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Keywords = CLIA immunoassays

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25 pages, 340 KB  
Review
Measuring Humoral Immune Responses to SARS-CoV-2: A Comprehensive Review of Serological Assays
by Huijing Xue, Katarzyna Haynesworth, Heidi A. Hempel, Troy J. Kemp and Ligia A. Pinto
Vaccines 2026, 14(5), 395; https://doi.org/10.3390/vaccines14050395 - 28 Apr 2026
Viewed by 541
Abstract
The COVID-19 pandemic highlighted the critical role of serological assays in understanding antiviral immune responses, monitoring vaccine efficacy, and informing public health strategies. This review provides a comprehensive overview of commonly used SARS-CoV-2 antibody detection methods, focusing on binding and neutralization assays. Antibody [...] Read more.
The COVID-19 pandemic highlighted the critical role of serological assays in understanding antiviral immune responses, monitoring vaccine efficacy, and informing public health strategies. This review provides a comprehensive overview of commonly used SARS-CoV-2 antibody detection methods, focusing on binding and neutralization assays. Antibody binding assays, including enzyme-linked immunosorbent assays (ELISAs), chemiluminescence immunoassays (CLIAs), lateral flow immunoassays (LFAs), and multiplex platforms, enable the rapid and high-throughput detection of immunoglobulin isotypes against various viral antigens. Neutralization assays, including live-virus, pseudovirus (PsV), and surrogate assays, offer functional insights into the ability of antibodies to prevent viral entry, though they often require higher biosafety levels and optimization. Serological assays, primarily antibody binding assays and several surrogate neutralization assays, received Emergency Use Authorization (EUA) during the pandemic, supporting seroprevalence efforts. Antibody binding assays and neutralization assays were also widely used in vaccine immunogenicity studies. Despite many standardization initiatives, assay standardization and data harmonization remain challenging and require further efforts. The choice of assay should be guided by study goals: antibody binding assays are preferred for high-throughput monitoring and epidemiological studies, while neutralization assays are essential for assessing functional immunity and variant-specific neutralization and protection. Full article
(This article belongs to the Special Issue Vaccines and Antibody-Based Therapeutics Against Infectious Disease)
14 pages, 864 KB  
Article
The First Selective Screening for Type 1 Diabetes in a Pediatric Population in Bulgaria
by Natasha Yaneva, Meri Petrova, Adelina Yordanova, Trifon Popov, Margarita Arshinkova, Dobroslav Kyurkchiev and Ekaterina Kurteva
J. Clin. Med. 2026, 15(8), 3075; https://doi.org/10.3390/jcm15083075 - 17 Apr 2026
Viewed by 617
Abstract
Background: Screening for presymptomatic type 1 diabetes (T1D) reduces the risk of diabetic ketoacidosis (DKA) and allows for early intervention with disease-modifying therapies. Despite the rising incidence of T1D in Bulgaria, screening initiatives remain limited. This pilot study aims to evaluate the feasibility [...] Read more.
Background: Screening for presymptomatic type 1 diabetes (T1D) reduces the risk of diabetic ketoacidosis (DKA) and allows for early intervention with disease-modifying therapies. Despite the rising incidence of T1D in Bulgaria, screening initiatives remain limited. This pilot study aims to evaluate the feasibility of selective T1D screening in high-risk children and identify potential clinical associations with islet autoimmunity. Methods: The study targeted a recruitment of 250 children aged 0–18 years (200 with a relative with T1D and 50 without). Screening for islet autoantibodies (AABs), including glutamic acid decarboxylase (GADA), insulin (IAA), insulinoma-associated-2 (IA-2A), zinc transporter-8 (ZnT8A), and islet cell cytoplasmic autoantibodies (ICAs), was performed via chemiluminescence immunoassay (CLIA). Participants testing positive for one or more AABs were scheduled for longitudinal immunological and metabolic follow-up to evaluate the persistence of autoimmunity and disease progression. Results: Between October 2024 and February 2026, the pilot study recruited 210 participants (84% of the 250 target), including 160 children with a relative (target 200) and 50 without a family history of T1D (target 50). Within the high-risk group, seven children (4.4%) tested positive for a single autoantibody (3 GADA, 2 ZnT8A, 1 IA-2A, and 1 IAA), while no autoantibodies were detected in the group without a relative. No cases of multiple autoantibody positivity or stage 3 T1D were identified in either group. Furthermore, no statistically significant associations were observed between autoantibody positivity and secondary factors, including breastfeeding, allergic status, a high-glycemic diet, frequent illness, and personal history of autoimmune disease. Conclusions: The findings validate the feasibility of selective T1D screening in Bulgaria, driven by high public interest and successful recruitment across both high-risk and general population cohorts. While this exploratory study found no significant clinical correlations, it establishes a vital roadmap for larger, longitudinal research. Ultimately, this pilot framework provides a scalable model for implementing standardized early detection to reduce the burden of T1D on the national healthcare system. Full article
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22 pages, 2263 KB  
Article
Acridinium Chemiluminogenic Labels—Synthesis, Analytical Performance, and Mechanism of Light Generation—A Comparison in View of Biomedical Diagnostics
by Karol Krzymiński, Beata Zadykowicz, Justyna Czechowska, Paweł Rudnicki-Velasquez, Illia Serdiuk, Adam K. Sieradzan and Lucyna Holec-Gąsior
Molecules 2026, 31(6), 1041; https://doi.org/10.3390/molecules31061041 - 20 Mar 2026
Viewed by 646
Abstract
This paper presents the synthesis, physicochemical characterisation, and analytical applications of chemiluminescent (CL) labels based on acridinium salts (ALs) for biomedical diagnostics. These compounds emit light as a result of oxidative reactions and represent an established class of reagents widely employed in chemiluminescence [...] Read more.
This paper presents the synthesis, physicochemical characterisation, and analytical applications of chemiluminescent (CL) labels based on acridinium salts (ALs) for biomedical diagnostics. These compounds emit light as a result of oxidative reactions and represent an established class of reagents widely employed in chemiluminescence immunochemical assays (CLIAs) today. A series of structurally differentiated acridinium labels (AL1AL5) was synthesised applying mostly original synthetic routes and purified to chromatographic purity (>90%, RP-HPLC). The compounds, including a commercial product treated as a reference, were successfully conjugated to anti-human IgG, yielding stable immunochemical reagents suitable for immunoassays with CL detection. The chemiluminescence properties of the obtained labels and their protein conjugates were investigated in aqueous buffers and in the presence of surfactants. The emission profiles exhibited characteristic flash-type kinetics with emission maxima occurring within 0.15–0.25 s after reaction initiation. The presence of surfactants more or less significantly enhanced the emission intensity, with signal increases of up to approx. 2-fold compared to surfactant-free systems. Analytical calibration demonstrated a linear response of signal derived from native labels over at least one order of magnitude of concentration, with detection limits falling in the range of 10−9–10−10 M, confirming the high sensitivity of the developed compounds. The experimental results were supported by theoretical studies using density functional theory (DFT), which confirmed the energetic feasibility of the CL reaction pathway and identified structural factors influencing activation barriers. Additional semiempirical calculations (PM7) indicated that the dielectric environment and proximity of ionic species can influence the reaction energetics, providing mechanistic support for the experimentally observed effects of surfactants. The results demonstrate that both molecular structure and microenvironment influence CL efficiency and kinetics of the investigated systems. The developed acridinium labels exhibit analytical performance better or comparable to commercial reagents and are fully compatible with standard immunodiagnostic conjugation protocols, confirming their suitability for use in modern chemiluminescent immunoassays. Full article
(This article belongs to the Special Issue Chemiluminescence and Photoluminescence of Advanced Compounds)
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8 pages, 466 KB  
Article
Comparative IgG-IgM Western Blot in the Diagnosis of Congenital Toxoplasmosis: A Valid Diagnostic Tool
by Alice Bonetti, Ambra Vola, Daniele Lilleri, Lucrezia Lo Grasso, Milena Furione, Alessia Arossa, Alessandra Ricciardi, Claudia Viganò, Alessia Bressan, Claudia Pavia, Annalisa De Silvestri, Giulia Gambini, Fausto Baldanti and Valeria Meroni
Pathogens 2026, 15(2), 225; https://doi.org/10.3390/pathogens15020225 - 17 Feb 2026
Viewed by 824
Abstract
Congenital toxoplasmosis (CT) results from vertical transmission of Toxoplasma gondii during maternal infection in pregnancy. Early diagnosis in newborns is crucial to initiate timely therapy and prevent long-term sequelae. The IgM Immunosorbent Agglutination Assay (ISAGA) has historically been considered an important diagnostic tool [...] Read more.
Congenital toxoplasmosis (CT) results from vertical transmission of Toxoplasma gondii during maternal infection in pregnancy. Early diagnosis in newborns is crucial to initiate timely therapy and prevent long-term sequelae. The IgM Immunosorbent Agglutination Assay (ISAGA) has historically been considered an important diagnostic tool for CT; however, its recent market withdrawal necessitates alternative approaches. We conducted a retrospective observational study at Fondazione IRCCS Policlinico San Matteo, Pavia, Italy, including 44 newborns born to mothers with confirmed toxoplasmosis between 2019 and 2022. Newborns were classified as CT (n = 19) or non-CT (n = 25) based on serological follow-up, comparative Western blot (CWB) and Interferon Gamma Release Assay (IGRA). Sensitivity and specificity of CWB, IgM Chemiluminescent Immunoassay (CLIA), and IgM ISAGA were assessed at birth and at one month. At birth, CWB demonstrated 88.9% sensitivity, significantly higher than IgM CLIA (52.6%) and IgM ISAGA (57.9%). Specificity was 100% at birth and 92% at one month. CWB retained high sensitivity at one month (81.8%). IGRA complemented CWB in confirming or excluding infection in cases with equivocal or false-negative serology. Comparative Western blot thus represents a robust diagnostic alternative for CT, ensuring early detection and timely treatment, particularly in the absence of IgM ISAGA. Full article
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10 pages, 886 KB  
Article
Evaluation of Commercial Immunoassays for Rubella Virus IgG Detection in Low-Antibody Sera Using a Recombinant Immunoblot as a Reference Method
by Carmen Ortega, Antonio Sampedro-Padilla, Pablo Mazuelas, Jose Serrano, Ana Abreu, Juan Antonio Reguera, Javier Rodríguez-Granger, Fernando Cobo, Juan Francisco Gutiérrez-Bautista and Antonio Sampedro
Microorganisms 2026, 14(1), 58; https://doi.org/10.3390/microorganisms14010058 - 26 Dec 2025
Viewed by 921
Abstract
Rubella virus (RV) IgG quantification is essential for verifying immunity, particularly in prenatal care. However, substantial variability exists among commercial immunoassays, especially when testing low-antibody sera. In this study, we evaluated five commercial assays—four chemiluminescent immunoassays (CLIAs) and one Enzyme-linked Immunosorbent Assay (ELISA)—using [...] Read more.
Rubella virus (RV) IgG quantification is essential for verifying immunity, particularly in prenatal care. However, substantial variability exists among commercial immunoassays, especially when testing low-antibody sera. In this study, we evaluated five commercial assays—four chemiluminescent immunoassays (CLIAs) and one Enzyme-linked Immunosorbent Assay (ELISA)—using a recombinant immunoblot (IB) as the reference method. A panel of 137 serum samples with low or undetectable IgG levels was analyzed. Sensitivity ranged from 19.6% to 70.1%, while specificity exceeded 94%. Only 18.6% of immunoblot-positive samples tested positive across all assays. Marked quantitative differences were observed, with the Atellica assay yielding the highest titers and Alinity the lowest. Reclassifying equivocal results as positive improved concordance without compromising specificity. These findings suggest that current cut-off values, derived from post-infection sera, may be inadequate for vaccinated populations. A single universal threshold may lead to misclassification and underestimation of immunity. Harmonization of assay calibrations, antigenic targets, and interpretation criteria is urgently needed to ensure reliable rubella immunity assessments in clinical and public health settings. Full article
(This article belongs to the Section Medical Microbiology)
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15 pages, 1984 KB  
Article
Evaluation of Adiponectin as a Metabolic Risk Indicator in the Panamanian Population
by Orlando Serrano Garrido, Xenia Hernandez Adames, Ivonne Torres-Atencio, Ana Espinosa De Ycaza, Maria Fabiana Piran Arce, Ana Tejada Espinosa and Griselda Arteaga
Obesities 2025, 5(4), 81; https://doi.org/10.3390/obesities5040081 - 14 Nov 2025
Cited by 1 | Viewed by 1490
Abstract
Adiponectin, an adipokine secreted by adipocytes with anti-inflammatory and insulin-sensitizing properties, circulates in several isoforms, of which total and high-molecular-weight (HMW) adiponectin are the most physiologically relevant. While adiponectin has been inversely associated with obesity and metabolic syndrome (MetS), evidence from Latin American [...] Read more.
Adiponectin, an adipokine secreted by adipocytes with anti-inflammatory and insulin-sensitizing properties, circulates in several isoforms, of which total and high-molecular-weight (HMW) adiponectin are the most physiologically relevant. While adiponectin has been inversely associated with obesity and metabolic syndrome (MetS), evidence from Latin American populations remains scarce. To explore its role in this context, we conducted a case–control study in 310 Panamanian adults, including 77 individuals with MetS and 233 controls, diagnosed according to the Latin American Diabetes Association (ALAD) criteria. Serum adiponectin, lipid profile, glucose, HbA1c, and body composition were evaluated, with adiponectin quantified by chemiluminescent immunoassay (CLIA). Correlations with metabolic parameters were analyzed using GraphPad Prism 10.5. Participants with MetS exhibited significantly lower adiponectin concentrations compared with controls (7.75 ± 2.58 µg/mL vs. 9.53 ± 3.31 µg/mL, p = 0.0030). Adiponectin levels were significantly lower in males than in females (p = 0.0083) and showed inverse correlations with visceral fat (r = −0.26, p < 0.001), triglycerides (r = −0.25, p = 0.0062), insulin (r = −0.31, p < 0.0001), and HbA1c (r = −0.11, p = 0.046). Conversely, a positive association was observed with HDL cholesterol (r = 0.37, p < 0.0001). Individuals with HbA1c ≥ 6.5% or insulin ≥ 15 µU/mL exhibited markedly reduced adiponectin concentrations (p = 0.0006 and p < 0.0001, respectively). The ROC analysis yielded an AUC of 0.69, indicating a moderate discriminatory ability of adiponectin for identifying MetS in this population. These findings confirm that adiponectin is inversely associated with several metabolic risk factors, supporting its potential utility as a biomarker for early detection and risk stratification of metabolic syndrome in the Panamanian population. Full article
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24 pages, 1219 KB  
Review
Advances in Point-of-Care Infectious Disease Diagnostics: Integration of Technologies, Validation, Artificial Intelligence, and Regulatory Oversight
by Moustafa Kardjadj
Diagnostics 2025, 15(22), 2845; https://doi.org/10.3390/diagnostics15222845 - 10 Nov 2025
Cited by 23 | Viewed by 7273
Abstract
Point-of-care (POC) infectious disease diagnostics are reshaping global health by delivering rapid, decentralized, and clinically actionable results that link bedside testing to population-level surveillance. Valued at approximately USD 53 billion in 2024 and projected to nearly double by 2033, the global POC diagnostics [...] Read more.
Point-of-care (POC) infectious disease diagnostics are reshaping global health by delivering rapid, decentralized, and clinically actionable results that link bedside testing to population-level surveillance. Valued at approximately USD 53 billion in 2024 and projected to nearly double by 2033, the global POC diagnostics market is driven by infectious disease assays and accelerated by innovations in molecular amplification, biosensors, microfluidics, and artificial intelligence (AI). This review integrates current evidence across technological, clinical, regulatory, and public health domains. Immunoassays remain the backbone of volume deployment, while molecular nucleic acid amplification tests (NAATs) and emerging CRISPR-based platforms achieve laboratory-grade sensitivity at the point of care. AI has transitioned from an experimental tool to an embedded analytical layer that enhances image interpretation, multiplex signal deconvolution, and automated quality control. Rigorous validation, including analytical accuracy, clinical performance in intended-use settings, and usability testing under CLIA guidance, remains central to ensuring reliability in decentralized environments. Regulatory frameworks are adapting in parallel: FDA’s lifecycle oversight of AI-enabled devices, the European IVDR’s expanded evidence requirements, and the WHO Prequalification all emphasize continuous post-market surveillance. From a public health perspective, POC diagnostics have improved early case detection, treatment initiation, and outbreak containment for HIV, tuberculosis, malaria, influenza, RSV, and COVID-19. Yet persistent challenges (including limited harmonization of standards, uneven reimbursement, and scarce real-world data from low- and middle-income countries) continue to constrain equitable adoption. POC infectious disease diagnostics are thus entering a pivotal phase of digitization and regulatory maturity. Addressing remaining gaps in validation, lifecycle monitoring, and implementation equity will determine whether these technologies achieve their full promise as clinical accelerators and as cornerstones of global infectious disease preparedness. Full article
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23 pages, 2318 KB  
Article
Validation of the i-Tracker Drug and Total Anti-Drug Antibody CLIA Assays on IDS-iSYS for Therapeutic Drug Monitoring in Adalimumab- and Infliximab-Treated Patients
by Akpedje Serena Dossou, Serena Kang, Tahira Kalhoro, Eduardo Castro-Echeverry and Nathan C. Horton
Diagnostics 2025, 15(19), 2447; https://doi.org/10.3390/diagnostics15192447 - 25 Sep 2025
Cited by 2 | Viewed by 1749
Abstract
Background/Objectives: Adalimumab and Infliximab are biologics used to treat autoimmune diseases. Monitoring drug and anti-drug antibody (ADA) levels in patients helps optimize treatment. However, current quantitation methodologies for drug and total (free and drug-bound) ADAs often involve multi-step workflows. Automated systems can [...] Read more.
Background/Objectives: Adalimumab and Infliximab are biologics used to treat autoimmune diseases. Monitoring drug and anti-drug antibody (ADA) levels in patients helps optimize treatment. However, current quantitation methodologies for drug and total (free and drug-bound) ADAs often involve multi-step workflows. Automated systems can streamline the process. The i-Tracker chemiluminescent immunoassays (CLIA) are cartridge-based kits for quantifying serum levels of drugs such as Adalimumab, Infliximab, and associated ADAs. Herein, we aimed to establish performance characteristics of the i-Tracker Adalimumab, Infliximab, and total ADAs in serum on the random-access analyzer IDS-iSYS and to compare patient results with an electrochemiluminescent immunoassay (ECLIA)-based reference method. Methods: Remnant serum specimens, calibration material, or spiked serum were used to evaluate assay linearity, precision, functional sensitivity, and accuracy on the IDS-iSYS analyzer and to perform the method comparison. Results: The assays displayed linearity, accuracy, and up to 8% imprecision across clinically relevant analyte ranges. Compared to the reference method, the drug assays exhibited a strong linear fit (correlation coefficient > 0.95) with <±1.0 µg/mL mean bias. The total anti-Adalimumab assay demonstrated over 85% qualitative agreement. The total anti-Infliximab assay, however, showed higher detection rate of ADAs in Infliximab-treated patient specimens, yielding < 60% negative agreement with the reference method. Although i-Tracker total ADA assays exhibited drug sensitivity, they still detected ADAs in supratherapeutic drug concentrations. Conclusions: The i-Tracker assays demonstrated robust analytical performance, suggesting potential for clinical application. The method comparison underscored functional differences with the reference method, an important consideration when transitioning assay formats for monitoring Adalimumab- and Infliximab-treated patients. Full article
(This article belongs to the Special Issue Advances in the Laboratory Diagnosis)
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12 pages, 716 KB  
Article
Development of a Chemiluminescence Immunoassay for the Serological Diagnosis of Sheep and Bovine Brucellosis
by Xin Yan, Mingze Chen, Yuning Liu, Mingjun Sun, Mengkun Huang, Jihui Jin, Jiaqi Li, Xiangxiang Sun, Mengda Liu, Haobo Zhang, Weixing Shao, Shufang Sun, Xiaoxu Fan and Wenlong Nan
Microorganisms 2025, 13(9), 2214; https://doi.org/10.3390/microorganisms13092214 - 22 Sep 2025
Cited by 1 | Viewed by 1923
Abstract
Brucellosis, a zoonotic infection caused by the intracellular pathogen Brucella, leads to chronic multi-organ damage. Currently, rapid, accurate, and sensitive diagnostic technologies are crucial for the prevention and control of brucellosis. This study describes the development of a chemiluminescent immunoassay (Bru-CLIA) for [...] Read more.
Brucellosis, a zoonotic infection caused by the intracellular pathogen Brucella, leads to chronic multi-organ damage. Currently, rapid, accurate, and sensitive diagnostic technologies are crucial for the prevention and control of brucellosis. This study describes the development of a chemiluminescent immunoassay (Bru-CLIA) for sheep and bovine brucellosis antibody detection, utilizing Brucella abortus strain A19 lipopolysaccharide-coated magnetic particles (LPS-MPs) as the serum antigen and acridinium ester-labeled recombinant streptococcal protein G (AE-SPG) for signal generation. After optimizing the assay’s parameters, the Bru-CLIA demonstrated a sensitivity of approximately 1 IU/mL and 2 IU/mL for detecting sheep and bovine brucellosis, respectively. No cross-reactivity was observed with sera from animals immunized with Escherichia coli O157:H7, Mycobacterium tuberculosis, Vibrio cholerae, Legionella, Salmonella, Foot and Mouth Disease virus types O and A, Bovine viral diarrhea virus, Sheep contagious pleuropneumonia, Goat pox virus, or Peste des Petits Ruminants virus, indicating strong specificity. The testing of 81 sheep serum samples and 96 bovine serum samples revealed that Bru-CLIA showed 87.65% and 93.75% concordance with the ID-VET commercial kits for sheep and bovine brucellosis detection, respectively. These results demonstrate that Bru-CLIA offers high specificity, sensitivity, repeatability, and reliability, making it a viable rapid diagnostic tool for the epidemiological surveillance of brucellosis. Full article
(This article belongs to the Section Veterinary Microbiology)
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11 pages, 723 KB  
Article
The Anti-Nucleocapsid IgG Antibody as a Marker of SARS-CoV-2 Infection for Hemodialysis Patients
by Akemi Hara, Shun Watanabe, Toyoaki Sawano, Yuki Sonoda, Hiroaki Saito, Akihiko Ozaki, Masatoshi Wakui, Tianchen Zhao, Chika Yamamoto, Yurie Kobashi, Toshiki Abe, Takeshi Kawamura, Akira Sugiyama, Aya Nakayama, Yudai Kaneko, Hiroaki Shimmura and Masaharu Tsubokura
Vaccines 2025, 13(7), 750; https://doi.org/10.3390/vaccines13070750 - 13 Jul 2025
Viewed by 1433
Abstract
Background: Hemodialysis patients, due to impaired kidney function and compromised immune responses, face increased risks from SARS-CoV-2. Anti-nucleocapsid IgG (anti-IgG N) antibodies are a commonly used marker to assess prior infection in the general population; however, their efficacy for hemodialysis patients remains unclear. [...] Read more.
Background: Hemodialysis patients, due to impaired kidney function and compromised immune responses, face increased risks from SARS-CoV-2. Anti-nucleocapsid IgG (anti-IgG N) antibodies are a commonly used marker to assess prior infection in the general population; however, their efficacy for hemodialysis patients remains unclear. Methods: A retrospective study of 361 hemodialysis patients evaluated anti-IgG N antibodies for detecting prior SARS-CoV-2 infection. Antibody levels were measured using a chemiluminescence immunoassay (CLIA) over the four time points. Boxplots illustrated antibody distribution across sampling stages and infection status. Logistic regression and receiver operating characteristic (ROC) curve analysis determined diagnostic accuracy, sensitivity, specificity, and optimal cutoff values. Results: Among the 361 hemodialysis patients, 36 (10.0%) had SARS-CoV-2 infection. Sex distribution showed a trend toward significance (p = 0.05). Boxplot analysis showed that anti-IgG N levels remained low in non-infected patients but increased in infected patients, peaking at the third sampling. Anti-IgG N demonstrated high diagnostic accuracy (AUC: 0.973–0.865) but declined over time (p = 0.00525). The optimal cutoff at C1 was 0.01 AU/mL (sensitivity 1.00, specificity 0.94). Adjusted models had lower predictive value. Conclusions: Anti-IgG N antibodies showed high diagnostic accuracy for detecting prior SARS-CoV-2 infection in hemodialysis patients, though performance declined over time. These findings highlight the need for tailored diagnostic strategies in this vulnerable population. Full article
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9 pages, 764 KB  
Article
A Comparative Evaluation of the Chemiluminescence Immunoassay and ELISA for the Detection of Islet Autoantibodies in Type 1 Diabetes
by Elisa Danese, Claudia Piona, Mariateresa Rizza, Elena Tiziani, Laura Pighi, Elisa Morotti, Gian Luca Salvagno, Camilla Mattiuzzi, Claudio Maffeis and Giuseppe Lippi
Diagnostics 2025, 15(13), 1695; https://doi.org/10.3390/diagnostics15131695 - 3 Jul 2025
Cited by 4 | Viewed by 4214
Abstract
Background: The early detection of type 1 diabetes (T1D) through screening for major islet autoantibodies is receiving increasing attention as a public health strategy, exemplified by the recent implementation of a pilot pediatric screening program in Italy. The transition from research-based screening to [...] Read more.
Background: The early detection of type 1 diabetes (T1D) through screening for major islet autoantibodies is receiving increasing attention as a public health strategy, exemplified by the recent implementation of a pilot pediatric screening program in Italy. The transition from research-based screening to large-scale population initiatives needs automated and standardized assays that are capable of processing extensive sample volumes. Hence, this study aimed to evaluate the analytical performance and comparability of a fully automated chemiluminescence immunoassay (CLIA) compared to a conventional enzyme-linked immunosorbent assay (ELISA) for the detection of three classes of major islet antibodies—anti-GAD (GADA), anti-IA-2 (IA-2A), and anti-ZnT8 (ZnT8A). Methods: A total of 104 serum specimens were analyzed for each autoantibody using both ELISA (RSR and Medyzim, DYNES, DSX) and CLIA (MAGLUMI 800). Assay precision and linearity were assessed through intra-assay variability studies and dilution protocols. Methods agreement was evaluated with Passing–Bablok regression, Spearman’s correlation, Bland–Altman analysis, and Cohen’s kappa statistics. Results: The CLIA showed good precision and excellent linearity across clinically relevant concentration ranges of all islet antibodies. Correlation coefficients and categorical agreement between CLIA and ELISA were high (r > 0.96 and Cohen’s kappa >0.8 for all), with ZnT8A exhibiting the highest concordance. However, proportional biases were found, as CLIA systematically underestimated GADA and ZnT8A levels, while overestimated IA-2A compared to the ELISA. Conclusions: The CLIA displayed satisfactory precision and agreement with ELISA for GADA, IA-2A, and ZnT8A detection. Our findings support the use of these automated immunoassays in large-scale population initiatives for diagnosing T1D, but we also highlight the need for further efforts to achieve better inter-assay harmonization. Full article
(This article belongs to the Section Clinical Laboratory Medicine)
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11 pages, 731 KB  
Article
Comparative Evaluation of Four Different Anti-CCP Assays for the Diagnosis of Rheumatoid Arthritis: A Diagnostic Performance Analysis
by Lydia Lamara Mahammed, Tamazouzt Hadjout, Asma Bensaci, Ryma Hamma, Ghalya Bousbia, Nawel Dahmani, Halima Ismail, Nadia Tamechmacht and Reda Djidjik
Diagnostics 2025, 15(10), 1293; https://doi.org/10.3390/diagnostics15101293 - 21 May 2025
Cited by 1 | Viewed by 9492
Abstract
Background/Objectives: Anti-cyclic citrullinated peptide (anti-CCP) antibodies are highly specific markers for rheumatoid arthritis (RA). Over the past decade, novel automating detection systems have been developed for anti-CCP detection. The present study aimed to evaluate the diagnostic performances of three fully automated anti-CCP [...] Read more.
Background/Objectives: Anti-cyclic citrullinated peptide (anti-CCP) antibodies are highly specific markers for rheumatoid arthritis (RA). Over the past decade, novel automating detection systems have been developed for anti-CCP detection. The present study aimed to evaluate the diagnostic performances of three fully automated anti-CCP assays in comparison to a conventional manual enzyme-linked immunosorbent assay (ELISA). Methods: One hundred ninety-nine patients with rheumatic symptoms (100 with RA and 99 without RA) were tested for anti-CCP autoantibodies using four assays: a manual-ELISA (EUROIMMUN®), two chemiluminescence immunoassays (CLIAs) performed on the MAGLUMI X3® and iFlash 1800® platforms, and an enzyme immunoassay (EIA) run on the UNI® analyzer. Results: The Kappa statistic indicated a moderate qualitative agreement among the EUROIMMUN, iFlash, and UNI assays (0.734 ≤ ĸ ≤ 0.778), while the MAGLUMI anti-CCP assay showed only weak-to-moderate agreement with the others (0.510 ≤ ĸ ≤ 0.628). A strong positive correlation was observed between anti-CCP levels measured by the four assays (0.747 ≤ rho ≤ 0.839). At the manufacturers’ cut-off values, sensitivities ranged from 76% to 99% and specificities from 69.7% to 99%, depending on the assay. However, at a fixed specificity of 95%, all the four assays showed good diagnostic performances for RA, with sensitivities ranging from 80% to 89% and positive likelihood ratios (LRs+) from 16 to 17.8. Conclusions: Our results revealed that at the manufacturers’ cut-offs, the UNI anti-CCP assay was the most valuable alternative to the conventional ELISA for diagnosing RA in our cohort. Nevertheless, after an appropriate adjustment of the thresholds, all the evaluated assays showed good diagnostic performances for RA. Full article
(This article belongs to the Section Clinical Laboratory Medicine)
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11 pages, 1028 KB  
Article
Potential for Misinterpretation in the Laboratory Diagnosis of Clostridioides difficile Infections
by Alexandra Kalacheva, Metodi Popov, Valeri Velev, Rositsa Stoyanova, Yordanka Mitova-Mineva, Tsvetelina Velikova and Maria Pavlova
Diagnostics 2025, 15(9), 1166; https://doi.org/10.3390/diagnostics15091166 - 3 May 2025
Cited by 1 | Viewed by 1561
Abstract
Background/Objective. Toxin-producing strains of Clostridioides difficile (C. diff) are the most commonly identified cause of healthcare-associated infection in the elderly. Risk factors include advanced age, hospitalization, prior or concomitant systemic antibacterial therapy, chemotherapy, and gastrointestinal surgery. Patients with unspecified and [...] Read more.
Background/Objective. Toxin-producing strains of Clostridioides difficile (C. diff) are the most commonly identified cause of healthcare-associated infection in the elderly. Risk factors include advanced age, hospitalization, prior or concomitant systemic antibacterial therapy, chemotherapy, and gastrointestinal surgery. Patients with unspecified and new-onset diarrhea with ≥3 unformed stools in 24 h are the target population for C. diff infection (CDI) testing. To present data on the risks of laboratory misdiagnosis in managing CDI. Materials. In two general hospitals, we examined 116 clinical stool specimens from hospitalized patients with acute diarrhea suspected of nosocomial or antibiotic-associated diarrhea (AAD) due to C. diff. Enzyme immunoassay (EIA) tests for the detection of C. diff toxins A (cdtA) and B (cdtB) in stool, automated CLIA assay for the detection of C. diff GDH antigen and qualitative determination of cdtA and B in human feces and anaerobic stool culture were applied for CDI laboratory diagnosis. MALDI-TOF (Bruker) was used to identify the presumptive anaerobic bacterial colonies. The following methods were used as confirmatory diagnostics: the LAMP method for the detection of Salmonella spp. and simultaneous detection of C. jejuni and C. coli, an E. coli Typing RT-PCR detection kit (ETEC, EHEC, STEC, EPEC, and EIEC), API 20E and aerobic stool culture methods. Results. A total of 40 toxigenic strains of C. diff were isolated from all 116 tested diarrheal stool samples, of which 38/40 produced toxin B and 2/40 strains were positive for both cdtA and cdtB. Of the stool samples positive for cdtA (6/50) and/or cdtB (44/50) by EIA, 33 were negative for C. diff culture but positive for the following diarrheal agents: Salmonella enterica subsp. arizonae (1/33, LAMP, culture, API 20E); C. jejuni (2/33, LAMP, culture, MALDI TOF); ETEC O142 (1/33), STEC O145 and O138 (2/33, E. coli RT-PCR detection kit, culture); C. perfringens (2/33, anaerobic culture, MALDI TOF); hypermycotic enterotoxigenic K. pneumonia (2/33) and enterotoxigenic P. mirabilis (2/33, culture; PCR encoding LT-toxin). Two of the sixty-six cdtB-positive samples (2/66) showed a similar misdiagnosis when analyzed using the CLIA method. However, the PCR analysis showed that they were cdtB-negative. In contrast, the LAMP method identified a positive result for C. jejuni in one sample, and another was STEC positive (stx1+/stx2+) by RT-PCR. We found an additional discrepancy in the CDI test results: EPEC O86 (RT-PCR eae+) was isolated from a fecal sample positive for GHA enzyme (CLIA) and negative for cdtA and cdtB (CLIA and PCR). However, the culture of C. diff was negative. These findings support the hypothesis that certain human bacterial pathogens that produce enterotoxins other than C. diff, as well as intestinal commensal microorganisms, including Klebsiella sp. and Proteus sp., contribute to false-positive EIA card tests for C. diff toxins A and B, which are the most widely used laboratory tests for CDI. Conclusions. CDI presents a significant challenge to clinical practice in terms of laboratory diagnostic management. It is recommended that toxin-only EIA tests should not be used as the sole diagnostic tool for CDI but should be limited to detecting toxins A and B. Accurate diagnosis of CDI requires a combination of laboratory diagnostic methods on which proper infection management depends. Full article
(This article belongs to the Section Diagnostic Microbiology and Infectious Disease)
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17 pages, 4883 KB  
Article
Prevalence of Blastocystis spp. and Other Gastrointestinal Pathogens Among Patients Admitted to Research Hospitals in Campania Region, Italy
by Marianna Ascierto, Annalisa Chianese, Francesco Foglia, Emiliana Finamore, Luciana Petrullo, Carla Zannella, Anna De Filippis, Maria Grazia Coppola and Massimiliano Galdiero
Pathogens 2025, 14(5), 425; https://doi.org/10.3390/pathogens14050425 - 27 Apr 2025
Cited by 2 | Viewed by 3295
Abstract
Background. Blastocystis spp. is a common protozoan found in the gastrointestinal tract, typically existing as a non-pathogenic organism in humans and other animals. However, it can become pathogenic when the immune system is compromised due to bacterial, viral, fungal, or other parasitic infections, [...] Read more.
Background. Blastocystis spp. is a common protozoan found in the gastrointestinal tract, typically existing as a non-pathogenic organism in humans and other animals. However, it can become pathogenic when the immune system is compromised due to bacterial, viral, fungal, or other parasitic infections, as well as systemic conditions, leading to symptomatic blastocystosis. Methods. Fecal samples were collected from patients at the University Hospital of Campania “Luigi Vanvitelli” and Cotugno Hospital in Naples. Among these samples, those that tested positive for Blastocystis spp. and were associated with other microbial infections were further analyzed. Bacterial co-infections were identified using immunochromatographic tests (ICTs) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Viral infections were detected using chemiluminescent immunoassay (CLIA), while fungal infections were diagnosed through microscopic examination and molecular biology techniques. Additionally, co-infections with other parasites were identified through microscopic analysis after Ridley’s concentration and Giemsa staining (O&P). Results. Out of the 2050 stool samples collected, 121 were positive for Blastocystis spp., of which 75 were associated with other infections. We identified the vacuolar form in patients co-infected with bacteria (n = 22), viruses (n = 30), fungi (n = 3), and other parasites (n = 20). Conclusions. Our findings indicated a higher incidence of the vacuolar form of Blastocystis spp. in symptomatic and immunocompromised patients, suggesting that a weakened immune system may increase the risk of contracting Blastocystis and other microbial infections. Full article
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11 pages, 2309 KB  
Article
Performance Evaluation of the New High-Sensitivity Cardiac Troponin I Immunoassay on CL-2600i Mindray Analyzer
by Flaminia Tomassetti, Denise Fiorelli, Edoardo Cappa, Alfredo Giovannelli, Martina Pelagalli, Silvia Velocci, Eleonora Nicolai, Marilena Minieri, Marco Alfonso Perrone, Sergio Bernardini and Massimo Pieri
Diagnostics 2025, 15(8), 1031; https://doi.org/10.3390/diagnostics15081031 - 18 Apr 2025
Viewed by 2725
Abstract
Background: International guidelines recommend the use of high-sensitivity cardiac troponin (hs-cTn) I and T methods for the detection of myocardial injury as a pre-requisite for the diagnosis of acute myocardial infarction (AMI) in patients admitted to the emergency department. Recently, Mindray (Mindray [...] Read more.
Background: International guidelines recommend the use of high-sensitivity cardiac troponin (hs-cTn) I and T methods for the detection of myocardial injury as a pre-requisite for the diagnosis of acute myocardial infarction (AMI) in patients admitted to the emergency department. Recently, Mindray (Mindray Bio-Medical Electronics Co., Ltd., Shenzhen, China) has introduced a new chemiluminescence immunoassay (CLIA) for the detection of the cTn complex. The present study aims to verify and validate the hs-cTnI Mindray assay on the new automated CL2600i analyzer compared to the routine Alinity-i series instrument by Abbott (Abbott, Chicago, IL, USA). Methods: This study evaluated linearity, precision through the 5 × 5 protocol, methodological comparison on plasma and serum matrices, hs-cTnI 99th percentile imprecision, and the hs-cTnI detection rate in a healthy population. Results: The results obtained proved that the performance of the Mindray hs-cTnI test on the CL2600i platform was closely comparable to the Abbott Alinity-i system (plasma R2: 0.974; serum R2: 0.995). The CVs were consistently low, and no significant differences were reported. Excellent analytical performance, with high sensitivity, was also observed in the healthy population (overall detection rate: 79%), as well as good linearity within the measuring range (R2: 0.994). Conclusions: The Mindray hs-cTnI test confirms its robustness and utility in routine practice as an advanced assay. The new technology, with more sensitive detection methods, may improve the accuracy and reliability of cardiac biomarker testing, ultimately leading to better outcomes in the management of patients with AMI and other cardiac conditions. Full article
(This article belongs to the Section Clinical Laboratory Medicine)
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