positive patients admitted for COVID-19 (n = 58) or controls (n = 14) at the Los Angeles County University of Southern California Medical Center between April-December 2020. Immunologic markers including chemokine/cytokines (IL-6, IL-8, IL-10, IP-10, MCP-1, TNFα) and serologic markers against SARS-CoV-2 antigens (including spike subunits S1 and S2, receptor binding domain (RBD), and nucleocapsid (N)) were assessed in serum collected on the day of admission using custom MILLIPLEX® immunoassay panels. Result values were computed using mean fluorescent intensity in individual samples fit to a standard curve using a 5PL logistic formula with power law variance. Comparison of patient demographic, clinical, cytokines and immunoglobulins characteristics between mild vs moderate/severe COVID-19 groups were conducted using Wilcoxon tests for continuous variables and Chi-square tests for categorical variables. Linear support vector machine models were fitted to perform the binary classification task of predicting mild vs moderate/severe COVID-19 using the python library scikit-learn.

Results

SARS-CoV-2 antibody levels were significantly elevated in patients with the highest COVID-19 disease severity, with IgM S1, IgG N, IgG RBD, IgG S1, and IgG S2 showing statistical significance between mild vs moderate/severe disease group medians (P = 0.037, 0.032, 0.007, 0.003, and 0.015, respectively). Of the chemokines/cytokines tested, only IP-10 showed significance across the disease groups (medians 640.8 pg/mL in mild, 493.3 pg/mL in moderate/severe, and 259.9 pg/mL in control, overall P = 0.005). The linear support vector machine model achieved an accuracy of 64% and an AUROC of 0.81 in predicting COVID-19 severity status. The most important clinical variables for predicting disease severity were white blood cell count, diastolic blood pressure, and platelet count, while the most important serologic markers were IgG anti-SARS-CoV-2 N, S1, S2, TNF-α, IP-10, and IL-10.

Conclusion

Our results suggest that IP-10 and anti-SARS-CoV-2 antibody measurements could be useful to identify patients most likely to experience the most severe forms of the disease. Strengths of this study include a focus on a racially and ethnically diverse patient population and a combined analysis of both cytokine/chemokine and immune response (antibody) biomarkers. However, we emphasize that our subjects were enrolled at a time before widespread vaccination against SARS-CoV-2.
A-233 Novel Microfluidic System for Antimicrobial Susceptibility Testing
Authors: Bajer-Borstyn S , Zurawska G
Published: September 2023

Background

Aiming to enhance antibiotic susceptibility testing (AST), BacterOMIC combines microdilution AST with cutting-edge microfluidics to quantitatively evaluate all clinically relevant antibiotics on a single disposable panel. In this study, we evaluated the performance of BacterOMIC in determining minimum inhibitory concentrations (MICs) of selected agents against Gram-positive and Gram-negative bacteria and in detecting the presence of extended spectrum beta-lactamase (ESBL) produced by Enterobacterales.

Methods

Using the BacterOMIC UNI Panel, we characterized bacterial strains collected from Polish hospitals in 2020–2022. We inoculated the BacterOMIC panels with bacterial suspensions in cation-adjusted Mueller-Hinton broth at a density of 5*10^5 CFU/mL. The panels then incubated in an analyzer for 16 h, and results were automatically calculated via built-in analytical software. For comparison, we obtained reference MIC data from laboratories contracted for determining strain MIC values via microdilution. We calculated the essential agreement (EA%) and bias according to ISO20776.We also qualitatively assessed several antibiotics via our panel. Categorical agreement (CA%) and discrepancies were determined for these antibiotics according to ISO20776.To assess ESBL detection, we compared BacterOMIC results with data obtained in our internal laboratory using the MIC Test Strip ESBL (Liofilchem).

Results

With the BacterOMIC system, CA% values exceeded 90% for amoxicillin, benzylpenicillin, ceftazidime/avibactam, ciprofloxacin, erythromycin, gentamicin, meropenem, moxifloxacin, tedizolid, and vancomycin. EA% values exceeded 90% for the following antimicrobials, with a bias of less than 30%.

By comparing with our reference method, we found that BacterOMIC detected ESBL with a specificity of 92% (confidence interval [CI] 95%; 81%–98%) and sensitivity of 97% (CI 95%; 84%–99%).

Conclusions

Our data demonstrate that BacterOMIC provides reliable MIC and ESBL results for assessing the drug susceptibility of Gram-positive and Gram-negative bacteria against 25 agents in a single panel. Thus, the BacterOMIC system provides a valuable tool for automated AST systems.
A-240 Rapid and Reliable Identification of Microorganisms from Early Growth of Positive Blood Cultures Using MALDI-TOF Mass Spectrometry
Authors: Roemmich B L , Yarbrough M L , Alvarado K K
Published: September 2023

Background

Rapid identification of organisms causing bloodstream infections is critical for treatment. Traditional workflows rely on 18–24 h growth of isolated colonies. Our objective was to evaluate identification of early growth using Bruker and VITEK® MS PRIME MALDI-TOF systems.

Materials

Positive blood cultures (BACT/ALERT® FA/FN Plus; bioMérieux VIRTUO®) were included if bottles were positive <8 h and had time-to-positivity of <40 h. Broths were sub-cultured to blood agar and incubated at 35°C/5% CO2. MALDI-TOF identification of 6–8 h growth (short incubation, SI) and 18–24 h growth (standard incubation, SDI) was performed by a high (HEU, >1 year) and low (LEU, <1 month) experience user. Each identification was performed using standard set-up for Bruker and VITEK MS PRIME, and target set-up using VITEK PICKMETM pen. Identification level and time-to-result (TTR) were measured and compared using Fisher’s exact and t-test.

Results

53 organisms (36 Gram-positive, 15 Gram-negative, 2 yeast) were isolated from 50 blood cultures. The HEU achieved species-level identification for 87% on VITEK MS PRIME using routine set-up and PICKME after SI vs 74% on Bruker, while 66% and 70% of organisms were identified on VITEK MS PRIME vs 75% on Bruker by the LEU (Table). After SDI, ≥94%(HEU) and ≥87%(LEU) of organisms were identified, with no differences noted by set-up or user experience (P > 0.05). Species-level identification after SI was higher for Gram-negative (100%) vs Gram-positive (67–86%) organisms for the HEU. PICKME pen usage increased identifications to 100% from 67% for Gram-negatives for the LEU. For mixed cultures (n = 3), only 1 of 2 organisms was identified after SI. TTR was significantly longer(P < 0.05) for SI vs SDI and Bruker vs VITEK MS PRIME for the HEU.

Conclusions

Identification of microorganisms after short incubation on solid media achieves early, reliable identification for a majority of positive blood cultures without need for additional hands-on time or extraction.
A-245 Reagent Lot Variation—When should I be Concerned?
Authors: Vincini G , Dimech W
Published: September 2023

Background

Reagent lot variation is often considered a major source of concern for infectious disease serology testing. Regular review of quality control testing data for specific assays confirms that, when using traditional statistical methods, such as using small datasets to establish mean/SD and then applying Westgard rules, reagent lot variation is the most common cause of variation observed. To investigate every incident is time consuming, costly and likely unnecessary in the majority of cases. But how do we create an alternative to monitoring QC data that accepts normal reagent lot variation yet highlight unacceptable variation? Applying the results from two assays using the same multimarker QC sample to traditional and an alternative QC monitoring method such as QConnect highlights when we should be concerned with lot variation and when the variation is normal.

Methods

QC testing data from 14 lots of the multimarker QC “Optitrol Blue” over a three year period tested on two assays—Abbott ARCHITECT Anti-HCV (n = 54 102) and Abbott ARCHITECT HIV AgAb Combo (n = 62 682) were reviewed for lot variation using traditional and alternative QC monitoring methods.

Results

Numerous examples of lot variation were identified from the two assays over the three-year period. Applying traditional QC methods resulted in frequent recalculation of mean/SD to accommodate the lot variation, effectively making the lot variation part of the routine, negating its importance, and making the clinical significance of reagent lot variation difficult to ascertain. Using an alternative QC monitoring method such as QConnect, which incorporated normal lot in calculations to create a constant acceptance range, removed the uncertainty and highlighted instances where variation was outside ‘normal’, triggering further investigation by using meaningful QC ranges. A clear example was observed where two similar looking Levey-Jennings charts (one for ARCHITECT HCV and one for ARCHITECT HIV) demonstrated reagent lot variation that was detected as an outlier whereas Traditional methods identified all reagent lots as being outliers.

Conclusion

In infectious disease serology testing, reagent lot variation is frequent, normal, and rarely a cause for concern. However, it is difficult to determine how much variation is acceptable when using traditional QC methods, because most lot changes are flagged as “rejections”. QC processes that incorporate normal reagent lot variation, derived from historical data, allows for rapid identification of unacceptable variation, saving money and time (particularly when all reagent lot variation identified as outliers need unnecessary investigation), while reducing risk of poor results.
A-248 Evaluation of NextGene™ MTB/NTM Detection Kit for Detection of Mycobacterium tuberculosis Complex and Nontuberculous Mycobacteria in Sputum and Culture Specimens
Authors: Ahn J , Kim D , Lee W
Published: September 2023

Background

Tuberculosis, an infectious disease, is a major cause of deteriorating health, and, until SARS-CoV-2 (COVID-19) became a pandemic disease, a major cause of death worldwide. The recently developed NextGene™ MTB/NTM Detection Kit is designed for detection of Mycobacterium tuberculosis complex (MTB) using IS6110 genes and MPB64 genes, and for detection of nontuberculous mycobacteria (NTM) using 16S rRNA genes for resolution of false positive and false negative results, and for development of more sensitive and specific real-time PCR products. The purpose of this study is to examine the clinical sensitivity and specificity of the NextGene™ MTB/NTM Detection Kit in order to verify its clinical efficacy.

Methods

A total of 446 residual clinical specimens were obtained from 274 sputum and 172 culture samples collected from July to August 2021. Diagnostic tests were performed in order to confirm that these residual samples were positive and negative; 344 specimens were positive for MTB or NTM, and 102 specimens were confirmed as negative for both MTB and NTM. Measurement of positive/negative percent agreement values and kappa coefficients was performed for comparison of diagnostic performance between the NextGene™ and Advansure assays. Positive and negative controls were included in each run.

Results

Of the 446 samples (274 sputum and 172 culture samples), 344 specimens showed a positive result and 102 specimens showed a negative result. Results of the comparison tests were all consistent for detection of MTB and NTM. Both MTB and NTM met the criterion for evaluation of target validity of kappa value 0.8 or higher in sputum and culture samples. Results of the evaluation of clinical sensitivity and specificity were consistent with both clinical diagnoses.

Conclusion

This study was conducted in order to examine the clinical sensitivity and specificity of the NextGene™ MTB/NTM Detection Kit in order to verify its clinical validity. Residual samples from sputum and culture specimens from patients who were suspected being infected that were confirmed positive or negative for MTB and NTM were used in this study with the goal of establishing the already commercially available licensed product as a control reagent for comparative analysis of the clinical performance of the NextGene™ MTB/NTM Detection Kit. Compared to existing kits that are widely used, consistent results from comparison of the NextGene™ MTB/NTM Detection Kit have been reported with comparable clinical sensitivity and specificity, thus it is regarded as showing the same performance.
A-256 Clinical Performance of Presepsin for Sepsis in the Emergency Department Patients in a Tertiary Hospital in Korea
Authors: Ji E , Lee S
Published: September 2023

Background

Sepsis is a life-threatening condition that requires prompt recognition and treatment. Presepsin is a new diagnostic biomarker of sepsis that has been implemented as a selective reimbursement in Korea and was introduced in our hospital in October 2022. This study aimed to evaluate the clinical performance of the Presepsin Assay (Sysmex, Kobe, Japan) on the Sysmex HISCL-5000 system in the southeast population in Korea.

Methods

The study is a retrospective study that included emergency department (ED) and ED-based intensive care unit (EICU) patients tested for presepsin from August 18, 2022, to February 11, 2023. We calculated the patients’ sepsis-related organ failure assessment (SOFA) score at the time of blood collection for presepsin from the electronic medical record. Presepsin, procalcitonin, and high-sensitivity C-reactive protein (hsCRP) were also investigated. The sepsis markers for sepsis prediction were evaluated using receiver operating characteristic (ROC) curve analysis and area under the curve (AUC).

Results

A total of 81 patients, including 66 ED and 15 EICU patients, were tested for presepsin. The presepsin results ranged from 101 to 8788 pg/mL (Mean 1,005.9 pg/mL, Standard deviation 1,509.4). In ROC curve analysis, three biomarkers—presepsin, procalcitonin, and hsCRP generated an area under the curve (AUC) value of 0.698, 0.670, and 0.694 for predicting sepsis, respectively, for the threshold ≥7 of SOFA score to screen the risk of sepsis.

Conclusion

The clinical performance of presepsin in the ED-based setting in Korea was found to be comparable in detecting the risk of sepsis. Further research is needed to determine the optimal use of presepsin in the other clinical areas of the hospital, such as intensive care units, and to assess its impact on patient outcomes.
A-264 Comparison of the ZEUS Scientific Lyme Assays to the DiaSorin Liaison Lyme Assays Using a Modified Two-Tiered Testing Algorithm for Lyme Disease
Authors: Walsh M E , Sietsma D J , Martin I W , Brunelle L A
Published: September 2023

Background

Lyme borreliosis is the most common vector-borne disease in the United States. Modified two-tiered testing (MTTT) strategies have recently been developed that use enzyme immunoassays as the second tier test in place of an immunoblot. We directly compared two sets of MTTT assays with samples obtained from the northeastern United States, a Lyme disease endemic area.

Methods

Remnant specimens from 120 patients initially tested by the ZEUS Scientific Lyme ELISAs in accordance with an MTTT algorithm were analyzed with the DiaSorin Lyme chemiluminescent immunoassays. The ZEUS assays were performed on a DYNEX DS2 and the DiaSorin assays were performed on the DiaSorin Liaison XL. Analytical concordance was evaluated.

Results

Of the 25 samples that were negative by the ZEUS VlsE1/pepC10 IgG/IgM assay, 100% (25/25) were negative by the DiaSorin Lyme Total Antibody Plus assay. Of the 95 samples that were presumptive positive or equivocal by the ZEUS IgG/IgM assay, 64% (61/95) were presumptive positive or equivocal and 36% (34/95) were negative by the DiaSorin Lyme Total assay. Samples that tested presumptive positive or equivocal on the ZEUS IgG/IgM or DiaSorin Lyme Total were evaluated by the respective IgG and IgM assays. Positive IgG results and negative IgM results demonstrated >90% agreement between the ZEUS and DiaSorin assays (Table 1). Overall clinical interpretation was concordant between the ZEUS and DiaSorin MTTTs in 57% (54/95) of patients who tested presumptive positive or equivocal on the ZEUS IgG/IgM. Twenty-four samples that tested positive for IgM by the ZEUS assay tested negative for DiaSorin Lyme Total or IgM assays.

Conclusion

Comparison of the DiaSorin Lyme assays to the ZEUS Lyme assays using an MTTT algorithm suggests that the DiaSorin assays would result in fewer positive screening tests, decreasing unnecessary secondary testing, and may result in fewer patients treated with antibiotics.
A-265 Disparities Among SARS-CoV-2 Antibody Positivity in Healthcare Workers
Authors: Mullins K E , Christenson R
Published: September 2023

Background

Early in the COVID-19 pandemic disparities in hospitalizations and mortality rates were seen between race/ethnicities. Currently, the CDC reports that there is a 2.1× and 1.6× increase in risk of hospitalizations and deaths, respectively, for Black non-Hispanic (NH) persons when compared to White NH persons. Additionally, studies have found that Black and Hispanic individuals are more likely to test positive for SARS-CoV-2 as compared to other ethnicities/races. Many socioeconomic factors have been associated with increased risk, however, few if any, studies have investigated the disparities in SARS-CoV-2 exposure for healthcare workers.

Methods

To gain a better understanding of the risk of SARS-CoV-2 exposure in healthcare workers, EDTA plasma samples were collected from healthcare workers associated with the University of Maryland Medical System between June 1st, 2020, and August 31st, 2020. Plasma samples were tested for Anti-SARS-CoV-2 Spike Ig/M/A Antibodies using an in-house developed Enzyme-linked Immunoassay and the Ortho Vitros COVID-19 Total Antibody assay.

Results

7850 healthcare workers were enrolled (82.3% female). 26.7% were Black NH and 75.3% were White NH individuals. No differences were seen between age or sex between the two groups. Overall, the positivity rate for Anti-SARS-CoV-2 antibodies was 3.5%, however, when stratified by race/ethnicity 6.7% of Black NH individuals and 2.4% of White NH individuals were positive for Anti-SARS-CoV-2 antibodies. When stratified by sex there were no statistically significant differences.

Conclusion

These findings suggest that Black NH healthcare workers were 2.6 times more likely to have been exposed to SARS-CoV-2 when compared to White NH individuals, irrespective of sex. Further understanding of the geographic and socioeconomic factors that play a role in these findings is needed. However, these findings suggest that heath disparities are prevalent and need to be addressed not only in the communities that our healthcare workers treat, but within our healthcare worker communities themselves.
A-275 Clinical Evaluation of SMARTCHEK® SARS-CoV-2 Detection Kit and SMARTCHEK® SARS-CoV-2 Fast Detection Kit for Detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Nasopharyngeal Swabs
Authors: Ahn J , Lee W , Yoon S , Cho S
Published: September 2023

Background

Rapid and accurate diagnosis of COVID-19 is very important in our daily lives. SMARTCHEK® SARS-CoV-2 Detection Kit (Genesystem, Daejeon, Korea) and SMARTCHEK® SARS-CoV-2 Fast Detection Kit (Genesystem) are rapid PCR kits for SARS-CoV-2 using a microfluidic chip-based PCR method. These two kits can provide results in 40 min and 20 min, respectively, enabling rapid point-of-care diagnostics. In this study, the diagnostic performance of SMARTCHEK® SARS-CoV-2 Detection Kit and SMARTCHEK® SARS-CoV-2 Fast Detection Kit using UF-340 Four-in-One Real-time PCR System (Genesystem) were compared to STANDARD M nCoV Real-Time Detection kit (SD Biosensor, Korea) using CFX96 Dx System (Bio-Rad, USA) in nasopharyngeal swabs.

Methods

Nasopharyngeal swabs were collected and frozen (at ≤−70°C) using 500ul of the residual samples of 64 patients who underwent COVID-19 PCR at Ajou University Hospital. After thawing, RNA was extracted with TANBead OptiPure Nucleic Acid Auto Plate (Taiwan Advanced Nanotech Inc., Taoyuan, Taiwan) using SLA-E13200 (Taiwan Advanced Nanotech Inc.), and real time PCR was performed according to the manufacturer’s instructions. For correlation evaluation, positive, negative, and overall concordance rates were calculated.

Results

Among 64 samples, results from STANDARD M nCoV Real-Time Detection kit showed 49 negative (77%) and 15 positive (23%) results. Ct value exceeding 30 was observed in 4 samples (27% of positive samples). The positive, negative, and overall concordance rates of the STANDARD M nCoV Real-Time Detection Kit and SMARTCHEK® SARS-CoV-2 Detection Kit were all 100%. One positive sample with the STANDARD M nCoV Real-Time Detection Kit (Ct value: E gene 34.5, RdRp gene 35.5) was excluded from the analysis because the results could not be determined even after repeated testing with SMARTCHEK® SARS-CoV-2 Detection Kit. The positive, negative, and overall concordance rate of the STANDARD M nCoV Real-Time Detection Kit and SMARTCHEK® SARS-CoV-2 Fast Detection Kit were 87%, 100%, and 97%, respectively. Both of the two discrepant samples had a Ct value close to 35.

Conclusion

SMARTCHEK® SARS-CoV-2 Detection Kit and SMARTCHEK® SARS-CoV-2 Fast Detection Kit can quickly and accurately diagnose COVID-19 in nasopharyngeal swabs and is especially useful in small to medium-sized laboratories or areas where space or equipment is limited.
A-285 Performance Evaluation of LIAISON® QuantiFERON®-TB Gold Plus Assay and Its Use in Long-Term Care Facilities
Authors: Khoury R , Gandhi A , Gudaitis D , Gudaitis P
Published: September 2023

Background

Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis with 7860 cases reported in 2021 in the United State and estimated 13 million people are living with Latent TB infection (LTBI); Early detection of TB infection is crucial to prevent the spread of the disease; there are two types of tests for TB and LTBI: Tuberculin Skin Test (TST) and Interferon-Gamma Release Assay (IGRA). Although TST has good sensitivity but false-negative reactions occur in certain population and the specificity of is decreased among persons with prior Bacillus Calmette-Guérin (BCG) vaccination, especially those vaccinated post-infancy and those with repeat vaccination. Similarly, persons living in areas where nontuberculous mycobacteria are common are at increased risk of having false-positive TST reactions. IGRA is blood-based laboratory test that measures responses to TB-specific peptide antigens in whole blood. Like the tuberculin skin test (TST), it is an indirect test for M. tuberculosis infection, but is more specific than TST and is unaffected by prior BCG vaccination and most environmental mycobacterial infections.

Methods

The LIAISON® QuantiFERON®-TB Gold Plus assay is an in vitro diagnostic test for the detection of interferon-γ (IFN-γ) in human lithium heparin plasma by chemiluminescence immunoassay (CLIA) using the LIAISON ® XL Analyzer. The clinical specificity and sensitivity were 96.9% and 84.4% respectively. Clinical studies have shown Positive Percent Agreement (PPA) of 97.4% and Negative Percent Agreement (NPA) of 98.6%. We evaluated the precision, reproducibility, and correlated patient results to our reference lab results. 452 samples collected from Long-Term Care facilities resident were run over 9 months. Statistical analyses were done using Analyse-it.

Results

The percentage agreement for precision, reproducibility, and accuracy were 100%. The correlation with the reference laboratory was 100% agreement. We found 14.8% of samples tested were positive, 83.2% were negative and 2.0% were indeterminate.

Conclusion

The LIAISON® QuantiFERON®-TB Gold Plus assay offers the benefit of a fully automated with high sensitivity and specificity. The faster turnaround will aid the physician in the diagnosing M. tuberculosis, eliminates the need for two-step testing, and is preferred in patients who received BCG vaccination. In addition, with the growing geriatric population, the availability of this test will give the physician the opportunity to follow the 2016 American Thoracic Society (ATS)/Infectious Disease Society of America (IDSA)/CDC clinical practice guidelines for using IGRAs in older patients.
A-286 Performance Evaluation of Molecular Clostridium Difficile Assay using BD MaxTM System
Authors: Khoury R , Patel P , Gandhi A , Gudaitis D , Gudaitis P
Published: September 2023

Background

Clostridium difficile (C.Diff) is a gram positive anaerobe producing Enterotoxin and Cytotoxin (toxin A and B respectively); toxin B has been reported to be essential for its virulence. It is estimated that C. Diff will cause over half a million infection yearly and one in 11 people over the age of 65 diagnosed with healthcare-associated C.Diff infection die within one month. It is the most common cause of acute diarrhea; residents in Long-Term Care Facilities (LTCF) are more prone to have C. Diff infection (CDI) because of their age, the frequent use of antibiotics, fragilities, co-morbidity, and living environment. Diagnosing CDI is based on clinical signs and symptoms as well as laboratory tests. Several tests available for diagnosing the infection which include: enzyme immunoassays, tissue culture cytotoxicity, anaerobic culture, glutamate dehydrogenase antigen and nucleic acid amplification. The BD MAX™ System is a PCR based assay that provides the sensitivity, specificity and faster turnaround.

Methods

The MAX™ System is an automated in vitro diagnostic test for the direct qualitative detection of the C. difficile toxin B gene (tcdB) in human liquid or soft stool specimens from patients suspected of having Clostridium difficile Infection (CDI).The test is performed directly on the specimen, utilizing real-time polymerase chain reaction (PCR) for the amplification of C. difficile toxin B gene (tcdB). The test utilizes fluorogenic sequence-specific hybridization probes for detection of the amplified DNA. The test was validated for accuracy, precision, and patient correlation to enzyme-immunoassay using Premier Toxins A & B is an enzyme immunoassay for the direct detection of Clostridium difficile toxin A and toxin B in stool samples. Statistical analyses were done using Analyse-it.

Results

The percentage agreement for precision, reproducibility, and accuracy were 100%. We had 100% agreement for positive patients on EIA and 85% for negative patients on EIA; however, upon investigation we found the discrepancies were due to false negative EIA results.

Conclusion

The BD Max gave the benefit of a fully automated with high sensitivity and specificity for the presence of toxin B producing C. Diff. The faster turnaround gives the physician the ability to diagnose CDI and prevent spreading of the disease to other patients. It is very important to remember that C.diff infection can be prevented with appropriate use of antibiotics and implementing antibiotic stewardship and infection control plan to prevent and stop spreading of the infection.
A-305 Evaluation of the Analytical Performance of Rapid Tests to Detect Arboviruses Antibodies Intended for Point-of-Care Screening
Authors: Domingues R S , Martins L A , Zauli D A , de Lima A B , Silva J D
Published: September 2023

Background

Arboviruses are recognized as a group of RNA viruses that can transmit diseases by different sucking arthropods vectors, especially Aedes Aegypti, a mosquito that can transmit several viral diseases including Dengue (DENV) and Chikungunya (CHIKV). The re-emergence and spread of these diseases are considered a concern in global health and Latin American countries, such as Brazil. Therefore, it's necessary to offer efficient, simpler, and faster diagnosis tools for accurate case identification and help promote adequate treatment. Rapid tests (RTs) can be used as one of these tools for qualitative detection and it's important mainly in point-of-care (POC) testing places. Thus, this work aimed to evaluate RTs to identify antibodies (IgG and IgM) of DENV and CHIKV.

Methods

Serum samples were previously selected as positive, negative, or inconclusive results based on ELISA method or RTs confirmation. It was used the immunofluorescence-based ECO Diagnostica RTs kits (ECO-F Dengue IgG/IgM and ECO-F ChikV IgG/IgM). The samples were diluted in proper buffer and incubated for 15 minutes. The results were read in ECO Reader F200 equipment that uses the Cut-Off value for results. Cut-Off values >1.00 are considered positives, while Cut-off values <1.00 are considered negatives.

Results

The results are presented in Tabela 1.

Conclusion

Both RTs showed specificity that surpasses 88%. The sensibility obtained was 57,14% and 33,3% for DENV and CHIKV tests respectively. All samples that obtained inconclusive results by other methodologies showed negative results in the RTs assessed. The NPV was 64% and 86,96% for DENV and CHIKV tests respectively. Although RTs can be used to help in the initial screening of diseases caused by arboviruses, it is necessary to carry out molecular tests for confirmation, especially in negative cases.
A-329 Preliminary Clinical Method Comparison of a Near-Patient Platform for Low Blood Volume Testing of aFXa in Pediatric Patients on Heparin Therapy
Authors: Aljudi A , Lam W , Sista R , Pamula V , Rogers B
Published: September 2023

Background

Up to 15% of hospitalized children receive heparin therapy and require frequent monitoring for Anti-Factor Xa activity (aFXa) and activated partial thromboplastin time (aPTT) to achieve hemostatic balance. Current heparin tests require large blood volumes, which can lead to iatrogenic anemia with frequent sample collection. We performed a small clinical method comparison of a rapid, near-patient platform for simultaneous whole blood testing of aFXa from 50 μL of sample against the clinical standard test. The aPTT assay is in development on the same digital microfluidic (DMF) platform.

Methods

Four DMF instruments were placed in our laboratory. Preliminary precision of the DMF aFXa assay was obtained using commercial controls (n = 19 for aFXa at 0.98 U/mL; n = 20 for aFXa at 0.42 U/mL). We obtained whole blood or plasma from residual aFXa samples from pediatric patients. Venous samples were collected from patients for routine testing in the core laboratory, and 150 μL of whole blood was saved for aFXa method comparison testing. Patients were either on low molecular weight heparin or unfractionated heparin. We performed a method comparison study to determine assay equivalence to in-house clinical standard tests using plasma for aFXa on the Stago STA R MAX to both plasma and whole blood on the DMF platform.

Results

For precision, we observed an assay coefficient of variation (CV) of 4.68% and 6.6% for aFXa at 0.98 U/mL and 0.42 U/mL, respectively. The aFXa assay correlated well (R2 = 0.94 for whole blood (n = 9) and R2 = 0.97 for plasma (n = 10)); additional studies are needed to demonstrate aPTT assay equivalence.

Conclusions

We demonstrated good correlation of the DMF aFXa assay to the clinical standard test. The low blood volume requirement make these tests suitable for use in heparin monitoring where frequent testing is necessary. A large scale clinical method comparison is planned to ensure clinical utility.
A-332 Sweat rate does not influence sweat chloride concentration
Authors: Omosule C , Roper S
Published: September 2023

Introduction

The recommendations for sweat chloride ([Cl-]) testing from the Clinical and Laboratory Standards Institute (CLSI C34-A4 2019) endorse a minimum sweat rate of 1g/m2/min to validate efficient sweat stimulation. For labs that use macroduct ® collection devices, this rate corresponds to a sweat volume ≥15 µL collected within a 30-minute period. Bilateral collection and testing is also advised to improve the odds of obtaining a sufficient specimen from at least 1 site. When both sites fail to meet the minimum rate, the test is invalid (QNS) and should be repeated, potentially delaying Cystic Fibrosis (CF) diagnosis. In this study, we evaluate the premise for the minimum sweat rate by investigating the relationship between sweat rate and [Cl-]. In a sub-analysis, residual sweat available after clinical testing is used to examine the effect of specimen pooling on [Cl-]. This study has the potential to inform best practices for future sweat testing guidelines, decrease QNS rates, and reduce time to CF diagnosis.

Methods

Thirteen months of data from sweat tests performed at St. Louis Children's Hospital were reviewed. All collections were performed using macroduct devices following CLSI 34-A4 guidelines (results from QNS specimens were not reported clinically). Pearson correlation was calculated to examine the relationship between sweat rate and [Cl-] (n = 354). Deming regression was applied to evaluate the effect of specimen pooling, versus results from individual sites, in 19 collections with residual volume after clinical testing.

Results

Figure 1

Conclusion

Negligible correlation between rate and [Cl-] across a wide range of values suggests the current minimum volume for macroduct collections (15 µL) may be overly stringent. Reporting of [Cl-] in specimens with ≥10 µL sweat may decrease QNS rates without compromising accuracy. Preliminary data suggests pooling of bilateral collections may be a feasible option to achieve the minimum volume required for testing (10 µL).
A-349 Septec: A Microfluidic Platform for the Rapid Diagnosis of Bloodstream Infection Diagnosis and Associated Sepsis Management
Authors: McArdle H , Cassedy A , Adamson K , Burke D , Farghaly Mohammed A , McEvoy N , Smyth M , Curley G
Published: September 2023

Background

Sepsis is a life-threatening disorder resulting from a dysregulated host response to infection. Globally, sepsis is responsible for 11 million deaths annually and is associated with high mortality and morbidity. Sepsis can arise from any infection by microbes or viruses; however, the most common cause is bloodstream infection (BSI) via bacterial pathogens. Rapid identification of organisms responsible for BSI may reduce time until the administration of suitable antibiotics and employment of rapid diagnostics at patient bedside further strengthens their value as informed clinical decisions can be made and acted upon within shorter timeframes, potentially enhancing patient outcomes and preventing progression to more critical sepsis or septic shock. This study reports on the analytical and clinical performance of the SepTec microfluidic assay, an in-vitro diagnostic device capable of rapid detection of bloodborne pathogens of gram-positive, gram-negative and fungal origin from whole blood within 15 minutes.

Methods

Analytical performance of the SepTec assay was studied as follows: limit of detection (LoD), reproducibility and impact of interfering substances. Sterile and infected blood samples were obtained either through the generation of contrived samples or through clinical collaboration. Clinical performance was determined retrospectively and prospectively on a total of 146 patients. For both the retrospective and prospective clinical studies, results were compared against blood culture.

Results

The LoD of the SepTec assay for S. Aureus, E. coli and C. albicans from contrived blood samples was 10 CFU/mL for each pathogen. CVs were calculated at 4% for organism detection in whole blood samples. From retrospective and prospective analysis, the SepTec assay showed 100% sensitivity and >96% specificity.

Conclusion

The SepTec assay can detect microbes from blood and differentiate between gram-positive, gram-negative or fungal pathogens with high sensitivity and specificity. Turnaround time for the test is estimated at 15minutes, rendering it with the potential to be a significantly more rapid approach than the gold-standard blood culture, or many molecular approaches. It is hoped that this work with yield a point-of-care diagnostic platform which will enhance sepsis management, overall improving patient outcomes.
A-371 Comparative Evaluation of POCT Based Lysophosphatidylcholine Measurement
Authors: Rim J , Choi H , Jang H , Jang J , Kang H , Lim J
Published: September 2023

Background

Lysophosphatidylcholine (LPC), also referred to as lysolecithin, is a phospholipid intermediate whose concentrations have been correlated with such diseases as cancer, artherosclerosis and diabetes. Recently, serum LPC concentrations have been reported to be candidate biomarker for bacterial infection and sepsis. In this study, we evaluated the comparative performance of the point-of-care test (POCT) measurement of LPC using CareBuddy Multi Analyzer.

Methods

A total of 120 serum samples were analyzed for LPC by enzymatic spectrophotometry (CareBuddy Multi analyzer, CareBuddy catridge) and mass spectrometry based method (TSQ Altis LC/MS/MS) as the reference method. Additionally, subset of samples with enough remnant volumes were assessed for PCT and CRP using electrochemiluminescence immunoassay (Roche Cobas e801, Roche Elecsys BRAHMS PCT) and immunoturbidimetric assay (Roche Cobas c702, Sekisui Nanopia CRP), respectively. The equivalence and correlation among the methods were evaluated using linear regression analysis.

Results

The LPC measurement by POCT analyzer showed high correlations with the LC-MS based reference method (y = 1.02x + 1.26). The LPC measurement by POCT showed correlation coefficient for PCT (Pearson's r = −0.316) and CRP (Pearson's r = −0.618). Upon applying clinical cutoffs for qualitative result, LPC POCT measurement showed good agreements to each reference methods.

Conclusion

In summary, our results suggest that the quantitative measurement for LPC via POCT device in human serum samples possess possible clinical feasibility as a novel sepsis biomarker.
A-373 Comparison of the CoaguChek ® and Coag-Sense ® PT2 Meter Point of Care INR Devices
Authors: Schumann T , Karon B , O'Connor C , Jennifer L , Blanco J , Hartman L , Kramer A , Uy J , Myhre N , Gayle D , Hartung K , David H , Santrach P , McBane R
Published: September 2023

Background

Warfarin monitoring may be done at the point-of-care (POC) at home, in a clinic environment, or be performed using plasma specimens in a central laboratory. With a goal of standardizing International Normalization Ratio (INR) measurements and improving data integrity by enabling electronic transmission of results from any location, we evaluated two POC INR devices against an internal plasma INR reference method.

Methods

We conducted a multicenter study to test the accuracy of two commercially available point of care devices: Coag-Sense PT2 Meter (Coagusense, Inc., Fremont, CA) and CoaguChek XS Pro or XS Plus (Roche Diagnostics, Indianapolis, IN) compared with plasma INR values among warfarin treated patients. Bias and linear regression analysis were assessed for device-plasma INR comparisons. Warfarin dosing decisions were assessed for each device compared to an internal plasma INR reference method (Instrumentation Laboratories ACLTOP 500, 550, 750 analyzers (Werfen Diagnostics, Bedford MA) in one of three CLIA-certified laboratories. The thromboplastin used at our institution for INR measures is HemosIL RecombiPlasTin 2G (R2G) reagent (Werfen Diagnostics, Bedford MA) which has an International Sensitivity Index (ISI) of 1.0.

Results

Two hundred ninety-nine warfarin patients treated across three Mayo Clinic sites agreed to participate in the study. Common anticoagulant indications were atrial fibrillation (63.9%), venous thromboembolism (21.7%) and heart valve prosthesis (15.4%) with a 2.0–3.0 INR target range for 93.6% of patients. For the CoaguChek devices, 81.3% of values fell within 0.2 INR units of plasma INR referent and 95.3% within 0.4 units. The correlation between CoaguChek whole blood and plasma INR was excellent (R2 = 0.93). For the Coag-Sense device, 34.1% of values fell within 0.2 INR units and 60.2% within 0.4 INR units of plasma INR values, with a slightly weaker correlation between Coag-Sense whole blood and plasma INR (R2 = 0.83; P < 0.0001). Mean (± standard deviation) deviation from plasma INR was 0.04 ± 0.2 for CoaguChek compared to 0.4 ± 0.3 for Coag-Sense (P < 0.0001). The difference between POC devices was largely attributed to systematic negative bias between Coag-Sense and ACL TOP plasma INR values. Using the plasma INR as the reference method for dosing decision making, appropriate dosing recommendations would have occurred for 97.7% of CoaguChek and 81.6% of Coag-Sense results.

Conclusion

Compared to our institution's plasma reference method, INR values obtained from the CoaguChek devices (XS Pro and XS Plus) exhibited less systematic bias compared to the Coag-Sense values. This translates to greater percentage of concordant management decisions between POC and laboratory plasma INR methods when the CoaguChek device is used.