bluuebunny/crossref_metadata_2025 huggingface dataset:
A-157 Evaluation of Cellular Stability in Bone Marrow for Flow Cytometry Analysis
Authors: Correa Wengerkievicz Lopes A , Sousa I , Muniz Ribeiro Franzon C , Oliveira Martin Wagner A
Published: September 2023

Background

Plasma cells are sensitive and can rapidly deteriorate after sample collection or due to roughhandling. Delayed sample processing remains a common challenge due to logistical limitations.Specialized tests performed in central pathology laboratories are frequently located aconsiderable distance from healthcare providers. According to the Clinical Flow CytometricAnalysis of Neoplastic Hematolymphoid Cells; Approved Guideline-Second Edition, BM samplescollected in EDTA anticoagulant should be analyzed within 12 to 24 h. The objective of thisstudy was to define the stability of a bone marrow (BM) sample within 48 h through theevaluation of the main cell populations with a focus on plasma cells.

Methods

Nineteen bone marrow samples (without the use of preservative medium) were evaluated at 0, 24 h and 48 h, collected in EDTA anticoagulant and stored at 4°C before processing. To definethe stability of the samples, the MFI (mean fluorescence intensity) was evaluated. The samplepreparation protocol was performed based on the monoclonal gammopathy screening panel attime 0 (CD38 FITC, CD138V500; CD45V450; CD19PECY7, CD56PE, CD27PERCP and KAPPA APCand LAMBDAAPCH7), and at times 24 h and 48 h it was performed a panel with anchor markers (CD45V450, CD19PEcy7, CD38FITC, CD138V500, CD56PE), acquisition in FACS CANTO II and FACSLyric equipment and data analysis performed with Infinicyt software. To assess the impact ofsample storage and the MFIs of individual markers, positive reference populations wereanalyzed using the antigen CD38 for plasma cells, CD19 for B lymphocytes, CD56 for NK cells andCD45 for other populations. Statistical analysis was performed using the Paired t-test,considering statistically significant results those with P < 0.05.

Results

In the present study, the evaluation at 24 and 48 h showed that the populations ofgranulocytes, B lymphocytes and plasma cells did not present a significant difference betweenthe evaluated times. The monocyte population showed a decrease of P < 0.05 in the time 48 h an in the first 24 h it remains stable. In NK cells, despite P < 0.05 between 0–24 h and 0–48 h, it can be observed that between 24 h–48 h the population remained stable.

Conclusion

Evaluating these results, based on the cell type of interest, different delays are acceptable.Despite the greater sensitivity of plasma cells, it was concluded that the evaluation of CD38 asan anchor marker for plasma cells can be used in up to 48 h without significant change inthe MFI evaluation for analysis of this cell with this marker. The differences found in NK lymphoidcell may be due to methodological problems, considering that the analyzed panel is not ideal forevaluating this population. Therefore, it is necessary to carry out more detailed studies for othertypes of cell populations.
A-164 Key Performance Indicators (KPIs) Can be Polluted by Add-on Tests
Authors: Ellison T , Fraser D , Cane P , James D
Published: September 2023

Background

Key Performance Indicators (KPIs) are a measurement of service performance which are measured frequently and can demonstrate the clinical effectiveness of services. We undertook a review of a subset of KPIs following feedback from clinicians in the emergency department that was at odds to our reported KPIs. Our reported KPIs suggested that we were not meeting the turnaround times (TATs) required (1 h from receipt in the laboratory to result availability), however the view of the clinicians was that we were achieving the KPIs needed to manage their patients. We undertook an exercise to quantify the impact of add-on tests to our published KPIs as our laboratory information systems are not able to discriminate tests that are added on at a later time from those that go though as a first pass.

Methods

We reviewed all data (February 2022) for 4 common tests requested in the Emergency Department at King’s College NHS Foundation Hospital: amylase, CRP, paracetamol and high sensitivity troponin. Through a laborious process, we reviewed all records where a test had been added on to compare the turnaround time (TAT) for tests that pass through the first time and those that are added on so that we could quantify the impact of add-ons.

Results

In the month of February 2022, we processed 754 amylase, 4014 CRP, 121 paracetamol and 1414 high sensitivity troponin tests. The highest proportion of add-on tests was experienced with troponin (9.7%), amylase (9.4%) and paracetamol (8.3%). The lowest percentage of add-on tests was CRP (1.9%). Figures to be presented will demonstrate the impact of add-on tests as compared to those that go through as a first pass yield in whisker box plot format, non-truncated.

Conclusion

Add-on tests were polluting the KPIs that we were reporting. The service was delivering a TAT that the clinicians required, however our legacy internal reporting systems were not able to discern the date/time of add-on from that of the receipt of the tube into CSR or strip out the add-ons from the KPI reports and hence the negative impact that they have on reporting.
A-176 Barriers and Enablers to Laboratory Stewardship Across a 16 Hospital Regional System
Authors: McCudden C R , Brehaut J , McCleary N
Published: September 2023

Background

Evidence indicates substantial inappropriate and inefficient use of resources in laboratory medicine. Commonly-used approaches that can be effective in improving practice include education, changes to processes or systems, and audit & feedback. The overall aims of this project were to survey the experiences of individuals implementing laboratory stewardship activities across a regional lab system, focusing on identifying key enablers and barrier to success.

Methods

We used a mixed methods approach beginning with a questionnaire to gather brief details about implementation efforts (what was done, how interventions were implemented, when, and by whom). These preliminary findings served as a precursor to conducting focus groups with implementation teams at each of the sites. We probed the implementation process, drivers of success, and barriers faced. Focus group transcripts were analyzed using thematic analysis.

Results

Forty individuals took part in the surveys and focus groups. Results revealed a range of progress with lab stewardship initiatives across sites, with a variety of initiatives having been implemented. A wide range of factors impacting progress with laboratory stewardship, both negatively and positively, were discussed. These were grouped into four broad topics: 1) Roles, responsibilities, and relationships—the “Who”; 2) Generating interest in stewardship—the “Why”; 3) Implementation strategies and processes—the “What”; 4) Project management and resources—the “How”. Key barriers identified included: lack of a clear vision which reduces relative priority, lack of resources, emphasis on financial outcomes, and that over-use problems have complex causes. Key enablers identified included active participation of hospital clinical and administrative champions, ability to implement system level changes (e.g., changing electronic orders and processes), focusing on patient safety outcomes, using established change methodologies which support systematic identification of root causes to help select appropriate change strategies as well as formal evaluation.

Conclusion

While some sites progressed with stewardship initiatives with relative ease, most faced challenges along the way. Surfacing these challenges supports the development of strategies to help address them such that lab stewardship activities can have maximal impact in improving quality of care. Structured and systematic approaches to laboratory stewardship are more likely to be successful than those without designed root cause analysis with targeted interventions and clear outcome metrics.
A-194 Intravenous Fluid Contamination of Basic Metabolic Panels Is Underrecognized by Manual Workflows
Authors: Spies N C , Farnsworth C W , Zaydman M A
Published: September 2023

Background

Erroneous laboratory results contribute to delays in diagnosis, incorrect treatment decisions, and increased healthcare costs. Of these errors, most occur in the preanalytical phase, before the sample makes it to the laboratory. One particularly common source of pre-analytical error is contamination by intravenous crystalloids (IV fluids). Current workflows for detecting IV fluid contamination rely on manual intervention by technologists, which is labor-intensive, variable between technologists, and may lack sensitivity.

Methods

9 627 320 chemistry results were aggregated. IV fluid contamination was simulated by mixing a random sample of results in silico with normal saline (NS), lactated Ringer’s (LR), and their 5% dextrose-containing counterparts (D5NS and D5LR). This simulation procedure was validated by in vitro experiments. Machine learning models were trained to predict contamination and mixture percentage using the simulated results and the prior unaffected result from that patient. A random sample of 100 predicted positives were manually chart reviewed and adjudicated. Predictions from the models on retrospective data were compared to real-world technologist flags.

Results

The ML pipeline identified 3023, 1488, 161, and 236 results as being likely contaminated with NS, LR, D5NS, and D5LR respectively (Fig. 1). Of these, 684 (23%), 84 (6%), 103 (64%), and 148 (63%) had already been flagged by technologists as contaminated. 100/100 manually-reviewed predictions were confirmed. The median contamination ratio for each fluid detected by the pipeline was lower than the current workflow for NS (95% CI of difference: −0.1 to −0.07) and LR (CI: −0.13 to −0.1). The number-needed-to-test to detect one additional contaminated specimen was 125 samples.

Conclusion

A machine learning pipeline uncovers a substantial number of potentially contaminated results that were previously undetected using manual workflows, especially among non-D5 fluids.
A-196 Trend Analysis in Proficiency Testing—Does it Work?
Authors: Bandeira A C , Banzato J M , Utiyama A H , Coutinho V F , Ramadan D R , Tufik S
Published: September 2023

Background

Trend analysis is a powerful tool in any data analysis due to its preventive characteristics. In proficiency testing (PT) it is also important because it can anticipate errors that could impact on patient’s results. Therefore, it is a key tool to patient safety. Although this is the current and logical premise, efficacy of trend analysis has not been measured by laboratories. This work aims to share our laboratory’s enhancements after implementing trend analysis for PT results.

Methods

PT results from a Brazilian national program for two years were analyzed: one year before the implementation of trend analysis (2020) and another year after the process had already been fully established (2022). Qualitative tests were not considered and a total of 432 quantitative analytes were included in the study. Trends were classified by CAP’s recommendations for single mailing patterns (Troubleshooting guide for proficiency testing data—ww.cap.org). The percentage of results classified as inadequate and inadequate results with previous trend alert were calculated. Ten results from both years were compared by Chi-square.

Results

Over 7000 results were analyzed and classified. In 2022, overall inadequate results were 37% lower than 2020. Comparing both periods, Chi-square was high (ꭓ2 = 9,74), corroborating that the enhancements observed were statistically significant. Before trend analysis was implemented, 14 inadequate results presented biased results in previous rounds. If trend analysis had not been implemented, we estimate there would be 15 analytes in this situation. However, only 5 were found, which represents a 297, 8% improvement. For this metric (inadequate results with previous trend alert), Chi-square from both periods was 5087.

Conclusion

Using a simple trend analysis technique we were able to reach an important improvement in the PT process, contributing to preventive actions for potential problems that could affect patient results and decreasing the number of inadequate results. Hence, in our laboratory trend analysis can be considered worth it.
A-201 Deriving Information from the Lipid Panel as Spherical Coordinates
Authors: Cole J , Sampson M L , Remaley A T
Published: September 2023

Background

Lipid panel assays are used to calculate LDL-C as a proxy for cardiovascular disease risk. Further investigations are required to classify the patient’s dyslipidemia into a phenotype to assist with management. We explored the information contained within the lipid panel with two aims: First, to estimate cardiovascular risk directly, bypassing LDL-C calculation. Second, to provide a novel phenotypic classification system.

Methods

Various transformations of lipid panel data were explored as inputs to a logistic regression model of cardiovascular risk, and to produce a spherical coordinate system for phenotyping. Area under the receiver operating characteristic (AUROC) curve was used to assess the predictive ability of the model. Clinical utility metrics were calculated and Kaplan-Meier survival curves were used to determine the prognostic value of the model.

Results

Transforming the lipid panel data into indices allowed derivation of a spherical coordinate system. The spherical coordinates proved to be the best input values for logistic regression to provide the probability of high cardiovascular risk. When we added age, sex and race as variables in the model, the AUROC for predicting cardiovascular events approached that of the American Heart Association’s pooled cohort equation (PCE). The final model was more sensitive than the PCE, and provided greater prognostic ability than LDL-C. The spherical coordinate system classified individuals into “normal” or one of eight phenotypes, which were differentially associated with clinical features such as elevated CRP or metabolic syndrome.

Conclusion

The new model uses all three lipid panel parameters and other routinely available laboratory data to directly predict cardiovascular risk with similar accuracy to the PCE. Conversion of the parameters to a spherical coordinate system allows classification into one of 9 phenotypic groups, which may alert clinicians to underlying or consequent pathological processes to be managed.
A-207 Analytical Validation of Helena SPIFE Touch to Determine ApoB-Containing Lipoproteins Lp(a)-P, LDL-P and VLDL-P
Authors: Scott R J , Donato L , Jaffe A , Meeusen J , Vasile V
Published: September 2023

Background

Elevated Lp(a) is an independent risk factor for atherosclerotic (ASCVD) events and associates with aortic stenosis. Accurate immunochemical measurement of Lp(a) is complicated by heterogeneity of Lp(a) molecular size. The objective of this study was to validate the analytical performance of an electrophoretic assay for measurement of ApoB-containing lipoprotein particles including Lp(a)-P, LDL-P, and VLDL-P and to compare results to other standard clinical methods.

Method

Lp(a)-P, LDL-P, and VLDL-P were quantified by electrophoretic serum separation followed by immuno-staining with an ApoB antibody using the SPIFE Touch (Helena Laboratories, Beaumont, TX). Stability was evaluated by comparison to results at time zero (n = 10). Precision was assessed by 5 measurements twice daily for five days. Limit of quantitation (LoQ) was determined by 20 replicate measurements. Linearity was assessed by mixing high and low concentrations at various ratios. Accuracy was assessed by split sample comparison (n = 126) with Helena Laboratories. Lp(a)-P and LDL-P results were compared to nuclear magnetic resonance (NMR) using a Bruker Ascend 600 NMR (Bruker, Billerica, MA) with AXINON software (numares, AG, Regensberg, Germany) (n = 114). Lp(a)-P is included with LDL-P by NMR. Therefore, the SPIFE Lp(a)-P + LDL-P was compared to NMR LDL-P. SPIFE Lp(a)-P was compared directly to Roche cobas c501 Lp(a) immunoassay calibrated to molar units (Roche Diagnostics, Indianapolis, IN) (n = 126).

Results

The analytical performance of Lp(a)-P, LDL-P, and VLDL-P measured on the SPIFE Touch met all acceptance criteria. Bias to the reference method was <20% with R2 > 0.98. All analytes were stable 14 days refrigerated and 14 days frozen. Lipoprotein particle measurements on SPIFE Touch correlated to those obtained by both NMR and Roche assays.

Conclusion

The analytical performance of the SPIFE Touch for measuring the concentration of ApoB-containing lipoproteins is acceptable. Further studies are needed to determine clinical implications and utility compared to NMR and Roche assays.
A-215 Calculated LDL-cholesterol: Comparability of the extended Martin-Hopkins,Sampson-NIH, Friedewald and four other equations in South African patients
Authors: Carelse A , Rossouw H M , Steyn N , Martins J , Pillay T S
Published: September 2023

Background

Ultracentrifugation for LDL-C (low-density lipoprotein cholesterol) measurement is the gold standard, but it is unsuitable for routine use. Direct LDL-C assays and predictive equations such as the Friedewald equation are thus used as alternatives. The Friedewald equation is known to be error-prone in hypertriglyceridaemic patients, as well as in LDL-C levels < 1.8 mmol/L (70 mg/dL) which has become increasingly attainable with the use of pro-protein convertase subtilisin/kexin type 9 inhibitors. This study evaluates the comparability of the Friedewald, extended Martin/Hopkins, Sampson/NIH and four other equations to a direct LDL-C assay to establish a suitable alternative to the Friedewald equation.

Methods

We analysed 44 194 lipid profiles from a mixed South African population. The Friedewald, extended Martin/Hopkins and Sampson/NIH LDL-C and four other predictive equations (Vujovic, Puavilai, Delong, Anandaraja) were compared to the Beckman Coulter direct LDL-C assay. Non-parametric statistics were used to analyse the data.

Results

The extended Martin/Hopkins equation displayed the best correlation with direct LDL-C, having the most values fall within the desirable bias (59%) and total allowable error (89%) specifications. In patients with TG values between 4.5 mmol (400 mg/dL) and 9.0 mmol/L (800 mg/dL), the extended Martin/Hopkins equation was more likely to overestimate LDL-C levels, showing a positive median bias of 7.3%, while Friedewald (−21.2%) and Sampson/NIH (−9.8%) showed larger negative median biases as compared to the direct LDL-C assay. The direct LDL-C assay classified 13.9% of patients in the low LDL-C (1.0–1.8 mmol/L) (39–70 mg/dL) category, in comparison to the Martin/Hopkins equation (13.4%), the Sampson equation (14.6%) and the Friedewald equation (16.0%). The extended Martin/Hopkins equation performed better than Sampson/NIH equation in the cohort.

Conclusion

We suggest the extended Martin/Hopkins equation as an alternative to Friedewald’s equation and direct LDL-C assay. Careful consideration is advised as the choice of analyser platform for the lipid profile used in the equations may influence their performance.
A-218 Analytical Performance Evaluation of Lipid Panel Assays on the Atellica CI 1900 Analyzer
Authors: Kolewe K , Singh S , Tyler C , Arrode-Bruses G , Rhea-McManus J , Snyder J
Published: September 2023

Background

The Atellica® CI 1900 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 Creatinine (CREA_2)*, Enzymatic Creatinine (ECre_3)*, Urinary/Cerebrospinal Fluid Protein (UCFP)*, and Microalbumin_2 (µALB_2)* assays on the Atellica CI 1900 Analyzer*.

Methods

The Atellica CI 1900 CH CREA_2, ECre_3, UCFP, and µALB_2 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 1900 Analyzer. Precision studies were performed according to CLSI EP05-A3 using native and contrived human urine samples. One aliquot of each sample pool was tested in duplicate in two runs per day >2 h apart on each analyzer for >20 days. MC studies were performed according to CLSI EP09-A3. Individual native and contrived human urine samples were analyzed using the Atellica CH assays on both the Atellica CH and Atellica CI 1900 Analyzers.

Results

Representative precision and MC results observed from one reagent lot across indicated sample ranges are listed for each assay in the table below. Over the four assays tested, repeatability and within-lab %CVs were <5.1% and <6.0%, respectively. Slopes determined by the Deming linear regression model were approximately equal to 1.

Conclusion

Evaluation of the Atellica CH CREA_2, ECre_3, UCFP, and µALB_2 assays using the Atellica CI 1900 Analyzer demonstrated good precision and equivalent performance compared to the same assays on the Atellica CH Analyzer.

*The products/features mentioned here are not commercially available in all countries. Their future availability cannot be guaranteed.
A-223 Lipoprotein (a) Profile in Patients with Diabetes and Coronary Artery Disease
Authors: Castelo M C , Fernandes V O , Lima Verde J L , Ballalai M S , Montenegro A D , Montenegro R M , Lopes A C
Published: September 2023

Background

Changes in the lipid profile that cause an increase in cardiovascular risk are basically those that occur with an increase in apolipoprotein B-100 (apoB). This lipoprotein is present in LDL, VLDL, IDL and lipoprotein a or Lp(a). Lp(a) is a molecule similar to LDL being formed by the junction of apoB with apolipoprotein A. Lp (a) levels are virtually independent of diet or environmental factors. Around 90% is defined by the patient’s genetic heritage. Lp(a) has the potential to cause atherosclerosis by LDL-like mechanisms (vascular wall impairment, oxidation), However, there are several other mechanisms that are proposed to explain the increased cardiovascular risk caused by increased Lp(a) levels. Some would result in a high risk of thrombogenicity, others of atherogenesis. The aim of this study was to describe the Lp(a) profile in individuals with diabetes and coronary artery disease.

Methods

This is a descriptive cross-sectional study carried out in 2 reference centers in the care of patients with diabetes and high cardiovascular risk in Fortaleza-Ceará, Brazil.We evaluated lp(a) level was and the presence of multivessel coronary artery diseaseThe statistical analysis of the data was performed with the Microsoft Excel program.

Results

Of the 34 patients evaluated, 47% (16) were male and 53% (18) female, with a mean age of 58.3 ± 9.34 years old, The mean time that the coronary event had occurred was 7.85 ± 6.27 years, and the mean age at the first thrombotic event was 51.56 ± 9.311 years old. There was found 44.1% of dyslipidemia before the first thrombotic and 61.7% had multivessel coronary artery disease. Lp(a) median was 23.5 mg/dL (min < 3-max 149).70.5% of the evaluated patients had Lp(a) < 50 mg/dL, 20.5% between 50–90 mg/dL, and 8.8% had Lp(a) > 90 mg/dL.

Conclusion

Most patients with diabetes studied had normal or subnormal levels of lp(a) even though they were patients at very high cardiovascular risk. More studies need to be carried out, but this finding could suggest that in diabetic individuals, as well as LDL-c, we could have lower cutoff points than in the general population.
A-257 Association Between Matrix Metalloproteinase-3 and its Post-Transcriptional Regulator miR-17-5p in the Pathogenesis of Tuberculous Meningitis Patients
Authors: Aggarwal A , Sharma S R , Modi M , Sharma K , Verma I , Singla N , Konar M , Kaur M , Sharma K
Published: September 2023

Background

Tuberculosis, a communicable disease caused by Mycobacterium tuberculosis is one of the top 10 causes of death worldwide. Tuberculous meningitis (TBM), an extra-pulmonary central nervous system tuberculosis is the most severe form with maximum mortality. To combat the complications of disease, host immune response gets activated which initially protects the host but later an exaggerated response leads to aggravation of the disease. This causes tremendous neuroinflammation which further increases the complications of the disease. Matrix metalloproteinase (MMPs) like MMP-9, 2 and 3 are known to cause damage to the blood brain barrier and have a role in the pathogenesis of disease particularly increasing the neuroinflammation. MMPs are regulated at post-transcriptional level by microRNAs (miRNA) that alter their levels by targeting various genes. Based on available literature we found miR-17-5p to be a key regulator of MMP3. In this study, we assessed the levels of MMP3 and its post-transcriptional regulator miR-17-5p in the cerebrospinal fluid (CSF) of TBM patients, healthy controls (HC) and non-infectious neuroinflammatory disease patients (NID).

Methods

In this study, 100 TBM patients were recruited based on the Lancet scoring system and CSF samples were collected. For NID control group, 25 patients with other non-infectious neuroinflammatory diseases like Guillain-Barre syndrome, multiple sclerosis were recruited. Twenty five HC CSF samples were collected from patients undergoing spinal anaesthesia for any lower limb surgery. The samples were stored at −80°C and processed when required for ELISA and quantitative real time PCR.

Results

We found a significant increase in levels of median MMP3 levels in the CSF of TBM patients compared to HC group (2.719 ng/ml vs 1.696 ng/ml). The MMP3 levels were also significantly elevated in the NID control group as compared to HC group (3.116 ng/ml vs 1.696 ng/ml). A stagewise comparison in TBM group showed an increase in levels of MMP3 with respect to HC but within stages results were comparable. The expression of MMP3 regulator miR-17-5p showed an upregulation in the CSF of TBM group as compared to NID and HC group.

Conclusion

An increase in levels of MMP3 was observed in both TBM and NID group which infers that MMP3 might have a role in neuroinflammation in neurological conditions. In our study groups we did not find any relation between miR-17-5p expression and MMP3 levels, indicating that there might be some other regulatory pathway altering the levels of MMP3 in neurological conditions. Hence, further studies can be done to highlight the explicit role of MMP3 in neuroinflammation which can then be targeted therapeutically to relieve the associated complications.
A-282 Coinfection Rates of SARS-CoV-2, Influenza, and Respiratory Syncytial Virus
Authors: Pratt G W , Platt M , Wong C , Rao L V
Published: September 2023

Background

In late 2022, a severe spike of respiratory syncytial virus (RSV) cases in the United States alongside seasonal influenza and the ongoing SARS-CoV-2 crisis underscored the potential consequences for respiratory coinfections. Coinfections of respiratory viruses can complicate treatment and increase the likelihood of severe cases. It is not well understood how prevalent respiratory coinfections were during this time in the general and pediatric populations. In this retrospective analysis we examine respiratory molecular diagnostic testing results to estimate the rates of coinfection in the study population.

Methods

Respiratory sample results from a clinical laboratory for a 107-day period in autumn 2022 were analyzed. Assays were performed on two platforms: the Roche cobas® SARS-CoV-2 & Influenza A/B Test and the Cepheid Xpert® Xpress CoV-2/Flu/RSV plus assay. Overall positivity and coinfection rates were calculated. Coinfection results of the pediatric population were further investigated.

Results

A total of 26 657 respiratory testing results were analyzed. Cases of coinfection of SARS-CoV-2, influenza A, influenza B, and RSV were seen. Positivity ranged from 0.03% to 21.86% and coinfection rates ranged from 0.00% to 2.28% depending upon the pathogen. Overall, 9800 samples (36.76%) came from pediatric patients (age ≤21). Pediatric positivity ranged from 0.04% to 24.70% and coinfection rates ranged from 0.00% to 6.00% depending on the pathogen (Table).

Conclusion

Overall, coinfections were observed in 0.55% of samples comprising 1.33% of all positive results. In this study population, pediatric samples accounted for a disproportionately high percentage of positive results for influenza A, RSV, and SARS-CoV-2 coinfections when compared to the overall percentages from the complete study population.
A-287 Evaluation of Urinalysis Reflex to Culture in Long-Term Care Facilities: Is It Worth it?
Authors: Khoury R , Gandhi A , Patel P , Gudaitis D , Gudaitis P
Published: September 2023

Background

Urinary Tract Infection (UTI) is one of the second common infections among the geriatric population. It is more common in women than men and the incidence increases with age. UTI can cause serious complications and it is a significant cause of morbidity and death. The high mortality rate is largely due to delayed presentation and the development of bacteremia/sepsis. Physicians rely heavily on urinalysis to diagnose UTI, and it is one of the most frequently requested tests; however, the need to reflect to urine culture became more in demand to cut the cost of test not needed without the sacrificing of patient care.

Methodology

4307 urine samples were collected for urinalysis and culture from residents in Long-Term Care Facilities (LTCF) over a period of 5 weeks. Urinalysis and microscopy were done using IQ WORKCELL automated system. All the specimens were cultured; the culture was done using MicroScan Walkaway96 conventional panels. We used urine culture as the reference standard, no growth or <10 000 colony-forming unit/mL were considered negative, cultures with >50 000 colonies colony-forming unit/mL were considered positive. UA is considered positive if it was positive leukocyte esterase, WBC > 5, nitrate, or had >moderate bacteria. We compared positive UA to the culture outcome. Statistical analyses were done using Analyse-it.

Results

Women represented 64.7% of the samples tested; the positivity rate was 49.2% (52.3% for women and 43.4% for men) and 7.0% of the all the cultures had mixed flora. Urinalysis identified 3038 as positive UA, only 1941 (63.9%) had positive culture and 846 (43.6%) had negative culture. Urinalysis identified 1269 samples as negative, 176 samples (13.9%) of them had positive culture.

Conclusion

The use of negative urinalyses to reflex to culture would help eliminating the majority of the cultures that are not necessary. However, avoiding the culture will risk missing infection in 13.9% of the negative urinalysis samples. In addition, more than one third of the positive urinalysis will require unnecessary cultures. Although the use of reflex will help eliminating the unnecessary culture, we have to remember that urinalysis and microscopy still lack the sensitivity and specificity to be used alone to diagnose urinary tract infection; urinalysis should not be the only marker for UTI, it should be used in conjunction with patients clinical diagnosis. The high positivity rate for UTI in LTCF adds to the complication of the reflex testing. More work needed to establish better parameters and algorithm to be used when screening patients for UTI using urinalysis.
A-289 Emergence of Unusual Non-Fermentative Gram-Negative Bacilli Associated to COVID-19 Period at Brazilian Hospitals
Authors: Nurmberger J M , Inoue F M , Lobo A T , Ramadan D R , Tufik S
Published: September 2023

Background

Since the global pandemic of coronavirus disease (COVID-19), some studies have reported on the emergence of opportunistic nosocomial pathogens associated with co-infection on the outcome of COVID-19 patients. The aim of this study was to describe the increase of six unusual species of Non-fermentative Gram-negative bacilli (NF-GNB) clinical isolates recovered from inpatients in several Brazilian hospitals comparing pre-Covid-19 (January 2018 to December 2019) period vs Covid-19 (January 2020 to December 2021) period.

Methods

This study design was a retrospective, observational analysis based on microbiological data of emergent NF-GNB isolates, detected in several Brazilian tertiary hospitals. The bacterial identification was performed by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF/MS) and the susceptibility of antibiotics was determined using disk diffusion method.

Results

During the 48 months period, a total of 1665 (2018; 349), (2019; 351), (2020; 485), (2021; 480) emergent NF-GNB isolated from blood (n = 744), respiratory tract (n = 239), skin and soft tissue (n = 264); urine (n = 119), catheter (n = 101), fluid and secretions (n = 113), Cerebrospinal fluid (n = 12) and others (n = 73) were analyzed. The frequency of NF-BGN according to species level identification was Stenotrophomonas maltophilia (1040; 62.5%), Burkholderia cepacea complex (457; 27.4%), Elizabethkingia meningoseptica (64; 3.8%), Elizabethkingia miricola (31; 1.8%), Ochrobactrum anthropi (69; 4.1%) and Ochrobactrum intermedium (4; 0.2%). The prevalence of these NF-BGN detected in pre-Covid-19 period (2018–2019) and Covid-19 period (2020–2021) were 42% and 58%, respectively. The incidence of Stenotrophomonas maltophilia, Burkholderia cepacea complex, Elizabethkingia spp. and Ochrobactrum spp. infection was (47.7% and 52.3%), (42.9% and 57.1%), (43.2% and 56.8%) and (50.7% and 49.3%) among female and man patients, respectively. For Stenotrophomonas maltophilia, Burkholderia cepacea complex and Ochrobactrum spp. the main age range was over 60 years (44.5%, 44.9% and 42.5%) while for Elizabethkingia spp. the main age range was 0–10 years of age with 42.5% of cases in the pre-COVID-19 period and over 60 years old with 43.9% in the COVID-19 period. Compared the two periods (2018–2019 vs 2020–2021) for Stenotrophomonas maltophilia the resistance rate to levofloxacin and sulfamethoxazole-trimethoprim was (3.9% vs 4.6%) and (4% vs 4.2%), respectively.

Conclusion

Our data point to a scenario wherein the presence of opportunistic pathogens may have been intensified by the covid-19 pandemic. Further studies should be carried out to clarify these findings.
A-330 Trending Treatment of Transplant-associated Thrombotic Microangiopathy (TA-TMA): Validation and Performance of Soluble C5b-9 on the Dynex DS2 Platform
Authors: Wilson R J , Johnson L M , Bhandari M , Dickerson J A
Published: September 2023

Background

The complement system membrane attack complex is comprised of the C5b fragment along with C6, C7, C8 and C9 polymers that form a pore to disrupt a membrane during complement activation. Inactive complexes that are not membrane-bound combine with Protein S to form soluble C5b-9 (sC5b-9). Elevated concentrations of sC5b-9 are associated with risk of development of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA), which can be treated by eculizumab therapy. TA-TMA is a complex syndrome of abnormal cell activation, microvascular hemolytic anemia, and complement dysregulation which can lead to multiple organ dysfunction and death. Therefore, recognition of this syndrome is critical in the context of not only preventing poor outcomes in patients but also promoting stewardship of an expensive, yet effective therapy. Our laboratory evaluated the performance of the Quidel Microvue sC5b-9 Plus enzyme immunoassay on the Dynex-DS2 platform for clinical use.

Methods

EDTA plasma samples were collected from remnant CBC samples ordered for bone marrow transplant (BMT) patients and other patients not at risk for TA-TMA. Validation studies included method correlation, inter- and intraday precision, assay linearity, hemolysis interference, and other experiments. Clinical accuracy was assessed by performing a retrospective review of sC5b-9 results from BMT pediatric patients at risk for TA-TMA.

Results

Intraday precision was 6.7%, 7.1% for the manufacturer low- and high-quality control materials, respectively and 9.9% for an in-house prepared plasma pool. Inter-day precision was 9.8% and 5.3% for manufacturer low- and high-quality control material, and 12.8% for an in-house plasma pool over a period of at least five days. The linearity of the assay was verified with a lower limit of quantification of 80 ng/mL and upper limit of qualification of 1600 ng/mL. Our method comparison indicated good correlation with send-out results, with an average percent bias of -10% and Pearson's r2 value of 0.986. The assay showed no interference up to 100 mg/dL of hemolysis. Retrospective analysis of a few patient results demonstrated that weekly monitoring of sC5b-9 concentrations detected rapid increases in patients at risk of TA-TMA, which prompted treatment with eculizumab therapy. Given the analytical performance, at least 2- to 3-fold changes in sC5b-9 concentrations are clinically meaningful when tracking trends in patients at risk for TA-TMA.

Conclusion

Our results indicate the Quidel Microvue sC5b-9 Plus enzyme immunoassay on the Dynex-DS2 platform had acceptable analytical and clinical performance for monitoring trends in patients at risk for TA-TMA.
A-357 Performance of Blood Urea Nitrogen on the epoc Analyzer
Authors: Dilks M , Evans L M , Goldsmith B M
Published: September 2023

Background

The epoc Blood Analysis System (Siemens, Tarrytown, NY) performs blood gases, electrolytes, and metabolites using a Blood Gas Electrolyte and Metabolite (BGEM) Test Card panel on 92 uL of whole blood. The BGEM Test Card uses potentiometric sensors to measure sodium, potassium, chloride, ionized calcium, pH, pCO2; amperometric sensors to measure pO2, glucose, creatinine, and lactate; and a conductometric sensor to measure hematocrit. Results are available in 3–10 minutes, depending upon the time of sample injection. TJUH implemented the epoc in its ICUs in 2012 to provide rapid, whole blood Point of Care (POC) results, then expanded to other locations (Emergency Department, Outpatient Radiology, Cardiothoracic Surgery). Siemens recently added a potentiometric sensor for measurement of Blood Urea Nitrogen (BUN) to its BGEM card. We evaluated this card for possible future use.

Methods

Precision and method comparison studies were performed at our Center City location. Inter- and intra-precision studies were performed on two levels of controls (Eurotrol, Elizabethtown, KY). Remnant whole blood was collected from 30 patients. Comparison studies were performed on the Piccolo Xpress (Abbott, Princeton, NJ), which provides a whole blood BUN measurement using a coupled-enzyme reaction.

Results

Intra-assay precision for epoc BUN (n = 20, 2 devices) was 2.8%CV and 6.5%CV for Levels 1 and 3, respectively. Inter-assay precision for epoc BUN (n = 20, 2 devices over 10 days) was 2.4%CV and 7.1%CV for Levels 1 and 3, respectively. Method comparison for BUN (n = 30) was: mean = 42, median = 29, r2 = 0.9889, y = 0.8840x-3.6416.

Conclusion

The epoc BUN studies showed comparable results when compared to the Piccolo Xpress. Previous studies showed good correlation between whole blood on the Piccolo Xpress and plasma on the Roche Cobas c702 which is also a coupled-enzyme reaction; therefore the test is considered acceptable for implementation at our Center City sites where epoc is currently in use.
A-367 Development of a Novel Handheld Platform for Real-time Fluorescence-based Nucleic Acid Detection
Authors: Hong Y , Song Q , Gao Y , Liua Y , Wen W
Published: September 2023

Background

Real-time fluorescent nucleic acid detection systems are usually large and complex to operate. In the past three years, the pandemic outbreak of COVID-19 has sparked a variety of point-of-care testing (POCT) nucleic acid detection platforms. However, most of these platforms need to be paired with specific reagents, and many detection reagents on the market cannot be applied to these POCT platforms.

Methods

In this research, a novel handheld real-time nucleic acid detection device was invented. The device uses a heating element to adjust the temperature in time with a sensor to ensure accuracy. The optical detection module is highly scalable and can be extended up to 6 fluorescence channels. The FAM and HEX fluorescence channels were utilized in this experiment. This platform is open and can adjust temperature for various types of isothermal nucleic acid detection, such as LAMP, RPA, and RCA.

Results

We used a commercial COVID-19 reagent kit with our device to get results in just 30 minutes, detecting SARS-CoV-2 virus as little as 500 copies/mL. Our system provides a reliable and efficient tool for COVID-19 testing in a variety of settings.

Conclusion

The handheld device was also used to test for flu A and mycobacterium tuberculosis, with good results. This device can be used not only for pathogen detection of human diseases, but also in pathogen detection for animals and plants, food safety, environmental monitoring, and other fields, thus expanding the application range of nucleic acid detection and making it simpler and more convenient to use.
A-382 Evaluation of the Labcorp TrueSpinTM for Decentralized Blood Sample Centrifugation
Authors: Iacovetti G , Collier B , Setzer S , Peevler M , Ragar J , Brandon W , Chappell M , Grant R P , Sommer G J , Schaff U Y
Published: September 2023

Background

The increased demand for decentralized blood sample collection presents numerous operational challenges for diagnostics providers. Sample degradation including sample hemolysis due to time, temperature, and handling between collection and laboratory analysis leads to limited test menus and unreliable results. Here we evaluate the light-weight, portable Labcorp TrueSpin™ for rapid point-of-care blood separation using commercially available microvolume blood collection tubes. The TrueSpin is a class I FDA registered device designed for layperson use. The centrifuge runs on AA batteries and separates a blood sample in five minutes.

Methods

Here we show results of studies evaluating sample quality and analyte stability in serum samples collected into gel microtubes and processed using the TrueSpin. Hemolysis and residual red blood cell (RBC) concentration are compared between samples separated using the TrueSpin and conventional centrifugation. Additionally, we evaluate serum-based chemistry analyte stability in both separated and unseparated samples stored for three days refrigerated and unrefrigerated.

Results

No significant difference was seen in hemolysis or residual RBC concentration in serum samples prepared by TrueSpin compared to the reference centrifuge method. Furthermore, we show that many common serum-based chemistry analytes have limited (<1 day) stability if uncentrifuged, but improve to ≥3-day stability following TrueSpin separation and refrigerated or room temperature storage (see Table 1).

Conclusions

These findings suggest that the TrueSpin is a simple and effective solution for remote sample separation and may enable broader test menus and increased test result reliability for decentralized sample collection pursuits.
B-005 Blood pH and Phosphate Tend to Follow an Inversely Correlated Homeostatic Status
Authors: Islam S , Osa-Andrew B , Cao J , Muthukumar A R , Jones P M , Hashim I
Published: September 2023

Background

Phosphorus containing biomolecules perform an essential biochemical function in maintaining extra and intracellular acid-base status. Maintaining normal concentration (2.5–4.5 mg/dl) of phosphorus is indispensable for optimal cellular function and homeostasis. Serum concentration of phosphorus (mainly inorganic orthophosphates) is an indicator of H2PO4−/HPO42− acid-base buffer condition. Disturbance of pH could be an immediate impact of many respiratory and metabolic morbidities. Extra/intracellular redistribution of phosphates in response to an abnormal pH is an established homeostatic phenomenon. Failure to maintain an appropriate phosphate level to support the extra/intracellular redistribution may result in a pH shock. Therefore, it is important to have a clear understanding on how blood phosphate and pH levels are interconnected which could assist in guiding therapeutic interventions to fix phosphate abnormalities and acid-base disturbances. This study examined the homeostatic correlation between blood pH and phosphate level among hospitalized and ambulatory patients.

Methods

Serum phosphorus concentration and pH were retrieved from the biochemical profiles and arterial blood gas data of hospitalized and ambulatory patients who presented or admitted our tertiary care level university hospital during the first week of July, 2021. Logarithmic (base ten) values of phosphorus concentration were determined to normalize the distribution of the phosphorus data more uniform. Correlation analyses between phosphorus/log[phosphorus] and pH were performed by GraphPad PRISM version 8.

Results

A total of 101 corresponding blood gases and phosphate levels were obtained. Both phosphorus and log [phosphorus] values of the patients displayed an inverse correlation with arterial pH (Figure 1a and b). Pearson r values demonstrated a negative correlation between phosphorus/log [phosphorus] and pH (−0.6737 and −0.6450, respectively).Fig. 1.

Conclusion

Monitoring of phosphate levels provide an early indication of acid base status. Phosphorus level maintains an inverse correlation with pH profile. Therefore, a therapeutic manipulation of phosphorus or pH may have a mutual effect requiring further investigation.
B-021 Analytical Performance of Thyroid Function Test on DxI800 System
Authors: Jang J , Kang H , Jang H , Rim J , Lim J
Published: September 2023

Background

Thyroid function tests (TFT) which usually include thyroid stimulating hormone (TSH), total triiodothyronine (TT3), and free thyroxine (FT4) are widely applied in clinical practice for screening, diagnosis and monitoring of thyroid disease. We evaluated analytical performance of TSH, TT3, and FT4 using DxI800 (Beckman Coulter, USA) including comparison to Alinity I (Abbott, USA).

Methods

Precision was determined by percent coefficient of variation (%CV) measuring low, medium, and high levels of quality control material for 5 days with one run per day, 5 replicates per run. Linearity was evaluated using 5 levels of patient serum samples and concentrations were determined by the mean value of two replicates of each level. Method comparison was performed by Passing-Bablok regression using 40 patient serum samples.

Results

The within-run imprecision at low, medium and high level were 1.50%, 1.77%, and 2.59% for TSH; 4.10%, 2.45%, and 2.84% for TT3; and 3.23%, 2.76%, and 2.19% for FT4. The within-laboratory imprecision at low, medium, and high level were 1.61%, 1.91%, and 2.87% for TSH; 4.33%, 3.73%, and 3.70% for TT3; and 3.36%, 2.76%, and 2.20% for FT4. Linearity of TFT on DxI800 was demonstrated in the range of 0.01–44.68 µIU/mL, 0.09–7.40 ng/mL, and 0.18–5.52 ng/dL for TSH, TT3, and FT4, respectively. Method comparison between DxI800 and Alinity I showed a slope of 1.21 and intercept of 0.05 (correlation coefficient R = 0.994); a slope of 0.95 and intercept of 0.13 (correlation coefficient R = 0.971); and a slope of 1.81 and intercept of −0.88 (correlation coefficient R = 0.969) for TSH, TT3, and FT4, respectively.

Conclusion

DxI800 showed acceptable performance in terms of precision and linearity for TFT assay including TSH, TT3, and FT4. This study demonstrated that TFT on DxI800 are suitable in clinical laboratory.