bluuebunny/crossref_metadata_2025 huggingface dataset:
A-014 Analytical Outlier Occurrence and False Positivity Rate of the Beckman Coulter Access High-sensitivity Cardiac Troponin I Assay
Authors: Noguez J H , Delfin Mendez L , Kulp K , Zhang X , Stempak L
Published: September 2023

Background

Cardiac troponin (cTn) is the preferred biomarker for the diagnosis of acute myocardial infarction due to its high sensitivity and specificity relative to other available cardiac markers. Accurate measurement is therefore paramount to proper risk stratification of patients. Analytical outliers and false positive results have been previously reported on various platforms though the exact cause remains unknown. These false positive test results may pose a risk for the misclassification of patients and lead to adverse clinical outcomes. We evaluated the performance of the Beckman Coulter Access high-sensitivity cTn I method by measuring the occurrence of analytical outliers between duplicate results and the false positivity rate (i.e., fliers).

Methods

We tested 2535 samples from 1879 patients in duplicate on the Beckman Coulter Access hs-cTn I assay. These specimens had initial troponin measurements above the gender-specific 99th percentile of the upper reference limit (URL) cutoff and were immediately aliquoted, re-centrifuged, and re-tested. Non-reproducible results (outliers) were defined as having a concentration difference between the replicates exceeding 10%. Critical outliers were defined as duplicate results with concentrations that differed by greater than 10% from the initial result and the second result was classified in a lower risk stratification category than the original result.

Results

Approximately 12% (305) of the positive samples tested in duplicate had a percent difference that was >10% and therefore did not meet the recommended precision requirements of the assay. Of these specimens, 33 (10.8%) were classified as critical outliers because the repeat test result crossed a critical decision limit threshold. For sixteen samples the risk classification for the patient was downgraded from high (>50 ng/L) to moderate risk (13–50 ng/L (F); 20–50 ng/L (M)). Seventeen false positive results were identified in which the patients were downgraded from the high to low risk category (<13 ng/L (F); <20 ng/L (M)). Nearly 85% of the samples identified as outliers were lithium heparinized plasma.

Conclusion

We evaluated the reproducibility of the Beckman Coulter Access hs-cTn I method across 11 hospitals in an integrated healthcare network to characterize the occurrence of analytical outliers and false positive results. Our data indicated an outlier rate of 12% (305/2535) for positive hs-cTn I results; however, the risk category only changed for 1.3% (33/2535) of positive troponin results upon repeat analysis. Overall the false positivity rate was determined to be <0.1% (n = 55 560).
A-040 Night Shift Work Could Induce Oxidatively Generated Damage to DNA: A Pilot Study
Authors: Zou Y , Ma X , Yu S , Qiu L
Published: September 2023

Background

Currently, specific effects of different night shift modes on human oxidative stress still need to be explored in a realistic cohort study. We aimed to evaluate the effect of night shift on human nucleic acid damage status.

Methods

We recruited 16 healthy volunteers (aged, 33 ± 5 years) working the night shifts at the Department of Laboratory Medicine at Peking Union Medical College Hospital. Their matched serum and urine samples were collected at four time points: before, during (twice), and after the night shift period. The levels of 8-oxo-7,8-dihydroguanosine (8-oxoG) and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), two important nucleic acid damage markers, were accurately determined based on a robust self-established LC-MS/MS method. The Mann–Whitney U or Kruskal-Wallis test was used for comparisons.

Results

The levels of serum 8-oxodG, estimated glomerular filtration rate corrected serum 8-oxodG, and 8-oxodG in serum to urine ratio significantly increased during the night shift period. These levels were significantly higher than at baseline even after 1 month of discontinuing; but no such significant change was found for 8-oxoG. Moreover, 8-oxoG and 8-oxodG levels revealed a significantly positive association with many routine biomarkers such as total bilirubin and urea levels, and significantly negative association with serum lipids such as total cholesterol levels.

Conclusion

The results of our cohort study suggested that working the night shifts may increase the oxidatively generated damage to DNA even after a month of discontinuing night shift work. Further studies with large-scale cohorts, different night shift modes, and longer follow-up times are needed to clarify the short- and long-term effect of night shifts on DNA damage, and find effective solutions to combat the negative effects.
A-047 Role of the Gut Microbiota in the Efficacy of Dietary Intervention With Flavonoid-Containing Foods in Obesity
Authors: Alqudah S , DeLucia B , Osborn L , Markley R , Bobba V , Hamidi Nia L , Claesen J
Published: September 2023

Background

Flavonoids are an active component of plant-based diets that have been investigated for their beneficial antioxidant properties in high fat diet induced obesity animal models and human intervention trials. Certain bacterial members of the gut microbiota have been reported that transform flavonoids into monophenolic acids. Our goal is to characterize the microbiome link between a flavonoid-rich diet and improved metabolic parameters characteristic of obesity. We hypothesize that flavonoid supplemented diets are most effective in presence of microbiota capable of monophenolic acids formation, and that these bacterial metabolites are a main bioactive compound responsible for the improved metabolic parameters.

Methods

To test our hypothesis, males and females C57BL/6 mice were fed a high fat control diet, or the same diet supplemented with 1% berry extract, or 1% monophenolic acid for 12 weeks. Separate experimental groups received either regular drinking water or antibiotic water to suppress their gut microbial community. We monitored metabolic parameters, including body weight, lean and fat mass, glucose and insulin tolerance, histological assessment of liver cell, quantification of liver injury biomarkers, and transcriptional changes in metabolically active peripheral tissues.

Results

For insulin tolerance test, mice on high fat diet with regular water, or antibiotic water control mice had a comparable increase in insulin resistance, demonstrated by the increase in glucose levels after injecting insulin. Similarly, the groups of mice on high fat diet with 1% monophenolic acid and regular water, or antibiotic water, had improved insulin sensitivity, presented as a decrease in glucose levels after insulin injection. Consistent with our hypothesis, mice on high fat diet supplemented with 1% berry extract had an improved insulin sensitivity, and this effect was dependent on an intact microbiome. This suggests that the gut microbiota are required to metabolize the berry extract to produce bioactive metabolites that improve insulin tolerance. We also observed a significant decrease in fasting blood glucose, an improvement in the expression for genes involved in lipid and glucose metabolism, and a noticeable reduction in hepatic steatosis in both 1% monophenolic acid and 1% berry extract with high fat diet group, compared to the high fat diet control group.

Conclusion

By feeding the mice a flavonoid rich diet, with the presence of an intact gut microbiota, we can improve the metabolic parameters associated with metabolic diseases. Our work will open the door for new benign approaches for treatment, such as dietary flavonoid supplementation with concomitant gut microbial probiotic therapy.
A-059 Evaluation of Free Thyroxin Levels in Patients with Low Thyroxin Binding Globulin Concentrations: Is There Interference in the FT4 Indirect Method?
Authors: Pinheiro M F , Lopes A C , Souza T S , Fontes R , Schrank Y , Perozo A F , Gomes D M , Araujo P B
Published: September 2023

Background

Thyroxine-binding globulin (TBG) is the major carrier of thyroid hormones in serum. Variations in the serum concentration of TBG determine proportional variations in the total serum concentrations of T4 and T3, without implying changes in function, as long as the free fraction remains normal. Several common clinical conditions lead to significant alterations in TBG levels, the most important factor behind low levels being genetic defects. As TBG is encoded by a gene located on the X chromosome, the defects are more easily manifested in males. Differences in FT4 concentrations were observed in sera from subjects with TBG abnormalities, when FT4 are measured by different immunoassays, specially at extremes of TBG concentrations. The objective of this study was to evaluate FT4 levels by indirect method in patients with low TBG concentrations.

Methods

We analyzed blood samples requesting serum TBG, TSH and FT4 levels from patients admitted to a private reference clinical laboratory in Brazil, from January 01, 2017 to December 31, 2022. Anonymized data on laboratory tests was available from a database of the local Laboratory Information System. All the patients included had TSH within the reference range, 0.4–4.3 mUI/mL (ECLIA, Modular, Roche). FT4 was measured by ECLIA (0.7–1.8 ng/dL) and TBG by ICMA, Immulite, Siemens, 13–39 mcg/mL.

Results

357 patients with low TBG levels were evaluated, 220 (62%) men, 137 (38%) women; mean age 35 yrs (19 d to 88 yrs). They were divided in six groups according TBG levels (mcg/mL): <3.5–17 (M 15, F2); 3.5 to 6.0 - 26 (M 20, F 6); 6.1 to 8.0 - 30 (M 25, F 5); 8.1 to 9.9 - 59 ( M 32, F 27); 10.0 to 11.9 - 139 (M 78, F 61); 12.0 to 12.9 - 86 (M 50, F 36). Three patients had FT4 levels above 1.8 (1.85; 1.87 and 1.96) ng/mL, all them male, with TBG levels <3.5; 5.79 and 9.53 ng/mL, respectively.

Conclusion

FT4 Indirect methods are developed taking into account the presence, in the serum, of a thyroxine binding capacity within the normal range, a fact that does not occur in individuals with extreme TBG deficiency. In this study, we found only one slightly elevated FT4 value among 17 patients with TBG values below 3.5 mcg/mL, suggesting little interference of very low TBG levels in this indirect free T4 method.
A-086 Vitamin D and its Variation in a Pandemic Context: Pre-pandemic—Intra-pandemic—Post-pandemic Analysis in the Province of Buenos Aires - Argentina
Authors: Canala P N , Canala M D , Spiccia M , Ghioni G
Published: September 2023

Background

The determination of 25 OH Vitamin D3 is a frequently requested measurement for the purpose of evaluating its deficiency, which would be related to various diseases. The behavior of monthly mean values (X̅) was analyzed in 984 514 patients from Buenos Aires (Argentina) in the period from January 2014 to December 2022, in order to evaluate how seasonality influences and verify the effect of the mandatory isolation due to the SARS-CoV-2 virus pandemic in 2020.

Methodology

We used the Chemiluminescence Assay (QLIA) ADVIA Centaur Vitamin D Total Assay (Siemens) on an Advia Centaur (2014–2020) and Aliniti I 25 OH VITAMINE D3 (Abbott Diagnostics) on an Aliniti I (2020–2022), reference values are Optimal: >30.0 ng/mL, Insufficiency: 20.0–30.0 ng/mL Deficiency: <20.0 ng/mL.

Results

Conclusions

From the analysis of the data, a decrease in the winter months is observed, as already described, caused by less exposure to sunlight. In 2020, it was also observed that due to confinement, there was a slight increase in mean values (26.40 ng/mL (P < .001)), which was the highest of the years analyzed. One hypothesis is that this could be caused by the increased free time of the population resulting in greater exposure to sunlight. At the same time, the insufficiency of Vitamin D3 in the studied population is evident, as only in 2 out of the 108 months analyzed did it slightly exceed the optimal level of 30.0 ng/mL. We believe that it would be important to evaluate the implementation of a Vitamin D3 supplementation policy for the general population and subsequently conduct further studies of this type to verify the effectiveness of such implementation.
A-141 Evaluation of the Novel Blood Coagulation Analyzer S400CF Comparison on Basic Performance and Turnaround Time With the CP 3000
Authors: Abe Y , Uchida K , Munekata S , Kanoh Y
Published: September 2023

Background

Coagulation and fibrinolytic tests are widely used as screening of abnormalities on hemostatic mechanisms, and for thrombosis. Our laboratory routinely receives large number of orders for coagulation and fibrinolytic tests. The monthly average of order is 9700, and these orders are reported as emergency tests. To address the demands, fully automated blood coagulation analyzers that offer a variety of measuring principles such as coagulation time method and photometric method. We have operated three units of the automated blood coagulation CP3000 for eight years. In this eight years, the number of samples in our hospital has been increased. On the other hand, our preparation time before daily set-up has been extended because of the stricter management on quality control to comply with ISO 15189. As a result, we need to do the same procedure on three units and our turnaround time (TAT) has been extended. In November 2021, the blood coagulation analyzer S400CF that offers high throughput and performance was launched. We evaluated basic performance of S400CF and TAT and compared with the CP3000.

Methods

In the evaluation of basic performance, S400CF (Sekisui Medical) and was used. Correlation was compared with CP3000 (Sekisui Medical). In the comparison of TAT, three units of CP3000 and one unit of S400CF were used and the orders corresponding for the 243 samples that were requested by 7:45 AM–10:08 AM on July 11, 2022 were demonstrated on both analyzers.

Results

Repeatability:C.V.% 2% or less for all items. Between-day precision: C.V. 8% or less for all items. Correlations were PT-% (N = 135): Y = 1.0477 X − 6.40, PT-INR (N = 135): Y = 0.9612 X + 0.046, APTT (N = 124): Y = 1.0150 X + 0.42, Fbg (N = 112): Y = 1.0284 X + 2.4, AT (N = 52): Y = 0.9700 X, FDP (N = 49): Y = 0.9326 X + 0.06, DD (N = 80): Y = 1.0322 X + 0.279, SF (N = 50): Y = 1.0423 X − 1.73. TAT of CP3000 and S400CF were MIN 1 minutes(min.) 41 seconds(sec.), MAX 14 min. 45 sec. and MIN 1 min. 20 sec., MAX 12 min. 27 sec., respectively.

Conclusion

It was indicated that one S400CF has three times or more productivity of CP3000. Therefore, the number of blood coagulation analyzers can be reduced from the current three units. And the total time for quality related process such as calibration and control can be saved.Results were equivalent to current CP3000 or better. It indicates that the quality of our current test can be maintained. S400CF has a capability to connect laboratory automation system that saves the time for placing specimen and improves the working efficiency of laboratory technicians. We concluded S400CF can solve the problems in our current operation in blood coagulation test and can contribute to faster report of high-quality test results.
A-198 Acute Effects of a Single Moderate-intensity Exercise on Omega-3 and Omega-6 Metabolic Pathway Using Whole Blood Lipidomics
Authors: Sakane N , Suganuma A , Sakane S , Fujibayashi M
Published: September 2023

Background

Omega-3 fatty acid supplementation can reduce muscle soreness and maintain muscle function following eccentric exercise-induced muscle damage. However, the relationship between the dietary and biological status of omega-3 fatty acids in rugby players is unknown. This study aimed to examine the relationship between the dietary and biological status of omega-3 fatty acids in university rugby players. We investigated acute effects of a single moderate-intensity exercise on omega-3 and omega-6 metabolic pathway using whole blood lipidomics.

Methods

A cross-sectional study of university rugby players and age-matched sedentary controls was conducted. Diets including omega-3 and omega-6 fatty acids were assessed using a validated brief-type self-administered diet history questionnaire. Whole blood lipidomics analysis was performed using the dried blood spot technique before and after a single training session, namely a 2-h shuttle run, and the omega-3 index (EPA + DHA) was calculated. We categorized rugby players based on the proposed omega-3 index risk zones for cardiovascular disease as follows: high risk, <4%; intermediate risk, 4%–8%; low risk, >8%.

Results

The rugby group (n = 29) had a significantly higher intake of omega-3 and omega-6 fatty acids than the control group (n = 31). The blood omega-6 relative concentration did not differ between the groups; however, the rugby group had lower omega-3 fatty acid levels than the control group (4.4 ± 1.1 vs 6.2 ± 1.8%). Approximately 48% of rugby players had an omega-3 index that was considered high risk, and 52% had that considered intermediate risk. None of the patients had a low-risk omega-3 index. A single training session affected the omega-3 and omega-6 metabolic pathways.

Conclusion

Rugby football players may be deficient in omega-3 fatty acids, despite having a higher omega-3 fatty acid intake than controls. The omega-3 index and lipidomics can be used to profile and monitor rugby players. Further nutritional interventions are required to confirm these issues.
A-244 Performance Comparison of the Alinity i Hepatitis C Core Antigen Assay in Routine Laboratory Testing vs HCV RNA Testing
Authors: Gunsolus I L , Prostko J , Pearce S , Degaga B , Eickstead S , Thapa S , Radman C , Taylor R , Grieshaber J , Richard K , Hoffman A , Pekalska A
Published: September 2023

Background

The elimination of Hepatitis C by 2030 is a goal established by the WHO and other country specific health organizations worldwide. This goal is enabled by the availability of effective treatment regimens. A recent surprise in the US has been the increase in HCV infections during the COVID 19 pandemic, which may be caused by increased needle sharing. HCV Antibody assays have been used to screen for HCV, but confirmation of acute infection is relegated in the current US guidelines to PCR which often takes multiple days and may result in a loss to follow up and treatment, especially in high prevalence populations. HCV Core Antigen is a new immunoassay on the Alinity i system. The aim of the study was to evaluate the precision, linearity, and sensitivity of this research use assay in a US-based population.

Methods

Alinity i assay HCV Ab is an automated chemiluminescent immunoassay built to measure total antibody to the virus. Similarly, the Alinity i HCV Core Ag is a research use only automated chemiluminescent immunoassay for detection of HCV Core antigen in human plasma and serum. Precision (repeatability, and reproducibility) was determined over 3 days (4–10 replicates/day) using control material consisting of a negative human plasma control, and positive controls made with recombinant core Ag in buffer. Linearity was evaluated by preparing 4 dilutions of a remnant specimen with detectable HCV RNA viral load. Clinical sensitivity was determined using 90 remnant specimens with positive HCV Ab results. Specimens were confirmed positive for Hepatitis C via HCV RNA quantitation using the Aptima HCV Quant Dx transcription-mediated amplification (TMA) assay on the Panther System. Correlation between the HCV Ag assay and TMA was evaluated using specimens submitted for either Hepatitis C infection screening and monitoring of known infection.

Results

The repeatability of the HCV Ag assay ranged between 3.7% and 11.1% CV depending on the sample S/CO level tested. Dilution recovery averaged 98.2% (range 90.2%–107.3%) and a plot of HCV Ag concentration vs dilution factor showed a correlation coefficient R = 0.998 The Hepatitis C core antigen assay had a correlation coefficient R = 0.92 with the TMA. The HCV assay demonstrated a clinical sensitivity of 96.7% vs TMA.

Conclusion

The performance characteristics of the Alinity i HCV Core Ag assay highlight an opportunity to speed time to treatment by reflexing on the same instrument from HCV Ab to Ag and confirming effectiveness of treatment.
A-273 Multicenter Assessment of the Accuracy of MIC Results for Piperacillin/Tazobactam with MicroScan Dried Gram-Negative MIC Panels using CLSI Breakpoints
Authors: Chipman A , Omai G , Harrington A , Traczewski M , DesJarlais S , Beasley D , Diaz J , Brookman R , Hastey C , Chau J
Published: September 2023

Background

MIC data from MicroScan Dried Gram-negative MIC (MSDGN) Panels with piperacillin/tazobactam were evaluated with CLSI-M100-ED32 breakpoints for Acinetobacter, Enterobacterales, Other-Non-Enterobacterales, and proposed CLSI breakpoints for Pseudomonas aeruginosa from a multicenter clinical study. MIC results were compared to results obtained with CLSI frozen broth microdilution panels.

Materials/Methods

The study included a total of 683 clinical isolates tested using Prompt and turbidity during efficacy and challenge phases. MSDGN panels were evaluated at three clinical sites, comparing MIC values obtained using MSDGN panels to MICs utilizing CLSI reference panel. MSDGN panels were incubated at 35 ± 1°C and read on WalkAway System, autoSCAN-4 instrument, and read visually at 16–20 h. Frozen reference panels were prepared according to CLSI methodology, incubated for 16–20 h for Enterobacterales, Other Non-Enterobacterales, and Pseudomonas aeruginosa and for 20–24 h for Acinetobacter and read visually. CLSI breakpoints(mg/L) used for interpretation of MIC results were: ≤16/4 S, 32/4–64/4 I, ≥128/4 R for Acinetobacter and Other Non Enterobacterales, ≤8/4 S, 16/4 SDD, ≥32/4 R for Enterobacterales, and ≤16/4 S, 32/4 I, >64/4 R for Pseudomonas aeruginosa.

Results

When compared to frozen reference panel results, essential and categorical agreements for all isolates tested are as follows with these recommendations: Due to elevated major error rates for S. marcescens and WalkAway reads with Prompt, results should be confirmed visually prior to reporting. Due to performance with P. rettgeri and S. liquefaciens complex, do not report drug, therapy, or MIC.

Conclusion

Piperacillin/tazobactam MIC results for gram-negative clinical isolates obtained with the MSDGN panel correlate with MICs obtained using frozen reference panels with updated CLSI interpretive criteria.
A-290 Evaluation of a Commercial Turbidity Monitoring System Followed by Mass Spectrometry to Rapid Identification of Microorganisms from Urine Samples
Authors: Nurmberger J M , Inoue F M , Lobo A T , Ramadan D R , Tufik S
Published: September 2023

Background

Urinary tract infections (UTIs) are one of the most common bacterial infections in worldwide and represent a worried public health problem, especially due to a significant rise in global antibiotic use in recent years. The purpose of the study was to evaluate the performance of Uro-Quick (UQ) system (Alifax) and the Vitek-MS system (bioMérieux) to identify bacteria isolates directly from urine samples.

Methods

We analyzed 352 clinical samples of urine. From automated screening by UQ system was used 500 µL of homogenized urine sample manually pipetted into a UQ vial containing 4 mL of broth. The inoculated vials were manually introduced into the Uro-Quick reading unit and incubated for 3 h. The signals are processed by software which monitors the growth curves and calculates the microbial count as colony forming units (CFU/mL). Sample preparation to the mass spectrometry (Vitek-MS) was performed using an in-house protocol based on a centrifugation-wash (CW) method. In parallel with the Vitek-MS direct identification, all the urine samples were submitted to standard culture (SC) method on ChromID™CPS® plate by semi-quantitative technique using 1 µL disposable loop, incubated at 35–37°C and the colony counting were read after 24 and 48h of incubation. Bacterial isolates from positive cultures were identified by Vitek®2 System, according to the manufacture’s recommendations. Cultures with the presence of three or more microorganisms were considered negative.

Results

Out of 334 clinical samples, 261 (78.1%) were negative for the growth by UQ system and for the presence of microorganisms by SC, 78 (21.9%) samples were positive with growth as ≥104 CFU/mL by UQ system, of which 32 samples were also positive with microorganism isolated by SC. Among the 78 microorganisms detected on the samples with growth curve by UQ system, 74 (94.8%) were identified to the species level by the mass spectrometry and 4 (5.2%) were not identified. The microorganisms were Escherichia coli (n = 40), Enterococcus faecalis (n = 12), Klebsiella pneumoniae (n = 6), Proteus mirabilis (n = 4), Citrobacter koseri (n = 4), Streptococcus agalactiae (n = 3), Morganella morganii (n = 2), Enterobacter cloacae (n = 1), Citrobacter freundii (n = 1) and Gardnerella vaginalis (n = 1). Among the 32 microorganisms detected by SC, 28 showed the same identification at species level when was compared with direct identification by Vitek-MS.

Conclusion

This study showed that both UQ and CW methods by Vitek-MS technology used together were able to provides a rapid result (<4 h) for bacterial identification directly from urine samples, that can be useful in clinical practices, especially in severe infectious cases like pyelonephritis. So, future studies should address with a larger number of samples to improve the sensibility of this test for different groups of microorganisms.
A-334 Investigation on Use of NHANES Data to Develop Continuous Pediatric Reference Intervals - Pilot Study with Hemoglobin
Authors: Lyle A N , Akinbami L J , Chen T , Pokuah F , Kit B K , Vesper H W
Published: September 2023

Background

Accurate Pediatric Reference Intervals (PRIs) are critical for assessing health, diagnosing disease, and establishing treatment efficacy. A recent literature review established that current PRIs are inconsistent, and partitioning reference intervals into arbitrary age groups may conceal the underlying biochemistry of child development. To overcome these challenges, continuous PRIs derived using specimens collected with standardized procedures from a well-defined population were proposed. The National Health and Nutrition Examination Survey (NHANES) meets these criteria and could be used to provide accurate PRIs for public health and clinical community use. However, no U.S. studies have described developing continuous PRIs for biomarkers. This study investigates a potential approach to develop continuous hemoglobin PRIs with NHANES data.

Methods

Total hemoglobin values for children and adolescents 1–19 years from NHANES 2011–2018 were assessed. To exclude potentially abnormal hemoglobin values, individuals with diabetes, anemia, BMI >95th percentile, serum cotinine >10 ng/L, C-reactive protein >10 mg/dL, and self-reported tobacco use, or poor health were excluded. Hemoglobin values at the 5th, 50th, and 95th percentiles were estimated at 6-month increments of age for males and females using survey weights. Continuous curves over the age range were then generated using smoothing methods.

Results

The initial sample size was 16 315, of which 3 183 had missing hemoglobin values. After applying exclusions (n = 3 311), the final sample size was 9 821, of which 51.8% were males and 48.2% were females. Males had higher hemoglobin levels with a steeper slope in the curve over the age range and an increase in slope with adolescence, whereas hemoglobin levels in females peaked around age 12 before plateauing.

Conclusion

This investigation suggests that cross-sectional NHANES data can be used to develop continuous hemoglobin PRIs that reflect the physiologic changes commonly obscured by age group binning. More detailed assessments of appropriate sample exclusions and smoothing methods are underway.
A-370 High Rates of Potassium, Chloride and Hemoglobin Discordances in Split Samples Drawn within 1 minute and Analyzed on Point of Care GEM 5000 and Central Laboratory Roche Cobas 8000 and Sysmex Analyzers
Authors: Cembrowski G , Xu Q , Sadrzadeh H
Published: September 2023

Background

Previously, we used serial intensive care unit patient data as well as split sample glucose comparisons to characterize the analytical performance of the GEM 4000 and its tendency to generate outliers in the early to late evening. In this work, we summarize the discordance rate of 2 years of split specimens (minimally 17 700 patient care samples) that were drawn within 1 minute of each other and analyzed on the GEM 5000, Roche Cobas 8000 and Sysmex analyzers.

Methods

Two years (2020 and 2021) of GEM-central laboratory Cobas 8000 and Sysmex comparisons were obtained for potassium, sodium, chloride, glucose and hemoglobin (Sysmex). We used the GEM's iQM2 control (drift) limits to define discordant differences between the GEM and Roche/Sysmex analyses. We graphed the differences vs time of day and applied Dahlberg's formula to derive the magnitude of the running variation of the differences.

Results

The Table summarizes the drift limits, the number of comparisons performed over the two-year period and the average incidence of discordances over the 24 hour period. What strikes the casual observer is the asymmetric distribution of the discordances. More subtle is the lower frequency of potassium and hemoglobin discordances in the early morning and the higher frequency in the late afternoon and evening. The Dahlberg running variation graphs readily demonstrate this diurnal pattern.

Conclusion

The GEM 5000 overcalls increases in potassium, decreases in chloride and increases in hemoglobin. We recommend that other laboratories verify these findings.
A-388 Evaluation of Performance of the nBili Assay on the RAPIDPoint®500e Analyzer Compared to the Total Bilirubin Assay for the Dimension EXL200 and Atellica CH Analyzers in Neonates Blood Samples
Authors: Paula R F , Lamo T C , Lage M S , Midrigal A D
Published: September 2023

Background

Neonatal hyperbilirubinemia is very common, with 60% of term newborns (NB) and 80% of premature neonates developing this condition. If not diagnosed and treated, can lead to severe complications, with bilirubin encephalopathy (BAE) being one of the most feared outcomes. Analysis of whole blood samples measured by the RapidPoint®500 Blood Gas Analyzer (RP500) is a technology option that provides rapid bilirubin results with a small sample volume and can also measure other important analytes. However, it is still unclear whether the blood gas analyzer can be used for biochemical dosage of bilirubin in newborns.

Objective

This study aimed to evaluate the clinical and analytical reliability of the method for detecting bilirubin in infants in comparison with classic biochemical analyzers such as Atellica® CH 930 and Dimension® EXL200.

Methods

A comparative clinical study was performed to evaluate the acceptable analytical agreement of total bilirubin results from 41 samples from neonatal patients between Atellica® CH 930, Dimension® EXL200 and RapidPoint®500 analyzers. Data were analyzed using Vericheck® software.

Results

Forty-one whole blood samples from newborn patients were analyzed for total bilirubin measurement. The range of analyzed results was from 2.7 to 20.8 mg/dL. Were considered for the analysis of clinical data: gestational age, weight, age, visual assessment of the newborn, criteria for hospitalization, whether phototherapy was performed and how long it took. In the regression analysis, it was possible to obtain a Pearson regression coefficient of 0.9806 between the Atellica® CH 930 and RP500 analyzer. The average of the values obtained with the RP500 was 10.8 and for the Atellica® CH930 it was 11.10, obtaining a percentage difference of means of 2.70%. In comparison with the Dimension®EXL200 analyzer, it was possible to obtain a Pearson correlation coefficient of 0.9814. The average of the values obtained with the RP500 was 10.8 and for the Dimension it was 9.32, resulting in a percentage difference of mean of 15.83%.

Conclusion

The study showed good results for analytical comparability between analyzers. There was no change in the clinical management according to the criteria analyzed in conjunction with the laboratory analyses, making it possible to guarantee the safety of using the RP500 platform in the diagnosis and follow-up of newborns with suspected hyperbilirubinemia.
B-007 Measurement of Cytokines in Bronchoalveolar Lavage (BAL) Fluid and CSF Supports Model Development for Discovery Programs
Authors: Lambert T , Lynch K , Cortina R , Schultz M , Lewandowski T , Sellers T
Published: September 2023

In our laboratory, increased demand for cytokine measurements to support both safety and efficacy endpoints across discovery programs has also resulted in cytokine analyses in biological fluids other than routine serum or plasma samples. Recently we have evaluated cytokines in bronchoalveolar lavage (BAL) fluid and CSF to support a mouse respiratory infection and a rat neuroinflammatory model, respectively. Fit-for-purpose validation of these sample types is necessary to confirm cytokine methods are suitable for use, including selection of optimal sample dilutions to reduce or eliminate any matrix effects or interferences. Meso Scale Discovery® (MSD Gaithersburg, MD) methodology was used for measuring cytokines and validation parameters included precision and accuracy of calibration curves (CV% and %Relative Error <20%) to confirm LLOQ and ULOQ for each cytokine method, precision of results for quality control and study samples (CV ≤ 20%) and linearity of response in samples. In development of the mouse respiratory infection model, cytokines IL-1β, IL-6, KC/GRO and MCP-1 were increased in BAL fluid (up to 2892-fold) 20 h post-infection compared to sham and vehicle control groups. Once the model was established, treatment of mice with Compound A demonstrated statistical decreases in these cytokines in BAL fluid compared to an infected control group. Dilutional linearity demonstrated that a minimal required dilution of 1:2 was required for mouse BAL fluids. In support of development of the rat neuroinflammatory model, cytokines IL-1β, IL-6, KC/GRO, MCP-1 and TNF-α were increased (325X, 13X, 28X, 23X and 7.7X, respectively) in CSF compared to plasma at 24 h post treatment. Dilutional linearity evaluations demonstrated that CSF samples can be run neat but a 1:4 dilution was required for plasma samples. In conclusion, fit-for-purpose validation confirmed MSD methods were acceptable for use in supporting these drug discovery models.
B-010 Comparison of Manual Urine Dipstick and Microscopy With Automated UC-3500 and UF-4000 Sysmex UN Series Urinalysis; A Comparative Experimental Research Approach at an Urban Referral Hospital in Ghana
Authors: Toboh E , Ephraim R K , Osei Darkwah K , Afriyie Gyamfi N , Duah Agyemang L , Kumah Forkuo E , Antwi P , Appiagyei K
Published: September 2023

Background

Urine analysis is one of the most common tests for assessing urinary-tract and kidney diseases. In recent years several automated instruments examining urine have been introduced. Though the introduction of automated urine analyzers is expected to reduce the labour involved, turnaround time and potential assay variations, manual urine analysis remains the gold standard or reference method for the analysis of urine. The new Sysmex UN-Series is believed to offer superior performance than other automated systems and manual methods.

Methodology

A total of 67 routine freshly voided midstream urine samples were analyzed within 1 hour in our study. The results of the automated system were compared with the results of the manual processing which consisted of physical, dipstick chemistry and sediment analysis. Correlation and concordance/agreement between the automated and the manual system were assessed by Bland-Altman plot and Cohen’s Kappa analysis respectively.

Results

There was a significant fair agreement between the manual analysis and Sysmex UF-3500, in the determination of urine physicochemical parameters (k = 0.193, P = 0.004). Both showed a significant moderate correlation (r = 0.593, P < 0.001) and a significant fair agreement (κ = 0.109, P < 0.001) for specific gravity and pH determination respectively. The best concordance between the two methods was in the nitrates (κ = 1.000, P < 0.001). Both systems recorded strong positive correlation for RBC (r = 0.951 and R2 = 0.904) and WBC (r = 0.91 and R2 = 0.822, P < 0.001) counts. Together, they had a significant good agreement [(65/67(97.0%), κ = 0.734, P < 0.001)] and a significant fair agreement [(48/67 (71.6%) κ = 0.065, P = 0.491)] for cast and bacteria counts correspondingly.

Conclusion

We conclude that the new automated Sysmex-UN series urine analyzer can be safely used in our laboratory since it demonstrated good performance and compatibility with the manual method. We recommend that microscopy results of the automated platform should be confirmed by manual microscopy, particularly in pathological samples.
B-023 Optimizing Measurement of Homocysteine in an Emergency Care Pathway
Authors: Grzych G , Marchand D , Clarence D , Emeline G , Schult R , Van Nieuwenhuyse E , zerimech F
Published: September 2023

Background/Context

New indications for homocysteine measurement have emerged in recent years, and homocysteine is now being used as a marker of nutritional deficiency as well as a marker of nitrous oxide intoxication and there is a need to return quickly results to adapt the treatment and orientate diagnosis. Current rapid methods are not adapted to extremely high values encountered which are frequently greater than 50 µmol/L that need use of mass spectrometry that is unfortunately not adapt to emergency. Hence, we evaluated here a new immunological method that allows for the reliable and rapid rendering of homocysteine results in order to integrate it into our care pathways.

Method

We prospectively measured plasma homocysteine using both liquid chromatography-mass spectrometry (UPCL—Sciex AP 3200) and the Chemiluminescence Immunoassay (CLIA) method (Maglumi-Snibe). To limit the bias for each assay, the analyses were performed on the same EDTA plasma sample with the same pre-analytical treatment. Bland-Altman plots and Deming regression were used to assess agreement between the homocysteine LC-MS/MS method and homocysteine CLIA method.

Results

Our study included 169 paired samples. The intra- and inter-assay imprecision was comprised between 0.73–2.21% and between 2.75–3.73%, respectively. Linearity, without sample dilution, was acceptable in the range of 5–70 mol/L. This CLIA assay correlated with the HCY LC-MS/MS assay with a slope of 0.9334, intercept of 1.750, R2 = 0.9637 and average bias of −0.6867 μmol/L.

Discussion

The CLIA method produces results comparable to mass spectrometry while significantly reducing analysis time and result delay. This method is thus more appropriate when homocysteine is used not only for emergency diagnosis but also for nutritional monitoring of the patient. This method also allows for the measurement of extremely high concentrations, which are becoming more common in laboratories.
B-044 Analytical validation of an serum glycerol measured by nuclear magnetic resonance spectroscopy NMR
Authors: Wang Q , Scott R , Meeusen J , Donato L
Published: September 2023

Background

Glycerol kinase deficiency (GKD) is a rare X-linked recessive disorder biochemically characterized by hyperglycerolaemia. Adults with GKD are usually asymptomatic. However, they often present with pseudohypertriglyceridemia because most clinical triglyceride methods measure enzymatically generated glycerol from triglycerides. Currently, assays for measuring plasma glycerol are lacking. We describe a preliminary validation of glycerol measured by nuclear magnetic resonance spectroscopy (NMR).

Methods

Serum glycerol was measured by NMR (Numares AG, Regensberg, Germany) using a Ascend 600 NMR (Bruker, Billerica, MA). Stability and matrix effects were determined by repeat measurement of 10 freshly collected samples following various storage conditions. Normal donors were recruited for reference interval (n = 143). Analytical specificity was assessed by spiking red cell lysate, bilirubin and intralipid. Precision was assessed by measuring three pools five times for five days. Accuracy was performed by spiking known concentrations of glycerol. Accuracy was assessed using an enzymatic method (Randox Laboratories, Ltd. County Antrim, UK) on a Roche Cobas c501 (Roche Diagnostics, Indianapolis, IN) as reference.

Results

Measured glycerol increased over time in both serum and plasma, however, prepared samples were stable on the instrument for up to 24 hours. Measured glycerol was not impacted by hemoglobin (1000 mg/dL) or bilirubin (625 mg/dL), however, spiking Intralipid® prevented any measurement. NMR and enzymatic assays strongly correlated, with a constant bias (Table 1). Repeatability and reproducibility were <10% CV and % recovery from glycerol standard were >80% for all concentrations.

Conclusion

Pre-analytical stability, imprecision and accuracy were acceptable for clinical measurement of glycerol using NMR. While there is a significant systematic bias with enzymatic methods, further studies in normal and disease populations will be necessary to determine clinical impact.
B-048 Performance Evaluation of the New Anti-Streptolysin-O Assay on Mindray BS-2800M System
Authors: Chen W , Liu S , Jiang M , Wang J , Dai J
Published: September 2023

Background

Elevated serum concentrations of Anti- Streptolysin-O(ASO) can be used to provide serologic evidence of past or present infection by β-Hemolytic Streptococci. Increasing serum concentrations of ASO antibodies are produced in response to ASO exotoxins secreted by the bacteria. Measurement of ASO antibody levels in serum can be used as an aid in the diagnosis of diseases such as glomerulonephritis, rheumatic fever, bacterial endocarditis, tonsillitis, and scarlet fever, etc. The New ASO assay has been evaluated on Mindray BS-2800M that is an automated, high throughput, and low cross-contamination system. The evaluation of this assay included precision, linearity, dilution accuracy, interference, high dose hook, and method comparison studies.

Methods

The new ASO reagent contains R1 buffer and R2 with latex particles conjugated with in-house made ASO antigen. The R1 is incubated with human serum sample containing ASO antibodies for 5 min at 37°C and then R2 is added. After another 5 min of incubation, immune-aggregation complex is formed. The increased turbidity is measured at 570 nm. By constructing a six-level calibration curve (water is used as reagent blank) from the absorbances of calibrators, the ASO antibody concentration of the sample is determined.

Results

The precision study was run according to EP05A3 with two commercial controls (approximately 80 and 300 IU/mL) and two serum sample pools (approximately 150 and 400 IU/mL) on the Mindray BS-2800M system. The repeatability and within-lab CVs ranged from 0.8% to 2.0% and 2.0% to 6.0%, respectively. The analytical linearity of the assay was determined as from 20 IU/mL to 1000 IU/mL with the limit of blank of 2 IU/mL and limit of detection of 10 IU/mL. The dilution accuracy was evaluated by diluting high ASO level samples at upper region of assay range using saline with 5-fold and run neat and diluted samples. The deviation in recoveries between diluted sample after calculation and the neat sample was found to be less than ±10%. The new ASO assay showed <±10% interference with bilirubin (conjugated or free) up to 40 mg/dL,hemolysate hemoglobin up to 1000 mg/dL,Intralipid up to 1000 mg/dL,and Triglycerides up to1000 mg/dL. The assay on the Mindray BS-2800M system(y) correlated well with the ASO assay(x) on the Beckman AU5800 system:y = 1.01 x + 1.55(r = 0.9514,n = 95,range:50–971 IU/mL). No prozone was observed with the assay on the Mindray BS-2800M system up to the highest ASO antibody concentration of 5000 IU/mL.

Conclusion

We conclude that the New ASO assay with in-house developed ASO antigen raw material, when used on the Mindray BS-2800M system, can measure serum ASO antibody concentrations precisely and accurately over a broad range. It is suitable for use in routine clinical laboratories.
B-052 Establishment of New Antibodies and ELISA System to Detect the Potato Alkaloids α-Solanine and α-Chaconine
Authors: Okada K , Matsuo K
Published: September 2023

Background

Food poisoning by potato alkaloids, α-solanine (SO) and α-chaconine (CHA), currently occurs worldwide, however laboratory methods have not yet been established to detect these toxins in biological samples. In this study, we established new antibodies to detect SO and CHA and evaluated the practicality of enzyme-linked immunosorbent assays (ELISAs) using these antibodies in laboratory medicine.

Methods

Solanidine, a chemical compound found in both SO and CHA, was conjugated with bovine albumin, and this complex was repeatedly injected into two rabbits for two months. Two types of polyclonal solanidine antibodies were then purified from rabbit serum using affinity column chromatography. Using these antibodies, two forms of direct ELISAs (Sold ELISA-1, 2) were constructed. The basic detection performance of the ELISAs was confirmed by measuring the levels of SO and CHA diluted in phosphate-buffered saline (PBS). To simulate biological samples from patients with potato food poisoning, SO and CHA powders were mixed with commercially available human serum and urine, and SO and CHA levels were then measured using ELISA. Lastly, SO and CHA levels were detected in extracts from rotten potato (Irish Cobbler) sprouts, peels, and tubers.

Results

In samples of SO diluted in PBS, the limit of quantification (LoQ) was determined as 2.56 ng/mL and 9.55 ng/mL for Sold ELISA-1 and -2, respectively. In CHA diluted in PBS, the LoQs of Sold ELISA-1 and -2 were 1.36 ng/mL and 4.8 ng/mL, respectively. The LoQs of SO in the serum were calculated as 14.25 ng/mL and 19.41 ng/mL using Sold ELISA-1 and -2, respectively. In contrast, the LoQs of CHA in the serum were 12.48 ng/mL and 16.92 ng/mL using Sold ELISA-1 and -2, respectively. The LoQs of SO in the urine were determined as 30.28 ng/mL and 45.16 ng/mL using Sold ELISA-1 and -2, respectively. Conversely, the LoQs of CHA in the urine were 22.92 ng/mL and 38.15 ng/mL using Sold ELISA-1 and -2, respectively. Using Sold ELISA-1, both SO and CHA in the extracts from rotten potato tubers and peels were detected as approximately 1.7- and 2.3-fold higher, respectively, in each part than those in the extracts from fresh potatoes. When both SO and CHA were measured in the same samples using Sold ELISA-2, the levels were approximately 1.6- and 2.4-fold higher, respectively, in the tubers and peels than those in fresh potato samples. Furthermore, the potato sprout extract contained approximately 80-fold more SO and CHA than the tuber and 8-fold more than the peel.

Discussion and Conclusion

Based on our results, Sold ELISA-1 presented greater performance in detecting SO and CHA than Sold ELISA-2. The non-specific reactions in the serum samples and influence of urea in the urine samples may underlie the reduced detection performance of SO and CHA in ELISA, respectively. Although the sensitivity depends on the sample type, these ELISAs may be effective as future clinical and food testing methods.