bluuebunny/crossref_metadata_2025 huggingface dataset:
A-124 Evaluation of the Analytical Performance of 10 General Chemistry Assays on the Atellica® CI 1900 Analyzer
Authors: Kolewe K , Micklitsch C , Ostolaza-Venegas K , Pham T , Tyler C , Varhue W , 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 employing both Atellica chemistry and Atellica immuno assays. This study was designed to evaluate the analytical performance of the Atellica CH Alkaline Phosphatase concentrated (ALP_2c), Direct Bilirubin 2 (DBil_2), Total Bilirubin_2 (TBil_2), Albumin (Alb), Albumin BCP (AlbP), Total Protein II (TP), Aspartate Aminotransferase (AST), Aspartate Aminotransferase P5P (ASTPLc), Alanine Aminotransferase (ALT), and Alanine Aminotransferase P5P (ALTPLc) assays* on the Atellica CI 1900 Analyzer.

Methods

The Atellica CI 1900 ALP_2c, DBil_2, TBil_2, Alb, AlbP, TP, AST, ASTPLc, ALT, and ALTPLc assays use the same reagents and calibrators as the Atellica Chemistry 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 serum 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 serum samples were analyzed using the Atellica CH assays on both the Atellica® CH 930 and Atellica CI 1900 Analyzers.

Results

Representative precision and MC results are listed for each assay in the table below. For the nine assays tested, repeatability and within-lab %CVs were <6.0% and <9.0%, respectively. Slopes determined by the Deming linear regression model were approximately equal to 1.

Conclusion

Evaluation of the Atellica CH ALP_2c, DBil_2, TBil_2, Alb, AlbP, TP, AST, ASTPLc, ALT, and ALTPLc assays using the Atellica CI 1900 Analyzer demonstrated acceptable precision and equivalent performance compared to the same assays on the Atellica CH 930 Analyzer.

*The products mentioned are not commercially available in all countries. Their future availability cannot be guaranteed.
A-126 Evaluation of NMR-based GFR Estimation in Dosing of High-dose Methotrexate
Authors: Schwäble Santamaría A N , Einhell S , Robertson A N , Grassi M , Pukrop T , Schiffer E
Published: September 2023

Background

The cytotoxic agent methotrexate (MTX) is mainly used in oncology and rheumatology. MTX is 80%–90% excreted unchanged in the urine, thus, impaired renal excretion because of kidney disease leads to accumulation and prolonged exposure, with a consequent increased risk of myelosuppressive and other toxic adverse effects. Direct kidney damage from MTX crystal precipitation and tubular injury may also occur. Therefore, precise and accurate measurement of renal function prior to MTX administration is of paramount importance to determine accurate dosing and to minimize such adverse risks. Commonly used estimated glomerular filtration rate (eGFR) equations perform poorly in patients with cachexia and at later stages of life—the typical oncology patient. Here we evaluate the feasibility of applying the recently introduced nuclear magnetic resonance (NMR)-based GFR equation (GFRNMR) using creatinine, cystatin C, myo-inositol, and valine, in oncology patients receiving high-dose MTX.

Methods

A series of residual sera from patients scheduled to receive high-dose MTX infusion for oncological indications were collected from two sites: n = 52 sera from the University Hospital Regensburg (Regensburg, Germany), at four time points (t0h, t24h, t42h, and t48h), and n = 10 cross-sectionally from the Mayo Clinic (MN). Standard drug-monitoring trough levels were used as a reference. Serum was prepared and NMR-measured in five replicates for all samples. GFRNMR was compared with the current standard GFR equations: i) CKD-EPI2021Cr (creatinine) and ii) CKD-EPI2021CrCys (creatinine and cystatin-C). Coefficient of determination for linear regression, kappa coefficient for categorical regression and bootstrapped confidence intervals were calculated.

Results

MTX was shown not to increase the GFRNMR failure rate or affect the intra-assay precision of GFRNMR. When monitoring eGFR during high-dose MTX treatment, MTX affected GFR according to the RIFLE criteria for AKI in 13 cycles in 9 patients; 1/13 were classified as ‘risk’ (creatinine increased 1.5-fold) and 1/13 were classified as ‘injury’ (creatinine increased 2.0-fold). Using MTX clearance as a surrogate for measured GFR, GFRNMR was shown to reflect the MTX plasma clearance constant k more accurately (using a fitting function c = c0*e−kt) with r = 0.758 (95% CI 0.36–0.92, P = 0.004) compared to CKD-EPI2021Cr (r = 0.401, 95%CI −0.19–0.78, P = 0.176) and CKD-EPI2021CrCyc (r = 0.632, 95% CI 0.12–0.88).

Conclusion

The robustness of GFRNMR test results is not affected by HD-MTX treatment. Compared to standard eGFR equations, GFRNMR is more closely associated with MTX renal clearance rates and may therefore be a novel method to improve the accuracy of MTX dosing in the future.
A-137 Performance Evaluation of an Automatic, Rapid and Non-Westergren Based Method for Erythrocyte Sedimentation Rate Measurement
Authors: Hsiang-Ling H , Fang-Yu W , Hao-Ru L
Published: September 2023

The erythrocyte sedimentation rate (ESR) is widely used for the assessment of acute or chronic inflammation, especially for rheumatoid diseases. The gold standard for determining ESR is the Westergren method, which measures the distance in millimeters that red blood cells fall in one hour. However, this method needs to be performed manually, which increases the biohazard risk to laboratory personnel, and the results are often influenced by many preanalytical and analytical factors. Several automated ESR analyzers with different methodologies are now available to provide faster results directly from whole blood anticoagulated with K3EDTA. In this study, we evaluated the performance of an automatic ESR analyzer, Alifax TEST1, and compared it with that of another automatic analyzer, Diesse Cube 30 touch, and also the Westergren method. TEST1 extrapolates the ESR values by measuring the kinetics of red cells aggregation in 20 s, while Cube 30 is a modified Westergren method that could obtain the results in 20 min. A total of 75 clinical samples were analyzed for ESR using the three methods. The hematocrit (Hct) and C-reactive protein (CRP) values were also analyzed. The Spearman correlation coefficient between TEST1 and Westergren methods was 0.90 (P < 0.0001) with a mean difference of -5.45; the correlation between Cube 30 and Westergren methods was 0.80 (P < 0.0001) with a mean difference of 10.74; the correlation between TEST1 and Cube 30 was 0.69 (P < 0.0001) with a mean difference of -15.9. The precision values (CV %) of TEST1 in low-, medium- and high-level controls were 2.71%, 1.21% and 1.05% for inter-assay, and 3.70%, 1.66% and 0.86% for intra-assay. The normal range of TEST1 was also established by analyzing ESR values of 125 healthy individuals where it is 0–15 mm/hr for men ≤50years old, 0–20 mm/hr for men > 50 years old and for women ≤50 years old, and 0–30 mm/hr for women > 50years old. The ESR values obtained from the three methods all significantly correlated with plasma CRP levels. However, the ESR values from Cube 30 and Westergren methods negatively correlated with Hct values, while that from TEST1 did not. The present study demonstrates that 1) TEST1 has a better correlation and a lower difference to the Westergren method compared to Cube 30, suggesting that TEST1, the automatic, rapid and non-Westergren based method is an effective assay for clinical practice; 2) the Westergren based methods are more easily influenced by Hct; 3) the large mean difference between TEST1 and Cube 30 highlights a need for harmonization of the ESR values obtained from different automatic analyzers, especially when it is applied to monitor the disease activity score (DAS28) in rheumatoid arthritis patients.
A-139 Investigating the Utility of Reticulocyte Hemoglobin Equivalent for Diagnosis of Iron Deficiency Anemia
Authors: Lee H , Wang F , Ho H
Published: September 2023

Background

Iron deficiency anemia (IDA) is one of the most common leading global health problems, which could cause extreme fatigue, chest pain, headache, and even neurodevelopment deterioration in children. Traditionally, assessing serum ferritin, transferrin, and iron are the tools to diagnose IDA. However, a high false-positive rate of these conventional biomarkers might be observed due to inflammation, infection, or malignancy. Reticulocyte hemoglobin equivalent (RET-He) is a new parameter that reflects the recent functional availability of iron for erythropoiesis, with the advantage of real-time results as part of automated reticulocyte analysis. The present study, therefore, aimed to investigate the utility of RET-He for the diagnosis of patients with IDA.

Methods

This retrospective study collected laboratory data from patients with both serum ferritin and reticulocyte results from January 2022 through December 2022, and excluded the high white blood cell count (WBC > 9380 cells/μL) and high C-reaction protein (CRP > 0.5 mg/dL). RET-He was measured by Sysmex XN-10 or XN-20 automated hematology analyzer (Sysmex, Kobe, Japan). Serum ferritin was measured by Roche Cobas e801 (Roche Diagnostics, Mannheim, Germany). Iron and total iron binding capacity (TIBC) were measured by Roche Cobas c702 (Roche Diagnostics, Mannheim, Germany). Anemia was defined as hemoglobin concentration <13 g/dL for men and < 12 g/dL for women. Iron deficiency was defined as serum ferritin <15 μg/L. Student T-tests and Pearson correlation were performed, and P-values less than 0.05 were considered statistically significant. Statistical analyses were performed with SPSS software (Version 22.0).

Results

A total of 2208 patient data were enrolled in this study and were classified into the IDA, iron deficiency, anemia, and control groups according to ferritin level and hemoglobin concentration. The RET-He were 20.6, 27.7, 30.4, and 32.3 pg in the IDA, iron deficiency, anemia, and control groups, respectively. The IDA group showed significantly lower RET-He levels than the control group (P < 0.001). By Pearson correlation analysis, the RET-He showed a weak positive correlation with ferritin and hemoglobin (r = 0.236, 0.274), moderate positive correlation with iron (r = 0.354), and moderate negative correlation with TIBC (r = −0.369). In addition, the average turn-around time (received-reported) of RET-He was 16.4 min, which was shorter than other biochemical markers such as ferritin, iron, and TIBC (57.7, 34.2, 34.4 min).

Conclusion

The RET-He could be an assessment of the iron actually used for the biosynthesis of hemoglobin and as a useful and rapid tool for diagnosing and monitoring iron deficiency anemia.
A-140 Evaluating the Performance of Various Lupus Anticoagulants Tests Among Different Coagulation Platforms
Authors: Wang F , Lee H , Chen Y , Ho H
Published: September 2023

Background

Lupus Anticoagulants (LAs), one of the antiphospholipid antibodies, are risk factors for arterial or venous thrombosis with complications such as stroke, acquired thrombophilia, and pregnancy loss. Detection of LAs is challenging for laboratories as the heterogeneity of antibodies and epitopes on protein in the phospholipids. Thus, no single test is sensitive for all LAs, and the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee (ISTH) recommended laboratory should provide two test systems based on different principles, which dilute Russell's viper venom time (dRVVT) should be as the major test, and partnered with LA-sensitive activated partial thromboplastin time (aPTT). There are many different mechanisms of tests proposed by various manufacturers, however, the comparison of different platforms by different manufacturers on LAs remains unknown. In this study, we aimed to evaluate the performance of various LA tests among different platforms.

Methods

A total of 76 specimens from September to December 2022 were collected. dRVVT (dRVVTIL) and silica clotting time (SCTIL) were performed by ACL TOP 500 analyzer (Instrumentation Laboratory, US). In addition, ellagic acid-based aPTT (Siemens Dade Actin FSL reagent, aPTTAFSL), silica-based aPTT (Siemens Pathromtin SL reagent, aPTTPSL), and dRVVT (dRVVTsysmex) were performed by Sysmex CN-6000 analyzer (Sysmex Corporation, Japan). Analytical performances, agreements, and McNemar's test were calculated.

Results

All 76 specimens were originally tested by dRVVTIL and SCTIL, and showed that 30 specimens were positive for both assays, 6 were only positive for dRVVT, 5 were only positive for SCT, and 35 specimens were negative for both assays. In addition, all samples were further tested by dRVVTsysmex. Compared with the integrated use of dRVVTIL and SCTIL, dRVVTsysmex showed 100.0% (41/41) positive agreement and 91.4% (32/35) negative agreement. 3 specimens could only be tested positive on the dRVVTsysmex platform, of which one patient was diagnosed with systemic lupus erythematosus (SLE), another patient was diagnosed with infertility, and the other patient was diagnosed with antiphospholipid syndrome (APS). To further evaluate the performance of aPTT on LA screening, 44 specimens with either dRVVTIL, SCTIL and dRVVTsysmex positive were considered LA-positive and further tested by different aPTT assays. The positive agreement was 65.9% (29/44; 95% CI: 50.1–79.5%) and 77.3% (34/44; 95% CI: 62.2–88.5%) on aPTTAFSL and aPTTPSL, respectively, however, there was no significant difference between the positive agreement of two assays (P = 0.13).

Conclusion

Compared with the integrated use of dRVVTIL and SCTIL, dRVVTsysmex could achieve the same detection rate on LA. Furthermore, aPTTAFSL and aPTTPSL showed no significant difference between the positive agreements for LA-positive specimens.
A-148 Thromboelastography Utilization in a Community Hospital Setting
Authors: Allen J L , Christian M , Zuretti A , Bluth M H
Published: September 2023

Background

Thromboelastography (TEG) applications have been gaining momentum in various clinical settings and service lines. However, the utilization of the technology varies among clinical establishments and requires additional assessment for TEG optimization among its user groups.

Methods

TEG (Haemonetics TEG6s) was applied in a community hospital based setting in SICU, OR and ED service lines to identify instrument prompted blood product support over a two month time period.

Results

Forty one measurement were obtained from twenty patients. SICU represented the majority of TEG use (78%) followed by OR (15%). Global TEG run assessments were completed on 27%, platelet mapping on 46%, and heparin assessment on 56% of samples. Global TEG recommendations included factor deficiency with suggested FFC or PCC use (12%) or no recommendations (10%). Platelet assessments recommended no product (19.5%), or ADP inhibition with platelet consideration if bleeding (14.6%). Heparin assessment indicated no treatment (44%) and above normal CK/R time with FFP or PCC if bleeding (10%).

Conclusion

TEG applications in various services suggested no need for blood product or factor application in the majority of platelet mapping and heparin assessments. Other assessments yielded about a half dozen suggestions from the instrument’s 150 suggestion options. TEG application appears to be easily implementable and suggests no treatment or a few repetitive treatment options for the majority of patients assessed thereby reducing onboarding educational and improving management requirements for select user groups.
A-158 Evaluation of Nucleated Red Blood Cells NRBC) Count on Mindray BC 6800Plus
Authors: Correa Wengerkievicz Lopes A , Siqueira Castanhel A , Muniz Ribeiro Franzon C , Valim Franzen J
Published: September 2023

Background

The detection of NRBCs in the peripheral blood is a marker of many pathological conditions andhas significant prognostic value. Microscopy is the traditional method for NRBC count, but it’s time consuming and has low precision and efficacy and requires experienced technicians. TheMindray BC-6800 Plus is a hematological analyzer that brings SF Cube technology, whichquantifies NRBCs in the WNB channel. This channel differentiates basophils and NRBCs, andcounts white blood cells. The present study aims to evaluate if the automated method is preciseand comparable to the manual microscopy.

Methods

Blood samples from 40 patients with NRBC flag from the laboratory routine were evaluated bymicroscopy. Blood films were prepared automatically with a Mindray SC-120 slidemaker/stainer.NRBC were manually counted and reported as number of NRBC per 100 white cells, which wasconsidered the reference method. The results of microscopic counts were compared with thoseof the automated method and statistically analyzed using the F-test, T-test and Pearson’ scorrelation coefficient.

Results

The results show good correlation between the methods: F-test of 1.36 (below 1.69); t test (0,2791) below the critical T(2,0210) and Pearson’s correlation coefficient was 0.9, which isconsidered an adequate result. Samples used in this evaluation comprised mainly low results andfew samples with higher counts. The maximum observed value was 41%, which was confirmedby microscopy. It is important that samples with larger counts be evaluated to be sure of thelinearity value of the test.

Conclusion

The results demonstrated that the NRBC counts obtained by Mindray BC-6800 analyzer are inagreement with data from manual counts. However, it is necessary that the accuracy of sampleswith very high counts be investigated and compared with the reference method. Thisimplementation of the automatic release of NRBC can allow the laboratory to reduce the time forreleasing tests and optimize the productivity of microscopists.
A-195 The Application of Six Sigma Metrics to Assess Quality Control of Syphilis Tests in a Clinical Laboratory
Authors: Utiyama A H , Pereira R T , Rodrigues T , Bandeira A C , Ramadan D R , Tufik S
Published: September 2023

Background

Clinical laboratories use quality control processes to monitor and evaluate analytical performance in terms of precision and bias. The periodic measurement of those parameters plays an important role in patient safety and it is a requirement in most accreditation organizations. In recent years, Six Sigma metrics has become one of the most efficient tools to monitor the analytical performance of clinical laboratory systems, since it unifies Total Allowable Error (TEa), random and systematic errors in a single index. However, for many analytes, TEa is not available in the literature based on effect of analytic performance on clinical outcomes or in biological variation. In this case, the TEa must be derived from the “state of art”. In this work, it will be described how Six Sigma was established in our laboratory for Syphilis, with TEa derived from external quality assessment program.

Methods

A year worth of data was gathered from internal quality control and external quality assessment evaluation to assess the imprecision (in terms of coefficient of variation—CV%) and bias for Syphilis tests processes in four modules of Alinity I (Abbott). Data was split into two groups: “Non-reactive” and “Reactive”. TEa was calculated from the external quality assessment for both groups, based on the median CV% of the peer group evaluated in the last 2 years. Six Sigma metrics were calculated from TEa, CV% and bias for each equipment, using the formula Sigma = (TEa-bias)/CV%.

Results

TEa for “Non-Reactive” and “Reactive” levels were estimated at 44,25% and 17,7%, respectively. Six Sigma values calculated for “non-Reactive” level were between 4,6 to 5,38 in every equipment. For “Reactive” level, calculated Six Sigma ranged from 4,24 to 5,82. All values found were classified as Good and Excellent according to the Normalized method decision chart.

Conclusion

Six Sigma is a powerful tool to monitor the analytical performance of the exam. For Syphilis, it is important to monitor “Non-Reactive” and “Reactive” levels separately for a better control over the analytical system. Abbott’s Syphilis test has also a satisfying performance in our laboratory. Also, estimating the TEa from external quality assessment programs is a good alternative for analytes with no quality specifications available in the literature.
A-202 Establishing of Lipid-Apolipoprotein Connectivity Map in Hyperglycemia
Authors: Ivanova A A , Parks B A , Rees J , Kuklenyik Z , Barr J R
Published: September 2023

Background

Hyperglycemia, a condition characterized by a significantly increased glucose level in the blood, can lead to insulin deficiency and pre-diabetes. Lack of insulin production also interferes with lipid metabolism and increases the risk for cardiovascular disease. Thus, diagnosis and treatment of hyperglycemic patients can benefit from advanced proteomics and lipidomics testing approaches.

Methods

Disease-focused serum samples from 50 specimens were collected and evaluated, including 29 specimens with a glucose level>180 mg/dL and 21 normal lipidemic specimens. The sample proteomics analysis was conducted with a Perfinity IDP workstation (Shimadzu Scientific, Columbia, MD, USA) using on-line protein digestion with an immobilized enzyme reactor (IMER) directly coupled to a HALO-C18 column (Advanced Materials Technology, Wilmington, DE, USA). Lipidomics data were collected with the Lipidyzer platform (AB SCIEX, Framingham, MA, USA). Statistical analysis was conducted using JMP software (SAS Institute, USA) and custom scripts.

Results

Using targeted lipidomics and proteomics platforms we identified 20 proteins and 575 lipid species across 10 lipid subclasses. We identified specific lipids and lipoproteins dysregulated in hyperglycemic specimens as compared to the normolipidemic samples and linked them to major metabolic pathways. Lipoprotein particles related-proteins apos A1/B/C2/C3/E and lecithin–cholesterol acyltransferase (LCAT) were significantly dysregulated and associated with changes in HDL-mediated lipid transport, very-low-density lipoprotein particle remodeling, acylglycerol homeostasis, and triglyceride homeostasis.

Conclusion

The conducted integrated analysis of lipid and protein concentrations in hyperglycemia specimens to provide new insights into molecular changes associated with hyperglycemia that may inform new diagnostic and therapeutic strategies. The network analysis can allow improved categorization of patients that can lead to more effective and individualized therapeutic intervention approaches. This study provides new experimental and informatics approaches to better assess underlying metabolic conditions and related diseases, including cardiovascular disease, diabetes, and metabolic syndrome.

Disclaimer

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. Use of trade names is for identification only and does not imply endorsement by the CDC.
A-204 Associations between Apolipoprotein B/A1 Ratio, Lipoprotein(a) and the Risk of Metabolic-associated Fatty liver Diseases in a Korean Population
Authors: Park K , Park Y , Park H , You E , Kim Y
Published: September 2023

Background

Metabolic-associated fatty liver disease (MAFLD) is a new nomenclature of the fatty liver condition associated with metabolic dysfunction. Little study regarding the association between apolipoprotein and lipoprotein(a) and MAFLD has been performed. This study aimed to investigate the association between apolipoprotein B/A1 ratio (apo B/A1), lipoprotein(a), and MAFLD based on new diagnostic criteria in a Korean population.

Methods

This cross-sectional study consisted of 14 420 consecutive adults underwent abdominal ultrasonography among the general Korean population visiting at comprehensive health promotion center in Samsung Changwon Hospital from January 2021 to December 2021. Clinical data, anthropometric and biochemical parameters were reviewed. According to the Asian Pacific Association for the Study of Liver guideline, the MAFLD was diagnosed based on hepatic steatosis by abdominal ultrasonography and the presence of overweight/obesity, type 2 diabetes, or the evidence of metabolic dysregulation. Multivariate logistic regression was conducted to analyze the independent association between apo B/A1 ratio and MAFLD.

Results

The prevalence of MAFLD in the general Korean population was 34.5% (4978/14 420). Multivariate logistic regression analysis revealed that Apo B/A1 ratio (odds ratio: 3.913, P = 0.019) was independently associated with the MAFLD. Lipoprotein(a) levels are inversely associated with the MAFLD, especially in subjects with hepatic fibrosis (P < 0.0001).

Conclusion

Apo B/A1 ratio and lipoprotein(a) have opposite association with the MAFLD in a Korean population. This study suggests that apo B/A1 ratio could be useful biomarkers for MALFD, while lipoprotein(a) should be used with caution as a predictive biomarker for MAFLD.
A-205 Optimized Time Interval for the Measurement of Plasma Lipids for Assessing Cardiovascular Disease Risk
Authors: Sampson M , Cole J , Remaley A T
Published: September 2023

Background

The measurement of plasma lipids are used to predict atherosclerotic cardiovascular disease (ASCVD) risk and for the management of lipid-lowering therapy. The general recommendation is that plasma lipids should be measured at least every 5 years, but the ideal time may vary depending on the baseline risk, which we examined in this study.

Methods

Using lipid values and other risk factors from the National Health and Nutrition Examination Survey (NHANES) (no diabetes, no lipid medications, n = 9704), which is designed to be representative of the US-general population, we calculated a baseline 10-year ASCVD risk with the pooled cohort risk equations (PCE). Future 10-year risk scores were estimated by chronologically increasing age of the subjects and projecting future systolic blood pressure (SBP) and lipid changes, using the mean-percentile age group change in the NHANES population for SBP (no hypertension medications, n = 17 329) and the Lifelines Cohort study for lipids (no CVD or lipid medications, n = 133 540). Crossing high-risk (>20%/10-years; 25% decison limit) and intermediate risk (>7.5%/10-years; 50% decision limit) PCE thresholds were calculated by baseline age to determine the best time intervals for testing lipids.

Results

As shown in the figure, the likelihood of crossing the intermediate or high-risk threshold depends on the baseline risk. Individuals that are close to one of the risk thresholds are more likely to cross it in the subsequent years. Based on this analysis, we recommend the following time intervals for lipid testing: Baseline risk < 5%/10-year: 5-years, baseline risk 5–15%/10-year: 3-years, baseline risk 16–20%/10-year: 1–2 years.

Conclusions

More frequent lipid testing than once every 5 years is desirable, because it would identify at risk patients sooner and allow for earlier therapeutic intervention, which has been shown to increase the effectiveness of statin therapy for reducing ASCVD events.
A-227 First Brazilian External Quality Assessment Program for Monkeypox Molecular Tests: Results from Two Surveys
Authors: Lima S , Barra G , Poloni J A , Barroso J , Lopes R , Mendes M , Montenegro R , Jerônimo D , Brazão F , Biasoli I , Biasoli V
Published: September 2023

Background

The WHO declared the current Monkeypox (Mpox) outbreak a public health emergency of international concern. PCR test is the preferred diagnostic assay. External Quality Assessment Programs (EQAP) provide an independent assessment of the effectiveness of analytical systems, especially with emerging pathogens. There are a few references about EQAP for Mpox. Here, we report the results of the first Mpox EQAP conducted by a Brazilian EQAP provider, which follows the criteria of ABNT NBR ISO/IEC 17043:2011.

Methods

The quality control samples were inactivated lyophilized suspension of Vero cells (BCRJ 0245/ATCC CCL-81) infected with viable Mpox virus particles and cultured under BSL-3 conditions. The EQAP surveys were conducted in September and October/2022. In the first round, two samples were sent—one negative and one positive [cycle threshold (CT) of 23]. In the second round, 5 samples with different viral loads were sent (CT of 24.9/negative/26.5/34.8/34.6). The percentage of correct results (%CR), sensitivity (SE), specificity (SP), false positive (FP), and false negative (FN) were calculated for each sample, and the performance of laboratory-developed test (LDT) or in vitro diagnosis (IVD) was compared.

Results

A total of 49 laboratories (38 from Brazil) submitted 319 datasets with qualitative results. In the first round, 30 laboratories used LDT methods and 11 IVD methods, and in the second round, it was 32 and 14, respectively. The %CR ranged from 81.4%–100%, SE from 83.3%–100%, SP from 95.45%–97.7%, FP from 2.3%–4.55%, and FN from 2.3%–16.3%. Samples with higher FN have lower viral loads (P = 0.00044).The overall % of CR, SE, SP, FP, and FN for LDT methods were 76.7%–100%, 79.3%–100%, 93.3%–100%, 0%–6.7%, and 0%–20%, and for IVD methods were, 90.9%–100%, 90.9%–100%, 90.9%–100%, 0%–3.1%, and 0%–7.7%, respectively. No statistical difference was found between methods regarding these parameters.

Conclusion

This is the first report of EQAP of Mpox molecular testing from Brazil. The EQAP showed that Mpox PCR had an overall good accuracy and performance. FN rates ranged from 2.3% to 16.3%, suggesting there is room for assay improvement, especially with samples with low viral loads. LDT and IVD tests presented similar performance.
A-235 Results and Interpretation: Serology Testing Platforms and Assays Compatibility Assessment for MASTM SARS-CoV-2 IgG Quality Controls
Authors: Wang H , Krishnaswami N , Crandall D , Hu R
Published: September 2023

Background

Serology testing of antibodies against SARS-CoV-2 viruses serves many purposes: disease diagnosis, on-going and surveillance, epidemiologic and vaccine studies, etc. There was a critical need to provide standardized quality control materials for development and harmonization across different test methods and IVD platforms. The MAS™ SARS-CoV-2 IgG Controls are human plasma-based materials containing IgG antibodies against SARS-CoV-2. The control offers commutability by mimicking patient samples and is intended to be used for monitoring serological assays, providing confidence in routine test results, test methods troubleshooting and system errors identification. We report here the compatibility assessment of MAS™ SARS-CoV-2 Controls testing on different assays and platforms.

Methods

The platforms and assays compatibility was assessed for the MAS™ SARS-CoV-2 IgG Positive and Negative Controls across all 11 assays and platforms listed as below. These serology assays target either total antibodies (IgA, IgM, IgG), IgM/IgG, or IgG against either the SARS-CoV-2 nucleocapsid (N), RBD or spike (S) proteins. Replicated samples were tested on each instrument for statistical confidence.

Results

All results demonstrated conclusively the comparable performance of MAS™ SARS-CoV-2 IgG controls across different clinical diagnostic assays and platforms manufactured by Abbott, Roche, Ortho, DiaSorin, Beckman Coulter and bioMérieux. The positive control showed 100% expected reactive results (IgG Positive) and Negative control at 82% non-reactive results, respectively. Furthermore, both controls were compatible towards assays detecting IgG antibodies targeting specific regions (N, S or RBD).

Conclusion

SARS-CoV-2 serology testing remains unstandardized with numerous assays and platforms receiving FDA EUA. While tested on multiple commonly used assays and platforms, MAS™ SARS-CoV-2 IgG Positive and Negative Controls were found to be platform agnostic. To conclude, MAS Controls will contribute to the harmonization of the SARS-CoV-2 Serology assay offerings, monitor the clinical laboratory analytical performance, streamline the workflow on test method development, validation and verification, and routine assessment.
A-251 Comparison of Antimicrobial Susceptibility Profiles of Enterobacteriaceae spp. Isolates from Retail Meat Products Imported from USA and Brazil or Domestically Produced on Caribbean Islands of St. Kitts and Grenada
Authors: Luthra T , Varghese K , Martens A , Fakayode O , Harrington J
Published: September 2023

Background

Enterobacteriaceae species, including Escherichia coli, Klebsiella and Salmonella, are endogenous colonizers of gastrointestinal tract of livestock animals, which pose potential health threats to humans, particularly for individuals with compromised immune systems (Guentzel 1996). The emergence of drug-resistant strains due to the overuse of antibiotics in agricultural practices have increased the urgency to evaluate zoonotic bacteria and to assess potential impact on human and animal health (Llor 2014).

Project Aim and Methods

The aim of this study is to compare the microbial prevalence and antimicrobial resistance profiles of Enterobacteriaceae isolates present on pork and poultry products domestically produced in the Caribbean Islands, St. Kitts and Grenada as compared to poultry imported from USA and Brazil. This study was conducted over a 4-year time period at University of Medicine and Health Sciences (UMHS) in St Kitts and at St. George’s University (SGU), Grenada. Microbial colonies were isolated on MacConkey agar after 24-hour incubation at 36°C in Buffered Peptone Water and identified using standard biochemical assays and API-20E test kit. Antimicrobial susceptibility was evaluated using the Kirby-Bauer disc diffusion on Mueller-Hinton plates.

Results

A total of 44 meat products from Caribbean Islands and 49 meat samples from Brazil and USA were processed to yield 64 and 60 bacterial isolates, respectively. Bacterial colonies isolated from imported meat products displayed higher incidence of antibiotic susceptibility to multiple classes of drugs (MDR = Multiple Drug Resistant) as compared to domestically produced meats. The prevalence of MDR bacteria was 45% MDR isolates from USA-imported chicken as compared to 13% MDR bacteria isolated from chicken domestically raised.

Conclusions

Imported meats exhibit a higher prevalence of antimicrobial resistance, particularly in the beta-lactam class of antibiotics, including amoxicillin and cephalosporins and fluroquinolones. The overuse of subtherapeutic antibiotics in mass scale livestock production is likely creating selective pressure for the overabundance of MDR strains in the gastrointestinal tract of animals. The findings of this study will be communicated to relevant community leaders and organizations in order to inform the development of strategies aimed at reducing the prevalence of antimicrobial resistance and identifying appropriate treatment options for associated infections.
A-262 Analytical and Clinical Validation of a Multiplex RT-PCR based Mpox Assay
Authors: Upadhyay P , Reddy J , Singh V
Published: September 2023

Background

The 2022 non-endemic spread of Mpox in the western hemisphere was a unique public health challenge in the backdrop of the COID19 pandemic. To address the public health emergency where Mpox transmission was unlike previous instances, HealthtrackRX was one of the first independent diagnostics labs to develop a multiplexed RT-PCR based test for Mpox. In the present study analytical and clinical validation results for the Mpox RT-PCR test are presented.

Methods

The multiplexed pan-orthopox/pan-Mpox RT-PCR test was validated using inactivated Mpox (Clade I and II) viral samples establishing the limit of detection (LoD). Clinical validation of the test was performed against the FDA approved test at CDC and a commercially available pan-Orthpox assay. Sensitivity and specificity performance against interfering substance, pathogens and other poxviruses was also established. All statistical analysis were performed using R version 3.6.0.

Results

The multiplexed pan-Orthopox/pan-Mpox RT-PCR test successfully detected both Clade I and II Mpox and the LoD was established at 102 RNA copies/µl.The in-house developed Mpox test displayed 100% concordance against the FDA approved CDC pan-orthopox test and the pan-orthopox RT-PCR test from Thermo Fisher. The test showed no interference from a number of sexually transmitted pathogens and could successfully discern Mpox from several other poxviruses. With the exception of ethanol, no substances (from the FDA recommended list) interfered with the test performance. A total of 1712 patient samples were collected (July 25th, 2022, to February 1st, 2023) and tested for the presence of Mpox.

Conclusion

We have demonstrated the development, validation, and commercialization of a multiplexed RT-PCR based pan-orthopox/pan-Mpox diagnostic test for Mpox. Our data shows the feasibility of rapidly developing and deploying a PCR based test against an emerging infectious disease.
A-267 Evaluation of the Quidel Sofia 2 Rapid Lyme Test in a Modified Two-tier Testing Protocol
Authors: Lewandrowski K , Branda J , Turbett S , Lee-lewandrowski E
Published: September 2023

Background

Several Modified two-tier testing algorithms (MTTT) for Lyme disease involving sequential enzyme immunoassays (EIA) have been approved by the FDA as an alternative to conventional two-tiered testing using EIA followed by immunoblot. The MTTT algorithms are reported to be more sensitive than conventional two-tiered algorithm’s especially in early Lyme disease. The Quidel Sofia 2 Lyme assay utilizes lateral flow with fluorescence detection (FIA) providing a rapid on-demand instrument-read alternative to central laboratory batch mode testing We compared the Quidel assay as a first-tier test in an MTTT algorithm to the Zeus Scientific VlsE1/pepC10 IgG/IgM enzyme immunoassay (EIA) followed by the Zeus monovalent IgM and IgG EIA as the confirmatory test.

Methods

Serum specimens (n = 179) were obtained from consecutive samples sent to our clinical laboratory for Lyme serology testing. For the first-tier the samples were tested using the Zeus EIA VlsE1/pepC10 lgG/IgM test and the Quidel Sofia 2 Lyme FIA assay. Positive or equivocal first-tier tests were then tested using the Zeus monovalent IgM and IgG EIA as the confirmatory test.

Results

The positive percent agreement was 100%, the negative percent agreement 97.9 % with an overall agreement of 98.3%. The Kappa statistic was 0.945 (95% confidence interval 0.883–1.000 indicating “almost perfect” agreement).

Conclusion

The Quidel Sofia Lyme test performs well when compared to the Zeus test in a two-tiered testing MTTT algorithm. Obtaining samples to evaluate Lyme serologic tests can be challenging. Our data should prove useful for facilities considering the use of the Quidel assay.
A-274 Validation of Cefepime-Taniborbactam MIC Antimicrobial Susceptibility Test for MicroScan Dried Gram-Negative MIC Panels from a Multicenter Assessment of Enterobacterales and Pseudomonas aeruginosa
Authors: Garner O , Harrington A , Emery C , DesJarlais S , Diaz J , Chipman A , Hastey C
Published: September 2023

Background

Cefepime-taniborbactam is an investigational agent with activity against carbapenem and multidrug-resistant Enterobacterales and Pseudomonas aeruginosa.1 Given the need for accurate antimicrobial susceptibility testing results to support patient care decisions, a multicenter study was conducted with Enterobacterales and Pseudomonas aeruginosa clinical isolates on investigational MicroScan Dried Gram-negative MIC (MSDGN) panels with cefepime-taniborbactam.2

Materials/Methods

MSDGN panels were evaluated at three clinical sites by comparing MIC values obtained using MSDGN panels to MICs utilizing CLSI broth microdilution reference panels. The study included 490/491 Enterobacterales and 65 Pseudomonas aeruginosa clinical isolates tested using Prompt® and turbidity methods of inoculation during the combined efficacy and challenge phases. MSDGN panels were incubated at 35 ± 1°C and read on the WalkAway System, the autoSCAN-4 instrument, and visually at 16–20 h. Frozen reference panels were prepared according to CLSI/ISO methodology, incubated for 16–20 h and read visually.

Results

Essential agreement was calculated compared to MIC results from frozen reference panels for isolates tested in efficacy and challenge and found in the following table.

Conclusion

Cefepime-taniborbactam MIC results for Enterobacterales and Pseudomonas aeruginosa obtained with the MSDGN panel correlate well with MICs obtained using frozen reference panels in this multicenter study.Pending approval by the US Food and Drug Administration; not available for in vitro diagnostic use in the US. Not for Distribution in the US.Pending submission and clearance by the US Food and Drug Administration; not yet available for in vitro diagnostic use in the US.For Investigational Use Only. Performance characteristics of this product have not been established.Read methodEnterobacterales Essential agreement (EA) % (n/N)Pseudomonas aeruginosaEssential agreement (EA) % (n/N)PromptTurbidityPromptTurbidityWalkAway90.0 (441/490)99.2 (487/491)100.0 (65/65)100.0 (65/65)autoSCAN-494.3 (462/490)99.0 (486/491)98.5 (64/65)98.5 (64/65)Visually92.7 (454/490)99.2 (487/491)100.0 (65/65)100.0 (65/65)Abbreviations: Prompt, Prompt inoculation method, Turbidity, Turbidity inoculation method.
A-277 Health Economic Impact of use of GCAL Calprotectin Immunoassay for Early Detection of Infection in Intensive Care Patients
Authors: Jaquemar M , Larsson A , Havelka A
Published: September 2023

Background

Early diagnosis of bacterial infections in critically ill patients is challenging, as the clinical manifestation is non-specific. Neutrophil activation is a major response to bacterial infection and calprotectin an important marker for neutrophil mediated inflammation. Earlier studies have shown the ability of calprotectin to predict bacterial infections before onset of clinical symptoms. With early diagnosis of bacterial infections delayed treatment will be avoided as well as deterioration due to severe infections/sepsis.

Methods

A decision tree model is employed to estimate the impact of calprotectin analysis for early detection of bacterial infection and thus, the earlier start of antibiotic treatment compared to other diagnostic comparators such are white blood cell count, procalcitonin, C-reactive protein, and no testing. The analysis is based on patients admitted to an ICU in a Swedish hospital. The model allows for different diagnostic outcomes based on correctly and incorrectly diagnosis of bacterial infection and timing of antibiotic treatment: patient survival, length of stay in ICU and in general ward and total costs.

Results

The base-case results show that predictively measuring of calprotectin in an ICU, using GCAL® assay reduces total costs by approximately 13 000–18 000 EUR per patient, overall mortality rate by 0.11, and mean length of stay in an ICU and general ward by 1.3–2 days and 6–8 days, respectively.

Conclusion

The base-case scenario identified GCAL® Calprotectin Immunoassay as cost-effective for a patient cohort presenting in a Swedish ICU. Compared to the comparators, GCAL® saves total costs, reduces the mean duration of in-patient care, and reduces in-hospital mortality in those patients. In the sensitivity analysis, when key model inputs are varied, GCAL® Calprotectin Immunoassay remains the dominant option.
A-278 Development and Validation of Platform Independent, Turbidimetric Sars-CoV-2 Total Antibody Assay
Authors: Jaquemar M , Nilsen T , Safdari A , Haukebø A , Trosten E , Havelka A , Olsvik Ø
Published: September 2023

Background

The outbreak of the SARS-CoV-2 pandemic and continuous presence of the virus in the community require efficient tests for monitoring the anti-SARS-CoV-2 levels and management of the vaccination response in the population. Gentian AS, in collaboration with the University of Tromsø, has developed a quantitative SARS-CoV-2 antibody assay that captures the full immune response detecting antibodies targeting the S1-subunit with high sensitivity and specificity and is calibrated against the WHO international standard.

Methods

The immunoassay was developed and validated on turbidimetric instruments Cobas c501 from Roche and BS240 BS/240Pro from Mindray. Pre-pandemic samples from healthy donors or patients, were used for evaluation of clinical specificity. Samples from patients infected with Sars-CoV-2 virus or vaccinated against the virus were used for evaluation of clinical sensitivity.

Results

The assay has a calibration range from 0 to 1000 BAU/mL. No antigen excess was observed up to 2500 BAU/mL. Precision achieved a CV <20 % for samples with a concentration ≤ 165 BAU/mL, and <10 % for samples >165 BAU/mL. No clinically relevant cross reactivity towards 13 antibodies, including antibodies against other Corona viruses was observed. The assay was able to detect antibodies generated in response to different vaccines and Alpha, Beta, Gamma, Delta and Omicron virus variants. Sensitivity and specificity of the assay met the acceptance criteria set out from the MDCG 2021–21 guideline, ≥90% and >99% respectively.

Conclusion

The Gentian SARS-CoV-2 total antibody assay is a platform independent high-throughput assay with high sensitivity and specificity for assessment of antibody response after a natural infection and/or vaccination. The assay can ensure effective and reliable monitoring of the immunity and can be used for planning and management of the vaccination response in the community.