Performance Evaluation Analysis Research Articles

B-254 Analytical and Clinical Performance Evaluation of Plasma pTau217 in a Clinical Diagnostic Laboratory

Abstract Background Blood-based biomarkers provide an accessible and cost-effective tool for diagnosing Alzheimer’s disease (AD). Among these biomarkers, phosphorylated tau 217 (pTau217) shows promise for both AD diagnosis and differential diagnosis, as well as for facilitating access to emerging disease-modifying therapies. The ALZpath SIMOA pTau-217 v2 assay is a digital immunoassay designed for quantifying pTau-217 in human EDTA plasma samples. This study assesses the analytical performance of plasma pTau217 assays as a Laboratory Developed Test (LDT) appropriate for diagnostic application. Methods In this analytical study, we evaluate accuracy, precision, detection limits, linearity, and analyte stability. Plasma pTau217 levels were measured using the ALZpath pTau217 v2 assay on a single Quanterix HD-X SIMOA Analyzer platform at BC Neuroimmunology Lab. Inc. Vancouver, British Columbia, Canada. As a clinical testing laboratory, our validation procedures are in accordance with CAP and CLIA requirements, with a primary focus on adhering to CLSI guidelines for both analytical and clinical performance testing. To determine a reference range and cut-off, samples of Amyloid PET-confirmed cases (n=263) and healthy subjects between the ages of 55 and 95, with a roughly equal ratio of males to females (n=219), were tested. Results The ALZpath pTau217 assay demonstrates an analytical measurement range of 0.0046 - 3.4056 ng/L, with a limit of blank (LoB) of 0.0019 ng/L, a limit of detection (LoD) of 0.0046 ng/L, and a limit of quantification (LoQ) of 0.03 ng/L. Linearity spans from 0.06 to 1.75 ng/L, with repeatability showing intra-laboratory precision above LoQ ≤ 20% CV. Stability is maintained at 4⁰C for ≤ 1 week, at room temperature for ≤ 72 hrs, at -20⁰C for ≤ 2 weeks, and at -70⁰C for ≤ 3 weeks, with freeze/thaw cycles tolerated up to 6 times. Moreover, interference is not detected at the maximum concentrations tested for albumin, unconjugated bilirubin, biotin, hemoglobin, creatinine, and heterophilic antibodies. The reference range was determined using the 95% reference interval, resulting in 0.398 ng/L. ROC analysis yielded an AUC of 0.932 with a Youden index of 0.338 ng/L. At the Youden index, sensitivity was 90.0% with a specificity of 85.6%. Specificity reached 95.5% at the upper cut point of 0.471 ng/L, while sensitivity was 94.8% at the lower cut point of 0.242 ng/L. Conclusions The outstanding analytical performance of pTau217 supports its adoption as a reliable screening and diagnostic tool in clinical practice, aiding clinicians in the accurate diagnosis of AD.

B-202 Clinical and analytical performance evaluation of Savanna RVP4 panel versus three methodologies

Abstract Background Rapid molecular diagnosis became a key solution for healthcare institutions across the world, after COVID-19 pandemic. It has enabled diagnosis based on improved quality, accuracy, analytical sensitivity, and turnaround times for laboratory services. It also has positioned this methodology as a trusted technology for point-of-care settings. These solutions also allow to consolidate combinations of different pathogen detection in panels. This study assessed the analytical and clinical performance of the novel Savanna RVP4 panel against other available methodologies. Methods A prospective study was performed, considering 84 patient samples obtained from nasopharyngeal swabs. Samples were processed in parallel after collection, using Savanna RVP4, and either QIAstat-Dx Respiratory SARS-CoV Panel (59 samples), Sansure iPonatic (10 samples) and BioFire® Respiratory 2.1 (RP2.1) Panel (15 samples). Samples were collected in either MTU, commercial or homemade PBS. Results Overall clinical sensitivity and specificity were 96.43% and 99.64%, respectively for the aggregated panels (Table 1). By technology, the overall clinical sensitivity and specificity were 93.75% and 99.51% versus QIAstat, 100% and 100% versus Biofire, respectively. For iPonatic comparisons, no positive samples were processed and 100% of specificity was obtained. Cycle threshold (Ct) values for positive samples were compared using box plots. Ct values also showed slighlty differences, where means were lower for RSV and Flu A in Savanna (22 and 22.9 respectively) versus other PCR assays (22.5 and 24.5 respectively). For SARS-CoV-2, Ct values were higher versus other methods (19.8 vs 13.6). Conclusions Results obtained with Savanna RVP4 were comparable to those obtained with other methodologies, correlating with patient clinical symptoms. Samples showing disagreement for QIAstat comparison panel, in Flu A and RSV assays, corresponded to the same patient samples for the two methodologies, where Ct obtained in QIAstat were above 33. This evaluation also provides strong evidence supporting PBS usage for samples processed in Savanna RVP.

B-056 Clinical and Analytical Performance Evaluation of Two Immunoassays for the Detection of Mite Specific Serum IgE for Allergy Diagnosis

Abstract Background IgE-mediated allergic diseases can be considered a modern epidemic, with exponential growth mainly in industrialized countries. Diagnosis is usually based on detailed medical history, physical examination, skin or challenge test and the determination of allergen-specific serum IgE - a laboratory test that has become a high-value tool in the allergy patient's journey over the last three decades. As the identification of specific immunoglobulin E (sIgE) for a given allergen is important to aid in the allergy diagnosis, several methods for detecting IgE in vitro are available worldwide and, in recent years, there have been several improvements in laboratory methodologies bringing greater advances in terms of clinical and analytical performance. The study aims to evaluate the clinical performance and correlation between two different sIgE assays (IMMULITE® 2000 3gAllergy™ and ImmunoCAP) and their concordance with Skin Prick Test (SPT) and clinical history. Methods This prospective study was conducted with approximately 130 consecutive patients who underwent evaluation of allergic diseases in different centers in Brazil. Clinical data, blood samples, and SPT results were collected. With the blood samples, the allergens D1, D2 and D201 were evaluated using both methods (IMMULITE® 2000 3gAllergy™ and ImmunoCAP) and the data were evaluated in a correlation study and clinical concordance analysis. Results Qualitatively evaluating the sIgE results between the two immunoassays, at the cutoff point considered clinically significant (≥ 0.35 KU/L), a total agreement of 95.2% (D1); 95.1% (D2), 91.7% (D201) and 96.8% (Derp2) was observed. Semi-quantitatively evaluating through reactive interpretation, an agreement of 89.5% (D1); 91.06% (D2); 87.60% (D201) and 93.33% (Derp2) was observed. Spearman's correlation between the analytical methods was 0.85 (D1), 0.93 (D2), 0.68 (D201) and 0.76 (Derp2). When compared with the SPT results, a total agreement of 78.7% and 80.1% was obtained for 3gAllergy and ImmunoCAP, respectively, with slightly higher positive agreement for both methods. Conclusions The two methods have good agreement with each other, with greater differences when evaluated quantitatively. However, when compared to clinical history and skin prick test results, both perform very similarly with a few differences that may be caused by the difference in the assay design.

A-103 Analytical Performance Evaluation of Plasma NfL in a Clinical Diagnostic Laboratory

Abstract Background Neurofilament light chain (NfL) is a neuron-specific intermediate filament that is released at a consistent low level in normal individuals and increases with age and axonal injuries. NfL is a neurodegeneration biomarker in Alzheimer’s disease (AD), multiple sclerosis, stroke, traumatic brain injury and other neurodegenerative diseases (NDD). Here, we report the analytical performance of plasma NfL using high-sensitivity methodology in a clinical diagnostic laboratory. Methods The analytical performance, encompassing precision, detection limits, interference, and linearity, was evaluated. Plasma NfL levels were measured between July and October 2023 at Neurocode USA in Bellingham, WA, using a single Lumipulse G1200 instrument following CLSI guidelines, particularly for the utilization of the Fujirebio NfL Blood RUO assay as a laboratory-developed test for clinical analysis. A total of 100 healthy control samples, near the age of AD onset, were used to validate the reference ranges. Results The average plasma NfL concentrations varied from ≤ 8.4 to ≤ 37.9 ng/L among healthy individuals aged 20 to 80 years. The Plasma NfL assay exhibits analytical measurements, including a limit of blank (LoB) of 0.75 ng/L, a limit of detection (LoD) of 1.99 ng/ml, and a limit of quantification (LoQ) of 3.96 ng/L. Its linearity ranges from 11.08 to 741.58 ng/L, with intra-laboratory precision ≤ 9% CV. Stability is maintained at 4⁰C for ≤ 72 hours, at room temperature for ≤ 4 hours, at -20⁰C for ≤ 4 weeks, and at -80⁰C for ≤ 7 days, with freeze/thaw cycles tolerated within the specified time frame. Additionally, no interference was observed at the maximum concentrations tested for bilirubin, hemoglobin, and intralipid. Conclusions With a reference range between ≤ 8.4 to ≤ 37.9 ng/L and exceptional analytical performance, the measurement of plasma NfL on a state-of-the-art instrument using CLSI guidelines, can be useful in the diagnosis and monitoring of AD and other NDD.

THE FABRICATION OF MIP BASED ELECTROCHEMICAL SENSOR FOR THE DETERMINATION OF DOBUTAMINE

Objective: Dobutamine (DBT), one of the most common synthetic catecholamines, is important in the renal, cardiovascular, hormonal, and central nervous systems. In our study, it is proposed to produce the first MIP-based electrochemical sensor for DBT analysis. MIP(DBT)/GCE was developed by electropolymerization of 4-aminobenzoic acid (4-ABA) in the presence of DBT. Analytical performance and validation evaluation were performed on both standard solution and commercial serum samples. Material and Method: DBT was supplied by the Vem pharmaceutical company. For the preparation of 5 mM [Fe(CN)6]3-/4- solution, known amounts of potassium ferricyanide ([K3Fe(CN)6]) and potassium ferrocyanide (K4[Fe(CN)6].3H2O mixed in 0.1 M KCl solution. The 4-ABA was used to create the polymeric film in the presence of DBT. Electrochemical measurements were actualized in IVIUM compactStat.h potentiostat (Eindhoven, The Netherlands) using a three-electrode system consisting of Pt wire, Ag/AgCl reference electrode, and glassy carbon electrode (GCE). Result and Discussion: The MIP(DBT)/GCE sensor was applied to standard solution and commercial serum samples. When DBT concentrations were plotted against ΔI values, a linear response between 1×10-13 and 1×10-12 M was obtained in both environments. LOD results were found to be 0.087×10-13 M and 0.033×10-13 M in standard solution and commercial human serum, respectively. Recovery% and RSD% were found to be 99.68-100.32% and 1.38-1.66%, respectively.

Analytical performance evaluation of a new integrated clinical chemistry and immunoassay analyzer

BackgroundClinical laboratories perform a wide range of tests that are used by healthcare professionals to guide medical decision making. Use of automated analyzers in the clinical laboratory can improve patient care by not only reducing the turn-around-time (TAT) of results but also improving accuracy of the reported results by reducing human error. The aim of this study was to evaluate the performance characteristics of a new automated laboratory instrument, the Atellica® CI Analyzer, Model 1900, over a 3-month period in a European laboratory setting. MethodsAnalytical performance of 17 analytes (13 chemistry and four immunochemistry) was assessed by evaluating repeatability and within-laboratory precision using anonymized remnant serum samples. Method comparison studies were performed on the Atellica CI Analyzer and the Roche cobas® 6000. ResultsExcellent precision was observed with coefficients of variation (CVs) less than 2 % for repeatability and less than 3 % within-laboratory imprecision for most analytes. Comparison of select assays with the cobas 6000 system resulted in correlation coefficients ranging from 0.980 to 1.000. ConclusionThis is the first reported evaluation of the Atellica CI Analyzer in a clinical laboratory setting. The strong analytical performance of the Atellica CI Analyzer demonstrates that this instrument is suitable for routine clinical use.

Normatividad mexicana a la validación de métodos analíticos para cuantificar fármacos en matriz biológica. Ejemplo aplicativo: cuantificación de lamotrigina en plasma humano vía CLAR

Standardization organizations of different natures indicate how to obtain documented experimental evidence that certifies the validity of analytical methods to quantify drugs in the biological matrix for bioequivalence studies. The vast amount of information on this subject highlights its relevance in uniforming the procedures to achieve the desired objective, which can be applied by any laboratory that requires it. However, to avoid discrepancies in the interpretation and / or execution of the various forms of analytical performance evaluation by the authority concerning the international information provided, local regulations are issued as mandatory, highlighting critical situations with discriminatory criteria. This paper presents the minimum analytical performance characteristics and the acceptance criteria required (according to Mexican regulations) to demonstrate that an analytical method is valid to quantify drugs in a biological matrix by HPLC (high-performance liquid chromatography) for a research study at a graduate-level educational institution. It is emphasized that the analytical parameters to be met under this standard consider the specific aspects of the technique and biological sample. For this purpose, a method developed and validated by our research group is used as an example for studying the biological sample. For this purpose, a method developed and validated by our research group to quantify lamotrigine in human plasma for monitoring purposes is used as an example. The performance characteristics of the NOM-177-SSA-2013 applied to the validation of the developed method demonstrate the validity and application of the method for the desired objective.

Analytical and clinical performance evaluation of a new NT-proBNP assay

BackgroundThe study evaluated the performance of the Mindray N-terminal pro-B-type natriuretic peptide (NT-proBNP) in a healthy population in China, focusing on creating a reference range for future clinical applications adjusted according to different demographics.MethodsThe study measured NT-proBNP in 2277 healthy individuals. We analyzed age and sex-stratified data, performed precision, accuracy, linearitcvy, and detection limit studies, and evaluated method comparison and consistency between Roche and Mindray assays on 724 serum samples. We used Excel 2010, Medcalc, and GraphPad Prism 9.ResultsIn males, the 97.5th centile NT-proBNP concentration at age < 45, 45 to 54, 55 to 64, 65 to 74 and ≧ 75 were 89.4 ng/L, 126 ng/L, 206 ng/L, 386 ng/L and 522 ng/L, respectively. In females, the concentration of NT-proBNP at the same age was 132 ng/L, 229 ng/L, 262 ng/L, 297 ng/L and 807 ng/L, respectively. The repeatability precision coefficient of variation (CV%) for NT-proBNP was between 0.86 and 1.65 in analytical performance. In contrast, the reproducibility precision (CV%) for NT-proBNP was between 1.52 and 3.22, respectively. The study found a bias of accuracy of 3.73% in low-value samples (concentration: 148.69) and 7.31% in high-value samples (concentration: 1939.08). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 125 ng/L were 96.6%, 92.3%, 84.2%, and 98.5%, respectively. In contrast, those of 300 ng/L were 94.0%, 98.2%, 95.7% and 97.5%, respectively.ConclusionsThe Mindray NT-proBNP assay showed increased levels in both males and females with age, with higher levels in women. It performs well and aligns with manufacturer specifications. We recommend adjusting cutoff values based on demographic factors.

MSK-ACCESS powered with SOPHiA DDM: Performance analysis of a decentralized MSK-ACCESS solution.

e15063 Background: Blood plasma cell-free DNA (cfDNA) testing of cancer patients allows for genomic profiling when tissue sampling is too invasive or of insufficient quality. This approach has demonstrated clinical utility to identify treatment targets, screen for resistance and monitor disease burden. MSK-ACCESS (Memorial Sloan Kettering – Analysis of Circulating cfDNA to Evaluate Somatic Status) is a validated, high sensitivity cfDNA assay employed at MSK to identify biologically actionable tumor alterations in clinical care. SOPHiA GENETICS is developing a decentralized solution of this assay that incorporates major features of MSK-ACCESS such as molecular barcoding, duplex-based variant calling, the inclusion of tumor-informed prior knowledge and identification of somatic alterations through the removal of both germline and clonal hematopoiesis (CH) variants. Here, we present the results of a performance study obtained during product development. Methods: A cohort of 24 plasma cfDNA and matched white blood cell (WBC) DNA samples were collected from patients with solid tumors and processed at MSK according to the validated standard operating procedures and bioinformatic analyses. In parallel, for the same set of materials libraries were constructed at SOPHiA GENETICS using the proprietary CUMIN molecular identifiers, captured with probes targeting the updated MSK-ACCESS v2 set of 146 genes and sequenced on an Illumina NovaSeq 6000. Variants were called using a duplex-aware approach by SOPHiA GENETICS and germline and CH variants were identified and filtered by paired cfDNA – WBC DNA analysis. Accuracy of the decentralized “MSK-ACCESS powered with SOPHiA DDM” solution was assessed through concordance to the orthogonal results obtained by MSK. Results: A total of 104 somatic SNV/Indels were detected with variant allele fractions (VAF) ranging from 0.1% to 97.0% with a median of 5 variants per sample. The positive percent agreement (PPA) for all variants above the limit of detection of the original MSK-ACCESS assay was 98.9% with 99.98% specificity. For the subset of prior-knowledge variants PPA was 95.6% down to 0.1% VAF. A total of additional 59 variants with ≤ 15% VAF were found both in cfDNA and WBC and assigned as CH-derived. Importantly, these occurred not only in CH-associated genes but also in common oncogenes such as BRCA1/2 and ERBB2, highlighting the utility of matched WBC analysis to correctly identify somatic variants. Conclusions: The results demonstrate that the decentralized “MSK-ACCESS powered with SOPHiA DDM” solution exhibits a high degree of agreement to the results achieved by MSK. Further studies will be conducted to expand the analytical performance evaluation.

Analytical performance evaluation of the Mindray enzymatic assay for hemoglobin A1c measurement

Hemoglobin A1c (HbA1c) plays a crucial role in diabetes management. We aimed to evaluate the analytical performance of a new enzymatic method kit for HbA1c measurement. The performance of the enzymatic method, including precision, accuracy, and linearity, was evaluated. Moreover, the interference effect from conventional interferents, Hb derivatives, Hb variants, and common drugs were assessed. In addition, the agreement of HbA1c results was compared between enzymatic methods, cation-exchange high-performance liquid chromatography (HPLC), and immunoassays. The intra-assay, between-assay, and total precision of HbA1c were all lower than 2%. HbA1c showed good linearity within the range of 3.96–20.23%. The enzymatic assay yielded results consistent with the external quality control samples, with a bias of less than ± 6% from the target values. The enzymatic method showed no interference from bilirubin, intralipid, vitamin C, Hb derivatives, common Hb variants, as well as antipyretic analgesics and hypoglycemic drugs. The HbA1c results of the enzymatic assay showed good agreement and accuracy compared to those obtained from the HPLC method and the immunoassay. The enzymatic method kit performed on the BS-600M chemistry analyzer is a reliable and robust method for measuring HbA1c. It is suitable for routine practice in clinical chemistry laboratories.

A Microfluidic Paper-Based Lateral Flow Device for Quantitative ELISA

This study presents an innovative lateral flow microfluidic paper-based analytical device (μPAD) designed for conducting quantitative paper-based enzyme-linked immunosorbent assays (p-ELISA), seamlessly executing conventional ELISA steps in a paper-based format. The p-ELISA device utilizes a passive fluidic circuit with functional elements such as a multi-bi-material cantilever (B-MaC) assembly, delay channels, and a buffer zone, all enclosed within housing for autonomous, sequential loading of critical reagents onto the detection zone. This novel approach not only demonstrates a rapid assay completion time of under 30 min, but also boasts reduced reagent requirements, minimal equipment needs, and broad applicability across clinical diagnostics and environmental surveillance. Through detailed descriptions of the design, materials, and fabrication methods for the multi-directional flow assay (MDFA), this manuscript highlights the device’s potential for complex biochemical analyses in a user-friendly and versatile format. Analytical performance evaluation, including a limit of detection (LOD) of 8.4 pM for Rabbit IgG, benchmarks the device’s efficacy compared to existing p-ELISA methodologies. This pioneering work lays the groundwork for future advancements in autonomous diagnostics, aiming to enhance global health outcomes through accessible and reliable testing solutions.

Fluorescence-Based Lateral Flow Immunoassay for Quantification of Infliximab: Analytical and Clinical Performance Evaluation.

Therapeutic drug monitoring of infliximab (IFX) can improve treatment outcomes; however, the temporal gap between drug concentration monitoring and subsequent availability restricts its practical application. To address this issue, an automated monitoring method, AFIAS IFX, was developed to rapidly and accurately analyze IFX concentration in blood. The analytical and clinical performances of this method were assessed to establish its clinical utility. The analytical performance of AFIAS IFX was evaluated according to Clinical and Laboratory Standard Institute guidelines. For clinical validation, AFIAS IFX was compared with 3 established enzyme-linked immunosorbent assay kits (LISA TRACKER, RIDASCREEN, and ImmunoGuide) using 100 consecutive samples from 28 patients treated with IFX. Passing-Bablok regression and Bland-Altman analyses were performed to compare the methods. The detection and quantification limits of AFIAS IFX were 0.12 and 0.20 mcg/mL, respectively. Furthermore, AFIAS IFX analyzed samples within 10 minutes for concentrations up to 50 mcg/mL, exhibiting reproducibility (coefficient of variation [CV] ≤7.8%) and accuracy (recovery 98%-101%) with serum, plasma, and whole blood samples. Clinically, it exhibited a good correlation with the 3 established enzyme-linked immunosorbent assay kits. For patients treated with Remicade (IFX), the Passing-Bablok regression slope was 1.001-1.259, with a mean difference of -1.48 to 0.28 mcg/mL. For patients treated with CT-P13, the Passing-Bablok regression slope was 0.974-1.254, with a mean difference of -2.44 to 0.15 mcg/mL. AFIAS IFX, a novel fluorescence-based lateral flow assay, exhibited excellent performance in analyzing IFX trough levels and is a potentially powerful tool for therapeutic drug monitoring in clinical settings, with opportunities for further development.

Evaluation of the diagnostic performance of an immunochromatographic test for Chlamydia trachomatis

ObjectivesTo evaluate the diagnostic performance of different brands of immunochromatographic test (ICT) reagents for Chlamydia trachomatis using homogenized samples to provide a reference for reagent quality control. MethodsEight commercially available ICT reagents were evaluated, of which three used the latex method and five used the colloidal gold method. Analytical performance evaluation using a pure culture broth of C. trachomatis, as well as clinical application validation using cervical epithelial cell samples acquired from the research subjects, were conducted. The concentration of C. trachomatis was quantified using a nucleic acid amplification test. ResultsThe limit of detection (LOD) of different ICT reagents in the analytical performance evaluation varied from 9.5 × 103 to 1 × 105 IFU/mL, and only one reagent met the LOD specified in the manufacturer's instructions. Likewise, only one reagent in the clinical application validation achieved the analytical LOD, four reagents were 2.1–4.2-fold of the analytical LODs, and three reagents failed to detect positive results in clinical samples. ConclusionsThe diagnostic performance of different methods and different brands of ICT reagents in clinical practice was different from the manufacturer's instructions and the results of laboratory evaluation. The diagnostic performance of reagents should be evaluated before they are actually used in clinical practice.

Analytical and clinical performance evaluation of surelite 8 for high-sensitivity cardiac troponin I assay

Analytical and clinical performance evaluation of surelite 8 for high-sensitivity cardiac troponin I assay

Analytical performance evaluation of three sepsis related assays on the Atellica CI analyzer

Analytical performance evaluation of three sepsis related assays on the Atellica CI analyzer

Analytical performance evaluation of four assays used for diabetes on the Atellica CI analyzer

Analytical performance evaluation of four assays used for diabetes on the Atellica CI analyzer

Analytical performance evaluation of five chemistry assays on the Atellica CI analyzer

Analytical performance evaluation of five chemistry assays on the Atellica CI analyzer

Analytical performance evaluation of breast and ovarian cancer antigen assays on the Atellica CI analyzer

Analytical performance evaluation of breast and ovarian cancer antigen assays on the Atellica CI analyzer

Analytical performance evaluation of three major immunoglobulins assays on the Atellica CI analyzer

Analytical performance evaluation of three major immunoglobulins assays on the Atellica CI analyzer

Analytical performance evaluation of two therapeutic drug monitoring assays on the Atellica CI analyzer

Analytical performance evaluation of two therapeutic drug monitoring assays on the Atellica CI analyzer