Immunoassay System Research Articles

Loop-Mediated Isothermal Amplification Assay for the Detection of Citrus Canker Causing Bacterial Variant, Xanthomonas citri pv. citri Aw Strain.

Citrus canker, a highly transmissible bacterial disease, has three major types, with Asiatic canker (Canker A), caused by Xanthomonas citri pv. citri (Xcc A), being the most widespread and severe, affecting most citrus varieties. Xcc A has two mild variants, Xcc A* and Aw with a limited host range, reported in Southwest Asia and Florida, respectively. Since 2015, the canker caused by Xcc Aw has been being reported in the Rio Grande Valley of South Texas where the Texas commercial citrus industry is located. In 2016, a more severe Canker A was reported in the upper Texas gulf coast region, north of the Rio Grande Valley, posing a potential threat to the Texas citrus industry. Given that existing diagnostic methods cannot reliably distinguish Xcc Aw from Xcc A, we developed a loop-mediated isothermal amplification (LAMP) assay specific to Xcc Aw (LAMP-Aw) for rapid, field-based identification of this bacterial variant. The detection limit of LAMP-Aw was ~4.52 Log10 copies of the target molecule. This study also evaluated the field applicability of the LAMP-Aw assay by coupling the LAMP-Aw assay with a lateral flow immunoassay system.

Fluorescence Immunoassay of Prostate-Specific Antigen Using 3D Paddle Screw-Type Devices and Their Rotating System.

In this paper, we present a sensitive and highly reproducible fluorescence immunosensor for detecting PSA in human serum. A unique feature of this study is that it uses creatively designed paddle screw-type devices and their custom-made rotating system for PSA immunoassay. The paddle screw devices were designed to maximize the surface-to-volume ratio over which the immunoassay reaction could occur to improve detection sensitivity. This paddle screw-based immunoassay offers an accessible and efficient method with a short analysis time of less than 30 min. Active rotation of the paddle screw plays a crucial role in fast and accurate analysis of PSA. Additionally, a paddle screw-based immunoassay and subsequent fluorescence detection using a custom prototype fluorescence detection system were compared to a typical well plate-based immunoassay system. Results of PSA detection in human serum showed that the detection sensitivity through the paddle screw-based analysis improved about five times compared to that with a well plate-based analysis.

Advancements in electrochemical immunosensors towards point-of-care detection of cardiac biomarkers.

Cardiovascular disease remains the leading cause of death worldwide, with mortality rates increasing annually. This underscores the urgent need for accurate diagnostic and monitoring tools. Electrochemical detection has emerged as a promising method for swiftly and precisely measuring specific biomarkers in bodily fluids. This approach is not only cost-effective and efficient compared to traditional clinical methods, but it can also be tailored to detect individual biomarkers, which makes it particularly well-suited for point-of-care (POC) applications. The ability to conduct testing at the point of care is crucial for timely interventions and personalized disease management, empowering healthcare providers to tailor treatment plans based on real-time biomarker data. Thanks to recent advancements in nanomaterials, we've seen significant progress in electrochemical detection, leading to the development of specialized rapid immunoassay systems. These systems utilize specific antibodies to target molecules, expanding the range of detectable biomarkers. This innovation has the potential to revolutionize the diagnosis and treatment of cardiovascular diseases by enhancing detection sensitivity and specificity. Ultimately, these advancements aim to improve patient outcomes by enabling earlier diagnosis, more precise monitoring, and personalized therapeutic interventions, which will contribute to more effective management of cardiovascular health globally.

Monitoring Estradiol and Progesterone Content of Saanen Goats During Pregnancy

Saanen is a specialized dairy goat breed originating from Switzerland, imported and encouraged to be raised in Vietnam. This article presents the results of a survey of estradiol and progesterone levels during pregnancy in Saanen goats at the Binh Duong Large Livestock Research and Development Center. After monitoring mating, goats were sampled for blood every 7 days until birth, at 6-8 am. Hormone levels were determined by electrochemiluminescence assay, with the Cobas E601 immunoassay system. The results showed that after 14 days of conception, progesterone levels gradually increased (3.21±0.36 ng/ml) and shifted to higher levels, peaking on day 70 of pregnancy (12.28±0.52 ng/ml) (in the 1-2 years old group); corresponding values were 3.18±0.75-11.88±0.92 ng/ml (in the 3-4 years old group). The high value range was maintained throughout pregnancy and decreased rapidly in the 14-21 days before birth in both age groups. Estradiol, maintained at low concentrations from 0.73±0.35 to 2.65±1.25 pg/ml (in the 1-2 years old group); from 0.98±0.48 to 3.27±1.95 pg/ml (in the 3-4 years old group) in the first 21 days of pregnancy and then gradually increased to above 10 pg/ml (in both age groups) on day 28. Estradiol continued to increase and reached a maximum level (205.48±32.81 pg/ml) in group 1 on day 126 and had an average value below 10 pg/ml within 1-2 days after giving birth. The results of this study help diagnose pregnancy, predict gestational age for effective reproductive management, and serve as a reliable reference when using assisted reproductive tools and strategies to improve reproductive performance in goats.

B-008 An Evaluation of the Analytical Performance of the New Beckman Coulter DxC 500i Clinical Analyzer

Abstract Background The DxC 500i Clinical Analyzer* is Beckman Coulter’s latest integrated Clinical Chemistry and Immunoassay analyzer. It provides reliability, scalability, and workflow efficiency via a flexible independent maintenance mode, increased uptime, and a dynamic sample handler to optimize sample management. Standard Beckman Coulter Chemistry and Immunoassay consumables and reagents ensure network standardization and commutability. The purpose of this study was to evaluate the analytical performance of the new DxC 500i analyzer and to compare the performance against the Beckman Coulter stand-alone Clinical Chemistry and Immunoassay analyzers on the market. Methods To assess performance over a range of assay methodologies, several DxC 500i Beckman Coulter Immunoassays and Chemistry assays were evaluated. Precision was assessed using human samples following CLSI EP05-A3 guidelines. Linear range was assessed following CLSI EP06-A guidelines. Method Comparison and Bias Estimation studies compared the DxC 500i Clinical Analyzer against the Access 2 Immunoassay System, the AU480 and the DxC 700 AU Clinical Chemistry analyzers, following CLSI EP09c-ED3 guidelines. To investigate carryover potential as samples are processed across the integrated system, a carryover study was designed. This focused on evaluating potential sample-to-sample carryover caused by the AU sample probe and its effects on immunoassay samples during reflex scenarios. Results DxC 500i Chemistry results: Glucose Serum (OSR6x21) Assessments of repeatability and within laboratory precision at multiple critical analyte concentrations showed total imprecision of <3% and within-run imprecision of <3%. The Glucose serum assay demonstrated acceptable linearity throughout the 10-800 mg/dL analytical measuring range. Method comparison studies compared the DxC 500i analyzer against the AU480 and DxC 700 AU systems. A Weighted Deming regression of serum patient samples (n>100 measured across the analytical range) yielded a 0.986 slope, 0.227 mg/dL intercept, and R=0.9999 correlation coefficient against the DxC 700 AU and a 0.995 slope, 0.356 mg/dL intercept, and R=0.9999 correlation coefficient against the AU480. DxC 500i Immunoassay results: Cortisol (33600) Beckman Coutler’s Cortisol assay exhibited total imprecision of <12%CV at <5 μg/dL or <10CV% at ≥5 μg/dL for serum. The Cortisol assay demonstrated acceptable linearity throughout the 0.4-60 μg/dL analytical measuring range. A method comparison study compared the DxC 500i against the Access 2 system. A Weighted Deming regression of serum patient samples (n>100 measured across the analytical range) yielded a 0.9785 slope, 0.2764 μg/dL intercept, and R=0.9932 correlation coefficient. DxC 500i Carryover Assessment The Total βhCG (5th IS) assay was used to evaluate the potential of chemistry analyzer to immunoassay analyzer sample carryover. The study used High hCG serum samples (>1,000,000 mIU/mL) and Low hCG serum samples (4-6 mIU/mL). The DxC 500i exhibited a cumulative carryover of ≤2 parts per million (PPM) for serum. Conclusions These studies demonstrate excellent analytical performance for the new Beckman Coulter DxC 500i Clinical Analyzer* and confirm comparable performance to current Beckman Coulter standalone Clinical Chemistry and Immunoassay analyzers on the market. *Pending clearance by the United States Food and Drug Administration; not yet available for in vitro diagnostic use in the U.S. Product availability and regulatory status depends on country registration per applicable regulations.

A-306 High Sensitivity Capability of an Anti-müllerian Hormone Assay on the Beckman Coulter DxI 9000 Immunoassay Analyzer*, a Next Step Toward Enabling Ovarian Failure Staging?

Abstract Background Measurement of anti-müllerian hormone (AMH) has proven value in the evaluation of ovarian reserve using assays such as the Beckman Coulter Access AMH assay. If improved sensitivity of AMH measurement can be achieved, enhanced clinical utility during the assessment of reproductive aging and ovarian response to enable staging of ovarian failure is possible (Practice Committee of the American Society of Reproductive Medicine 2020, Cappola et al. 2023). The Beckman Coulter DxI 9000 Immunoassay Analyzer* has been designed with new technology that can be leveraged to improve assay sensitivity. Such technological advancements include the new Lumi-Phos PRO chemiluminescent substrate which yields markedly increased signal-to-noise, a new luminometer with increased dynamic range, and improved low-volume pipetting capabilities. Data herein summarize results from analytical verification studies of the Access AMH assay on the DxI 9000 Immunoassay Analyzer. Results demonstrate an example of DxI 9000 technologies enabling sensitivity claims that are up to 20-fold improved. * The official name is DxI 9000 Access Immunoassay Analyzer. Methods A method comparison study was performed based on CLSI guideline EP09c, 3rd ed. to compare results for the Access AMH assay on DxI 9000 to the predicate device, the Access AMH assay on the Access 2 Immunoassay System. Within-laboratory precision was also evaluated following CLSI EP05-A3. Finally, performance at low analyte levels was evaluated following CLSI EP17-A2, and linearity was evaluated following CLSI EP06-Ed2. Results Method comparison of the Access AMH assay on DxI 9000 compared to the Access AMH assay on the Access 2 yielded excellent agreement with a Passing-Bablok slope of 1.02 for N=126 samples. Further, bias estimates for a number of key medical decision points suggest minimal bias (≤ 2%) across the assay range, and minimal non-linearity was observed. 20-day imprecision studies yielded CV’s between 2 and 5% across a broad range of concentrations evaluated. Sensitivity studies yielded estimates of limit of quantitation (LoQ) between 0.001 and 0.003 ng/mL. This represents an approximately 10- to 20-fold improvement in sensitivity claims compared to the AMH assay on the Access 2 and other commercially available automated immunoassay analyzers. Conclusions The data herein present performance data for the Access AMH assay on the DxI 9000 Immunoassay Analyzer. The assay demonstrates excellent accuracy relative to the predicate device, while showing good linearity and imprecision. Of note, the Access AMH assay exhibits exceptional low-end performance on the DxI 9000 analyzer as demonstrated by the ability to enable sensitivity claims that are up to 20-fold improved in comparison to existing immunoassays for the measurement of AMH. The sensitivity capabilities of the Access AMH assay on DxI 9000 suggest an opportunity for the addition of further intended uses for scenarios where extremely low AMH measurements can provide additional value of clinical significance. Further studies are needed to fully understand additional clinical utilities of the Access AMH assay with high sensitivity capability on DxI 9000, including the assessment of reproductive aging for menopause diagnosis or ovarian response for fertility treatment.

B-078 Serodiagnosis of Rheumatoid Arthritis Using the New Accentis Chemiluminescence Immunoassay Platform for Anti-CCP Antibody Detection

Abstract Background Rheumatoid arthritis (RA) is one of the most common autoimmune diseases and the most frequent chronic inflammatory arthropathy. Reliable diagnosis at the earliest possible stage is indispensable to keep the disease under control with suitable therapy and to prevent irreversible joint damage. Autoantibodies against cyclic citrullinated peptides (CCP) are a highly specific marker for RA with relevance for (differential) diagnosis, prediction and prognosis. In this study, we investigated the clinical and analytical performance of a newly developed anti-CCP chemiluminescence immunoassay (ChLIA) system. Methods Serum samples from 170 patients with clinically confirmed RA and from a control panel of 274 patients with other diseases were analyzed using the EUROIMMUN Anti-CCP ChLIA (IgG), which was processed on the fully automated random-access system Accentis (EUROIMMUN). The results were compared with those obtained with the EUROIMMUN Anti-CCP ELISA (IgG) with regard to sensitivity, specificity and inter-assay concordance. Results The ChLIA achieved a sensitivity of 71.2% (121/170) and a specificity of 97.4% (267/274), while the ELISA was less sensitive (67.5%, 114/170) and specific (96.4%, 264/274). The qualitative results showed positive and negative agreement rates between the two assays of 92.7% (115/124) and 95.9% (307/320), respectively, resulting in 95.0% (422/444) overall agreement and a kappa score (0.878) indicating near perfect agreement. Conclusions The new Accentis ChLIA showed improved sensitivity and specificity for the detection of anti-CCP antibodies compared to the corresponding ELISA. Given the enhanced clinical performance and the practical benefits of using a random-access system, this ChLIA platform can effectively support the diagnosis of RA.

B-038 A Novel Ultrasensitive Single-Molecule Counting Technology for Quantitation of Low Abundance Biomarkers

Abstract Background There is a need for sensitive, robust, and scalable analytical methods for accurate, early detection of disease using less invasive sampling methods. Often, smaller volumes and low marker concentrations present challenges to achieving sufficient sensitivity and accuracy with traditional immunoassay methods. This is particularly the case for measuring markers for Alzheimer's and other neurological diseases in blood, where levels are typically at much lower concentrations than in CSF. Here we introduce a novel ultrasensitive technology for flow-based single molecule detection in an optofluidic chip. We have developed an Ultrasensitive Detection Module (UDM) device and optofluidic cartridge that enable easy integration of this technology into existing immunoassay systems. UDM sensitivity data is shown for three prototype biomarker assays in comparison to the Lumipulse G1200 (Fujirebio Inc., Japan). We also present analytical validation data for three Alzheimer’s Disease plasma biomarker assays developed on a fully automated benchtop analyzer with integrated UDM detector. Methods Ultrasensitive detection is achieved by integrated low-loss waveguide in an optofluidic chip that enables maximal excitation of fluorescent molecules traveling through a narrow fluidic channel. The resulting high-intensity emission is detected as a single digital event, enabling individual molecules to be counted without need for amplification. Fluorescence-based immunoassays were developed for detection with the UDM using high performance monoclonal antibodies and reagents (Fujirebio Inc., Japan). Capture antibodies were immobilized on magnetic particles and detection antibodies conjugated to a fluorescent reporter construct (“reporter-Ab”). Multiple incubation and wash steps were followed by dissociation of immune complexes and separation of reporter-Ab from magnetic particles. Released reporter-Ab molecules were injected into the UDM device for digital detection. Signal to noise performance was evaluated in the UDM using reporter construct alone (no assay), as well as for prototype PSA, IL-6, and TSH assays, to establish baseline performance for analytical sensitivity. Plasma assays for pTau181, Aβ1-40, and Aβ1-42 were developed and optimized for the automated benchtop analyzer and validated for analytical sensitivity (LOD/LOQ), linearity, parallelism, precision and repeatability using clinical samples. Results Detection signal-to-noise testing of the reporter construct alone (no immunoassay) demonstrated up to 1000-fold higher sensitivity than the Lumipulse G1200. Prototype assays for PSA, TSH, and IL-6 showed up to 118-fold, 36-fold, and 80-fold higher signal to noise ratio, respectively, when compared to the Lumipulse G1200. Plasma assays for pTau181, Aβ1-40, and Aβ1-42 showed preliminary LLOQs calculated at 0.03 pg/mL, 0.17 pg/mL and 0.37 pg/mL, respectively. Conclusions We have developed a new single molecule counting platform able to detect neurological biomarkers at sub-pg/ml levels in plasma, with the potential to provide sensitive and accurate diagnostic testing of low abundance biomarkers in blood. Such technologies can create new clinical value through higher detection sensitivity and accuracy in areas like Alzheimer’s and other neurological diseases, supporting clinical research and translation to clinical practice.

B-267 Validation of the Newly Developed Fully Automated Chemiluminescent Enzyme Immunoassay (CLEIA) Reagent for Measurement of Cyclosporine in the Blood

Abstract Background Cyclosporine (CsA) is an immunosuppressive drug requiring therapeutic drug monitoring (TDM) for its narrow-ranged medication level. Approximately 60% of CsA in the blood exist as molecular complexes with proteins like cyclophilin in lymphocytes and erythrocytes. Measurement of CsA in the blood by immunoassay or liquid chromatography-tandem mass spectrometry (LC-MS/MS) requires an extraction process for CsA from the whole blood specimen, which is often manual complicated and time-consuming process causing a risk of variation in the measurement values among different operators. In addition, the small (cyclic polypeptide composed of 11 amino acids) and hydrophobic property of CsA, make it difficult to establish antibodies for a sandwich immunoassay. In this study, we have validated a novel fully automated sandwich immunoassay reagent for measurement of blood CsA that used a combination of newly-established CsA antibodies and iTACT® (immunoassay for total antigen including complex via pretreatment) technology. Methods The reagent was developed and validated on a fully automated immunoassay system, LUMIPULSE® L2400 (FUJIREBIO INC). Twenty uL whole blood specimens are sampled after mixed with suction/discharge stirring to prevent that blood cells settle to the bottom of a container on the analyzer, and then treated with a pretreatment solution to obtain free CsA. The treated samples are assayed by a two-step sandwich immunoassay. Limit of Detection (LoD), Limit of Quantitation (LoQ), within-laboratory precision, linearity, no interference, and the correlation of this assay and LC-MS/MS were validated, following the current CLSI guidelines protocols. Data were analyzed using Microsoft Excel statistical tool Analyse-it. Results The LoD and the LoQ were 2.7 ng/mL and 10.8 ng/mL respectively. The within-laboratory precision showed CV 1.6-2.9 %. Linearity was demonstrated over the range 13.1-2381.5 ng/mL. No interference was observed with unconjugated (≤19.7 mg/dL) or conjugated bilirubin (≤20.1 mg/dL), chyle (≤1480 FTU), RF (rheumatoid factor, ≤1000 IU/mL), and HAMA (human anti-mouse antibody, ≤1010 ng/mL). The correlation coefficient and the regression slope of this assay and LC-MS/MS were 1.0 and 1.0, respectively (N=120). Conclusions The performance of our novel CsA assay, which use LUMIPULSE L2400, was satisfactory for routine analysis. A unique fully-automated process, including the pretreatment process of whole blood specimens, for measurement would contribute the low LoQ and the low Within-laboratory CV. In addition, the results are obtained in 35-minute. We expect this novel immunoassay could reduce the burden on operators and turnaround time.

B-077 F-actin as a New Marker Antigen on an Established Multiparametric Immunoassay Profile for Liver Diseases

Abstract Background Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) are severe diseases with heterogenous manifestations, which affect people of all populations and age groups. Diagnosis and differentiation from other liver diseases such as primary sclerosing cholangitis (PSC) remain a substantial challenge for hepatologists. Since AIH and PBC are caused by different sets of autoantibodies, we previously developed a line blot for the parallel detection of all relevant parameters. We now added the AIH-specific antigen filamentous actin (F-actin) to this established liver immunoassay profile. Methods Sera from 15 patients with AIH, 15 patients with overlap AIH/PBC or AIH/PSC, 32 patients with PSC, 53 patients with PBC, 4 patients with non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH), 30 patients with hepatitis B infection and 79 patients with hepatitis C infection as well as sera from 150 blood donors were examined using the EUROLINE line immunoassay system (EUROIMMUN autoimmune liver diseases 9 Ag plus F-actin (IgG); contains the PBC-relevant antigens AMA-M2, M2-3E (BPO), Sp100, PML and gp210, the AIH-associated antigens LKM-1, LC-1 and SLA/LP and F-actin as well as Ro52). The newly included F-actin antigen was polymerized from human globular actin (G-actin) and assessed by sedimentation analysis and dynamic light scattering. The scan software EUROLineScan (EUROIMMUN) was used to automatically determine presence and intensity of the resulting bands on the blot. Results Quality assessment revealed successful polymerization of F-actin. Autoantibodies against this newly developed F-actin antigen were detected in 53.3% of sera from AIH patients and 40% of AIH+PBC/AIH+PSC overlap patients. 93% of these positive sera did not contain other autoantibodies associated with AIH. Only one PSC patient (3.1%), two patients with hepatitis C (2.5%) and two blood donors (1.3%) also showed anti-F-actin positivity. All tested sera of PBC, NAFLD/NASH and hepatitis B patients were evaluated as anti-F-actin negative. Conclusions The addition of F-actin to the established multiparametric EUROLINE profile for the simultaneous and monospecific detection of AIH- and PBC-relevant autoantibodies is a great advance for routine diagnostics of patients with symptoms associated with various liver diseases.

Serum TNFα and IL-17A levels may predict increased depressive symptoms: findings from the Shika Study cohort project in Japan

BackgroundLow-grade systemic inflammation may be a key player in the immune activation that has been reported for mental health deterioration. We hypothesised that elevated serum levels of inflammatory cytokines increase neuroinflammation and exacerbate depressive symptoms.MethodsThe participants were part of a cohort study for whom data was available for both 2015 and 2019. In 2015, blood samples were collected from 232 participants. Their depressive symptoms were assessed both 2015 and 2019 using the Centre for Epidemiologic Studies Depression Scale (CES-D) (n = 33). The multiplex immunoassay system (Luminex® 200) was used to measure the serum concentrations of IL-6, IL-10, IL-12, IL-17A and TNFα. Data were analysed using linear models with the level of significance considered to be p < 0.05.ResultsAfter controlling for age, BMI, smoking and alcohol consumption, in 2015 the serum concentrations of IL-17A and TNFα in 2015 were significantly positively associated with the CES-D scores of women (standardised β (B) = .027, p < 0.01 and B = 0.26, p < 0.01, respectively). The serum concentrations of IL-17A and TNFα of men were significantly positively associated with the CES-D scores of 2019 (B = 0.62, p = 0.02 and B = 0.59, p = 0.02, respectively).ConclusionsIn this cross-sectional study, we found a significant positive correlation between the depressive symptoms and serum TNFα and IL-17A levels of women. In addition, our longitudinal findings suggest the possibility that TNFα and IL-17A could elevate the depressive symptoms of men.

Electrochemiluminescence immunoassay system based on PCN-224-Mn and gold-platinum bimetallic nanoflowers for sensitive detection of ochratoxin A

In this work, a novel Electrochemiluminescence Immunosensor was constructed using PCN-224-Mn and gold-platinum nanoflowers (AuPt NFs) for the ultrasensitive detection of ochratoxin A (OTA). PCN-224 modified with Mn (II) was synthesized as a probe material. The interaction efficiency of PCN-224 with S2O82− was also greatly improved. AuPt NFs were used as the substrate material for the electrodes. It has favorable biocompatibility, large specific surface area and can bind more antigen. Also greatly increased the electroactive surface area and conductivity of the electrode. OTA was detected using a competitive immunoassay strategy, in which OTA in the sample competes with the encapsulated antigen for a finite number of antibodies. ECLIA for the detection of OTA was designed to be highly sensitive, with a linear range from 0.0002 ng mL−1 to 1000 ng mL−1 and a LOD as low as 0.067 pg mL−1. In addition, it was evident from the electrochemical analyses that PCN-224-Mn had a stronger and more stable ECL signal compared to the plain PCN-224. The successful preparation of specific, sensitive and reproducible ECL immunosensors confirms the great promise for the detection of OTA or other small molecule mycotoxins.

Establishment of IGF-1 and IGFBP-3 continuous reference percentiles from data of healthy children using three kinds of immunoassay systems

Background and aimsAppropriate continuous reference intervals (RIs) for serum insulin-like growth factor 1 (IGF-1) and insulin-like growth factor-binding protein 3 (IGFBP-3) are important for diagnosing growth hormone deficiency or excess. Material and methodsWe retrospectively reviewed serum IGF-1 and IGFBP-3 levels in Korean children aged 0–17 years who were diagnosed as healthy during a short stature workup in the outpatient clinics of three hospitals. IGF-1 and IGFBP-3 levels were measured using various immunoassays, including Liaison XL for IGF-1, an immunoradiometric assay (IRMA) for IGFBP-3 (n = 5522), and Immulite 2000 (n = 3036) and cobas e801 (n = 314). We established RIs from the 2.5th to 97.5th percentile RI curves using the lambda–mu–sigma (LMS) method for each sex group. ResultsPediatric serum continuous IGF-1 and IGFBP-3 reference percentiles by LMS method were found to be immunoassay method-dependent, but aligned relatively well with the manufacturers’ RIs. IGFBP-3 levels displayed notable discrepancies among the different immunoassay methods. ConclusionAge- and sex-specific pediatric LMS based continuous reference intervals are method dependent and they should be calculated for dynamic parameters that show variations throughout childhood.

Association between serum neurofilament light chains and depression: A cross-sectional study based on NHANES 2013–2014 database

BackgroundSerum neurofilament light chain (sNfl), identified as a promising biomarker, is a protein released into the bloodstream post-axonal damage. Studies on its correlation with depression, however, remains scarce. The purpose of this study was to investigate the potential relationship between sNfL levels and risk of depression among a representative segment of the U. S. populace. MethodsThis study included 1,909 participants from the 2013-2014 National Health and Nutrition Examination Survey. The 9-item Patient Health Questionnaire (PHQ-9 scale) assessed depression symptoms, while sNfl concentrations were measured using the Attelica fully automated immunoassay system. The logistic regression, restricted cubic splines (RCS), and subgroup analysis were performed to assess the relationship between sNfL, lnsNfL (log-transformed values of sNfl), and depression. ResultsAfter adjusting for sociodemographic variables, lifestyle, and chronic conditions, sNfl and lnsNfL levels positively correlated with depression. A unit increase in sNfL and lnsNfL levels was linked to a 0.7 % and 33.8 % rise in depression risk, respectively [OR (95 % CI): 1.007 (1.000, 1.014), p = 0.041 for sNfl; 1.338 (1.015, 1.764), p = 0.039 for lnsNfl]. Additionally, a positive linear association was observed between lnsNfl levels and the risk of depression (p for overall = 0.039, p for nonlinear = 0.189 in RCS). No significant differences were observed across subgroups between lnsNfl and depression, with no significant impact on this relationship from subgroups (All p for interaction >0.05). ConclusionThe findings of our study suggest a significant positive correlation between sNfl and depression, warranting further investigation into the molecular dynamics linking sNfL to depression and subgroup variability.

A Novel High-Throughput and Sensitive Electrochemiluminescence Immunoassay System.

(1) Background: In vitro diagnostic (IVD) tests are the main means of obtaining diagnostic information for clinical purposes. The electrochemiluminescence immunoassay (ECLIA) has become an important in vitro diagnostic technique. It has unique advantages and broad market prospects due to its sensitivity, detection limit, detection range and reagent stability. At present, there is a need to develop and optimize electrochemiluminescence immunoassay subsystems to achieve high-throughput outputs and accurate detection of instruments to promote their clinical application. (2) Methods: On the basis of the demand for clinical testing instruments with high detection accuracy and speed, this study constructed an electrochemiluminescence immunoassay system by designing magnetic separation modules, introducing PMT and optimizing the system timing regulation capability. (3) Results: The magnetic separation modules can increase the detection accuracy, the PMT system increases the detection sensitivity and optimized system timing can achieve maximum test output. Furthermore, this system performs well in terms of its linearity, detection limit, signal-to-noise ratio, precision and accuracy. (4) Conclusions: The electrochemiluminescence immunoassay system is capable of high throughput with good sensitivity and accuracy, meeting the basic requirements of clinical applications for detection capacity and output throughput.

Assessment of Thyroid Profile in Patients with Hepatitis C Virus Infection

Background: Hepatitis C virus (HCV) infection remains a major public health concern in Pakistan, with potential impacts on thyroid function. Long-term HCV infection has been associated with thyroid dysfunction, but the extent of this relationship is not fully understood.Objective: This study aimed to evaluate the thyroid hormone profile in HCV-positive patients to assess the prevalence of thyroid dysfunction in this population.Methods: A cross-sectional study was conducted on 120 HCV-positive patients aged 18-70 years. Patients with liver cirrhosis, known thyroid disorders, or medications affecting thyroid function were excluded. Blood samples were collected, and thyroid hormones (TSH, FT3, FT4) were measured using an automated immunoassay system. Data were analyzed using SPSS version 25.0, with a p-value &lt;0.05 considered statistically significant.Results: The study found that 17.50% of patients had elevated TSH levels, while 11.66% and 10.83% had elevated FT3 and FT4 levels, respectively. The mean values for TSH, FT3, and FT4 were 1.15 ± 0.515 µIU/mL, 1.10 ± 0.351 pg/mL, and 1.12 ± 0.361 ng/dL.Conclusion: The study demonstrated a significant association between HCV infection and thyroid dysfunction, highlighting the need for regular thyroid function monitoring in HCV-positive patients.

Janus-Type Immunofluorescent Probes and a Quantitative Immunoassay System.

To realize highly sensitive immunoassays, high optical density probes conjugated with antibodies for target antigens have been demanded in order to increase the visibility of antigen-antibody complex formation. We herein demonstrate the development of an immunoassay system using magnetic and fluorescent Janus particles as probes in conjunction with an antibody-immobilized microfluidic device. The concentration of the detection limit at which there was a significant difference between SARS-CoV-2 and human coronavirus 229E antigens was 3.1 ng/mL, and the standard deviation of the signal was less than 5%. The immunofluorescent probe and immunoassay system developed in this study are expected to be applicable not only to SARS-CoV-2 but also to the quantitative measurement of various other disease marker proteins and biomolecules.

Pediatric reference values of NT-proBNP and Galectin-3 based on a French cohort

BackgroundIn pediatric cardiology, the fact that some new biomarkers have assay-specific normal values has to be considered for correct clinical decisions. The current study aimed to provide age-adjusted normative values for NT-proBNP and Galectin-3 using the Abbott immunoassay system from a prospective French pediatric cohort sera collection and to validate our data for NT-proBNP on a second retrospective cohort. MethodsWe analyzed 283 consecutive samples for NT-proBNP and 140 samples for Galectin-3 collected from apparently healthy children (0–18 years) with outpatient treatment at our institution (Hôpital Necker-Enfants malades, Paris, France) during 24 months. ResultsFor NT-proBNP and Galectin-3, we establish four age partitions, respectively two (<2 years / >2 years) and establish upper reference values and their 90 % CI for each biomarker (Galectin-3 (ng/mL): 56 [44–70] / 26 [23–29]). We evaluated the diagnostic performance of our upper reference values of NT-proBNP on a retrospective cohort (n = 428) with positive predictive value of 0.92. ConclusionsUsing Abbott immunoassay system, we report age-specific reference values for NT-proBNP and for the first time for Galectin-3 in a healthy French pediatric cohort. These data call for larger cohort studies to define more robustly percentiles and diagnostic performance for NT-proBNP.

An automated magnetic beads-based chemiluminescence immunoassay system for simultaneous quantification of multi-mycotoxins in agricultural products

The coexistence of multiple mycotoxins poses a significant risk to the safety of agricultural products. Hence, a novel and automated magnetic beads-based chemiluminescence immunoassay (MCLIA) system was developed for the simultaneous quantification of typical multi-mycotoxins, including zearalenone (ZEN), Ochratoxin A (OTA), deoxynivalenol (DON), and aflatoxin B1 (AFB1). It comprises a compact chemiluminescence-based analyzer and a specially designed mycotoxin assay kit. Firstly, antimycotoxin monoclonal antibody (mAb) was coupled with alkaline phosphatase (AP), and the antigen of mycotoxin was then with biotin. After detailed optimization of this indirect competition immunoassay, all necessary reagents were preloaded and sealed into a specialized plastic reagent strip to prepare the assay kit. Secondly, a compact chemiluminescence-based analyzer was developed by programmatically integrating magnetic, thermal, and optical mechanisms. The MCLIA system facilitates the detection of mycotoxins in up to 8 samples simultaneously or various mycotoxins in different samples within 20 min, according to actual needs. The detection limits (LOD) for ZEN, OTA, DON, and AFB1 were 2.55, 0.64, 15.47, and 0.78 μg/kg, respectively, with the 50 % inhibition concentrations (IC50) in the ranges of 1.84−4.25, 0.95−1.69, 11.36−13.98, and 0.37−0.54 ng/mL. Parallel analysis of commercial agricultural products demonstrated a strong linear correlation (R2 = 0.9843–0.9962) with UPLC-HRMS, confirming the MCLIA system's reliability for the simultaneous quantitative detection of various mycotoxins. Offering advantages in detection sensitivity, dynamic range, and turnaround time, the compact MCLIA system facilitates automated and parallelized detection in the model of “sample-in to result-out”. It presents a versatile platform for the efficient immunodetection of other contaminants.

Cerebrospinal Fluid Cytokine and Chemokine Profiles in Central Nervous System Sarcoidosis: Diagnostic and Immunopathologic Insights.

To evaluate the cerebrospinal fluid (CSF) cytokine/chemokine profile of central nervous system (CNS) neurosarcoidosis (NS), and its utility in differential diagnosis, treatment, and prognostication. In this case-control study, we validated 17 cytokines/chemokines (interleukin [IL]-1-beta, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-13, IL-17A, BAFF, IL-8/CXCL8, CXCL9, CXCL10, CXCL13, GM-CSF, interferon-gamma, and tumor necrosis factor [TNF]-alpha) in a multiplexed automated immunoassay system (ELLA; Bio-Techne, Minneapolis, MN, USA), and assessed them in CSF and serum of symptomatic patients with probable or definite CNS NS (01/2011-02/2023) with gadolinium enhancement and/or CSF pleocytosis. Patients with multiple sclerosis, primary CNS lymphoma, aquaporin-4 immunoglobulin G positivity, non-inflammatory disorders, and healthy individuals were used as controls. A total of 32 NS patients (59% women; median age, 59 years [19-81]) were included; concurrent sera were available in 12. CSF controls consisted of 26 multiple sclerosis, 8 primary CNS lymphoma, 84 aquaporin-4 immunoglobulin G positive, and 34 patients with non-inflammatory disorders. Gadolinium enhancement was present in 31 of 32 NS patients, and CSF pleocytosis in 27 of 32 (84%). CSF IL-2, IL-6, IL-10, IL-13, BAFF, IL-8/CXCL8, CXCL9, CXCL10, CXCL13, GM-CSF, interferon-gamma, and TNF-alpha levels were significantly higher in NS patients compared with non-inflammatory controls (p ≤ 0.02); elevations were more common in CSF than serum. Concurrent elevation of IL-6, CXCL9, CXCL10, GM-CSF, interferon-gamma, and TNF-alpha was present in 18 of 32 NS patients, but only in 1 control. Elevated IL-6, IL-10, IL-13, CXCL9, CXL10, GM-CSF, and TNF-alpha associated with measures of disease activity. NS CSF cytokine/chemokine profiles suggest T cell (mainly T helper cell type 1), macrophage, and B-cell involvement. These signatures aid in NS diagnosis, indicate disease activity, and suggest therapeutic avenues. ANN NEUROL 2024.