Clinical applications of volatilomic assays.

The study of metabolomics is revealing immense potential for diagnosis, therapy monitoring, and understanding of pathogenesis processes. Volatilomics is a subcategory of metabolomics interested in the detection of molecules that are small enough to be released in the gas phase. Volatile compounds produced by cellular processes are released into the blood and lymph, and can reach the external environment through different pathways, such as the blood-air interface in the lung that are detected in breath, or the blood-water interface in the kidney that leads to volatile compounds detected in urine. Besides breath and urine, additional sources of volatile compounds such as saliva, blood, feces, and skin are available. Volatilomics traces its roots back over fifty years to the pioneering investigations in the 1970s. Despite extensive research, the field remains in its infancy, hindered by a lack of standardization despite ample experimental evidence. The proliferation of analytical instrumentations, sample preparations and methods of volatilome sampling still make it difficult to compare results from different studies and to establish a common standard approach to volatilomics. This review aims to provide an overview of volatilomics' diagnostic potential, focusing on two key technical aspects: sampling and analysis. Sampling poses a challenge due to the susceptibility of human samples to contamination and confounding factors from various sources like the environment and lifestyle. The discussion then delves into targeted and untargeted approaches in volatilomics. Some case studies are presented to exemplify the results obtained so far. Finally, the review concludes with a discussion on the necessary steps to fully integrate volatilomics into clinical practice.

SARS-CoV-2 infection triggers more potent antibody-dependent cellular cytotoxicity (ADCC) responses than mRNA-, vector-, and inactivated virus-based COVID-19 vaccines.

Neutralizing antibodies (NAbs) are elicited after infection and vaccination and have been well studied. However, their antibody-dependent cellular cytotoxicity (ADCC) functionality is still poorly characterized. Here, we investigated ADCC activity in convalescent sera from infected patients with wild-type (WT) severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) or omicron variant compared with three coronavirus disease 2019 (COVID-19) vaccine platforms and postvaccination breakthrough infection (BTI). We analyzed ADCC activity targeting SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in convalescent sera following WT SARS-CoV-2-infection (n = 91), including symptomatic and asymptomatic infections, omicron-infection (n = 8), COVID-19 vaccination with messenger RNA- (mRNA)- (BNT162b2 or mRNA-1273, n = 77), adenovirus vector- (n = 41), and inactivated virus- (n = 46) based vaccines, as well as post-mRNA vaccination BTI caused by omicron (n = 28). Correlations between ADCC, binding, and NAb titers were reported. ADCC was elicited within the first month postinfection and -vaccination and remained detectable for ≥3 months. WT-infected symptomatic patients had higher S-specific ADCC levels than asymptomatic and vaccinated individuals. Also, no difference in N-specific ADCC activity was seen between symptomatic and asymptomatic patients, but the levels were higher than the inactivated vaccine. Notably, omicron infection showed reduced overall ADCC activity compared to WT SARS-CoV-2 infection. Although post-mRNA vaccination BTI elicited high levels of binding and NAbs, ADCC activity was significantly reduced. Also, there was no difference in ADCC levels across the four vaccines, although NAbs and binding antibody titers were significantly higher in mRNA-vaccinated individuals. All evaluated vaccine platforms are inferior in inducing ADCC compared to natural infection with WT SARS-CoV-2. The inactivated virus-based vaccine can induce N-specific ADCC activity, but its relevance to clinical outcomes requires further investigation. Our data suggest that ADCC could be used to estimate the extra-neutralization level against COVID-19 and provides evidence that vaccination should focus on other Fc-effector functions besides NAbs. Also, the decreased susceptibility of the omicron variant to ADCC offers valuable guidance for forthcoming efforts to identify the specific targets of antibodies facilitating ADCC.

Circulating calprotectin as a potential biomarker of persistent olfactory dysfunctions in Post-COVID-19 patients.

BACKGROUND: This longitudinal prospective study aims to investigate the potential of circulating calprotectin (cCLP) as a biomarker in persistent olfactory dysfunctions following COVID-19 infection. METHODS: Thirty-six patients with persistent hyposmia or anosmia post COVID-19 were enrolled (HT0) and re-evaluated after three months of olfactory training (HT1). Two control groups included 18 subjects without olfactory defects post COVID-19 (CG1) and 18 healthy individuals (CG2). Nasal brushing of the olfactory cleft and blood collection were performed to assess circulating calprotectin levels. RESULTS: Higher calprotectin levels were observed in serum and nasal supernatant of hyposmic patients (HT0) compared to control groups (CG1 and CG2). Post-olfactory training (HT1), olfactory function improved significantly, paralleled by decreased calprotectin levels in serum and nasal samples. Circulating calprotectin holds potential as a biomarker in persistent olfactory dysfunctions after COVID-19. The decrease in calprotectin levels post-olfactory training implies a role in monitoring and evaluating treatment responses. DISCUSSION AND CONCLUSIONS: These findings contribute to the growing literature on potential biomarkers in post-COVID-19 olfactory dysfunctions and underscore the importance of investigating novel biomarkers for personalized patient management. Nevertheless, further studies are needed to validate the application of calprotectin assay in nasal diseases and its correlation with nasal cytology.

HTA model for laboratory medicine technologies: overview of approaches adopted in some international agencies.

The Health Technology Assessment (HTA) Working Group of the Emerging Technology Division of International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) aims to develop a methodological approach for producing structured HTA information for laboratory medicine technologies. This approach seeks to support decision-making processes at the country, regional, and/or hospital levels regarding the introduction of specific technologies. The focus of this model will primarily be on defining assessment elements within the domains of 'organizational aspects' and 'costs and economic evaluations', potentially differentiated by the type of diagnostic technology (e.g., genetic tests, molecular tests). To achieve this project's goal, a literature review and examination of websites of international HTA agencies have been conducted. The research aims to identify multidisciplinary methodological approaches used to assess laboratory diagnostic technologies and to pinpoint the domains and assessment elements utilized. We found 7 methodological articles describing methodological approaches adopted to assess laboratory diagnostic technologies. Among the HTA organizations considered, 23 reports were found, of which 7 were produced by the European Network of HTA (EUnetHTA), 4 by the National Institute for Health and Care Excellence Diagnostic Assessment Program (NICE DAP), and 12 by other HTA agencies. The EUnetHTA reports were rapid collaborative assessments covering various domains, while the NICE DAP reports focused on diagnostic guidances, including descriptions of technologies, clinical need and practice, diagnostic tests, accuracy, effectiveness, and cost-effectiveness. Finally, a survey targeting laboratory professionals will be conducted to introduce assessment elements, differentiated by the type of diagnostic technology, primarily for organizational and economic domains.

Contribution of laboratory medicine and emerging technologies to cardiovascular risk reduction via exposome analysis: an opinion of the IFCC Division on Emerging Technologies.

This opinion article highlights the critical role of laboratory medicine and emerging technologies in cardiovascular risk reduction through exposome analysis. The exposome encompasses all external and internal exposures an individual faces throughout their life, influencing the onset and progression of cardiovascular diseases (CVD). Integrating exposome data with genetic information allows for a comprehensive understanding of the multifactorial causes of CVD, facilitating targeted preventive interventions. Laboratory medicine, enhanced by advanced technologies such as metabolomics and artificial intelligence (AI), plays a pivotal role in identifying and mitigating these exposures. Metabolomics provides detailed insights into metabolic changes triggered by environmental factors, while AI efficiently processes complex datasets to uncover patterns and associations. This integration fosters a proactive approach in public health and personalized medicine, enabling earlier detection and intervention. The article calls for global implementation of exposome technologies to improve population health, emphasizing the need for robust technological platforms and policy-driven initiatives to seamlessly integrate environmental data with clinical diagnostics. By harnessing these innovative technologies, laboratory medicine can significantly contribute to reducing the global burden of cardiovascular diseases through precise and personalized risk mitigation strategies.

Laboratory Diagnosis of Intrathecal Synthesis of Immunoglobulins: A Review about the Contribution of OCBs and K-index.

The diagnosis of MS relies on a combination of imaging, clinical examinations, and biological analyses, including blood and cerebrospinal fluid (CSF) assessments. G-Oligoclonal bands (OCBs) are considered a "gold standard" for MS diagnosis due to their high sensitivity and specificity. Recent advancements have involved the introduced of kappa free light chain (k-FLC) assay into cerebrospinal fluid (CSF) and serum (S), along with the albumin quotient, leading to the development of a novel biomarker known as the "K-index" or "k-FLC index". The use of the K-index has been recommended to decrease costs, increase laboratory efficiency, and to skip potential subjective operator-dependent risk that could happen during the identification of OCBs profiles. This review aims to provide a comprehensive overview and analysis of recent scientific articles, focusing on updated methods for MS diagnosis with an emphasis on the utility of the K-index. Numerous studies indicate that the K-index demonstrates high sensitivity and specificity, often comparable to or surpassing the diagnostic accuracy of OCBs evaluation. The integration of the measure of the K-index with OCBs assessment emerges as a more precise method for MS diagnosis. This combined approach not only enhances diagnostic accuracy, but also offers a more efficient and cost-effective alternative.

Role of miR-9 in Modulating NF-κB Signaling and Cytokine Expression in COVID-19 Patients.

Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus, has had a significant impact on global health, with severe cases often characterized by a worsening cytokine storm. Since it has been described that the NF-κB signaling pathway, regulated by microRNAs, could play a pivotal role in the inflammatory response, in this study, the role of miR-9 in modulating NF-κB signaling and inflammatory cytokine expression in COVID-19 patients was investigated. This observational retrospective single-center study included 41 COVID-19 patients and 20 healthy controls. Serum samples were analyzed for miR-9, NF-κB, and IκBα expression levels using RT-PCR. The expression levels and production of pro-inflammatory cytokines IL-6, IL-1ß, and TNF-α were measured using RT-PCR and ELISA. Statistical analyses, including correlation and regression, were conducted to explore relationships between these variables. COVID-19 patients, particularly non-survivors, exhibited significantly higher miR-9 and NF-κB levels compared to controls. A strong positive correlation was found between miR-9 and NF-κB expression (r = 0.813, p < 0.001). NF-κB levels were significantly correlated with IL-6 (r = 0.971, p < 0.001), IL-1ß (r = 0.968, p < 0.001), and TNF-α (r = 0.968, p < 0.001). Our findings indicate that miR-9 regulates NF-κB signaling and inflammation in COVID-19. Elevated miR-9 levels in non-survivors suggest its potential as a severity biomarker. While COVID-19 cases have decreased, targeting miR-9 and NF-κB could improve outcomes for other inflammatory conditions, including autoimmune diseases, highlighting the need for continued research in this area.

Correlation analysis between auto-immunological and mutational profiles in myelodysplastic syndromes.

OBJECTIVE AND DESIGN: Systemic-Inflammatory-Autoimmune-Diseases (SIAD) is increasingly considered in Myelodysplastic-Syndromes (MDS). In this line, we evaluated the MDS auto-immunological profile, correlating it to the mutational landscape, trying to identify a molecular-genetic trigger agent related to SIAD. METHODS AND MATERIALS: Eighty-one MDS were enrolled and t-NGS was performed. Anti-Nuclear-Antibodies (ANA) were tested, and ANA-antigenic-specificity was characterized by ANA-profile, ENA-screen, anti-dsDNA. Non-Hematological-Patients (NHP) and Healthy-Donors (HD) were used as controls. RESULTS: At clinically relevant cut-off (≥ 1:160), ANA was significantly more frequent in MDS, while ANA-antigenic-specificity showed a low association rate. ANA ≥ 1:160-positive MDS showed a mutational landscape similar to ANA-negative/ANA < 1:160 MDS. No significant correlations between mutational and immunological profiles were found and UBA1 mutations, related to VEXAS, were absent. CONCLUSIONS: Although ANA-positivity was found to be increased in MDS, the low ANA-antigenic-specificity suggests that autoantibodies didn't recognize autoimmune-pathognomonic antigens. The lack of relationship between genetic profile and ANA-positivity, suggests that MDS genetic variants may not be the direct cause of SIAD.

A new door to a different world: opportunities from the metaverse and the raise of meta-medical laboratories.

OBJECTIVES: In the digital age, the metaverse has emerged with impressive potential for many segments of society. The metaverse could be presented as a parallel dimension able to enhance the physical world as well as our actions and decisions in it with the objective to use a coalition between the natural and virtual worlds for value creation. Our aim was to elaborate on the impact of the metaverse on laboratory medicine. METHODS: Based on the available evidence, literature and reports, we analyzed the different perspectives of the metaverse on laboratory medicine and the needs for an efficient transition. RESULTS: The convergence and integration of technologies in the metaverse will participate to the reimagination of laboratory medicine services with augmented services, users' experiences, efficiency, and personalized care. The revolution around the metaverse offers different opportunities for laboratory medicine but also open multiple related challenges that are presented in this article. CONCLUSIONS: Scientific societies, multidisciplinary teams and specialists in laboratory medicine must prepare the integration metaverse and meta-medical laboratories, raise the awareness, educate, set guidance to obtain a maximum of value and mitigate potential adverse consequences.

Emerging technology: a definition for laboratory medicine.

The term "emerging technology" (ET) is used extensively, and there are numerous definitions offered, but to our knowledge, none specifically encompass the field of laboratory medicine. An ET definition that incorporates the overarching IFCC aim of "Advancing excellence in laboratory medicine to support healthcare worldwide" would clarify discussions. We discuss key aspects of the term "emerging technology(ies)" as it applies to laboratory medicine with a view to laying the foundations for a practical definition for the profession and propose the definition of an ET as "An analytical method or device that by virtue of its stage of development, translation into broad routine clinical practice, or geographical adoption and implementation has the potential to add value to clinical diagnostics".

Toolkit for emerging technologies in laboratory medicine.

An emerging technology (ET) for laboratory medicine can be defined as an analytical method (including biomarkers) or device (software, applications, and algorithms) that by its stage of development, translation into broad routine clinical practice, or geographical adoption and implementation has the potential to add value to clinical diagnostics. Considering the laboratory medicine-specific definition, this document examines eight key tools, encompassing clinical, analytical, operational, and financial aspects, used throughout the life cycle of ET implementation. The tools provide a systematic approach starting with identifying the unmet need or identifying opportunities for improvement (Tool 1), forecasting (Tool 2), technology readiness assessment (Tool 3), health technology assessment (Tool 4), organizational impact map (Tool 5), change management (Tool 6), total pathway to method evaluation checklist (Tool 7), and green procurement (Tool 8). Whilst there are differences in clinical priorities between different settings, the use of this set of tools will help support the overall quality and sustainability of the emerging technology implementation.

Where is laboratory medicine headed in the next decade? Partnership model for efficient integration and adoption of artificial intelligence into medical laboratories.

OBJECTIVES: The field of artificial intelligence (AI) has grown in the past 10 years. Despite the crucial role of laboratory diagnostics in clinical decision-making, we found that the majority of AI studies focus on surgery, radiology, and oncology, and there is little attention given to AI integration into laboratory medicine. METHODS: We dedicated a session at the 3rd annual European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) strategic conference in 2022 to the topic of AI in the laboratory of the future. The speakers collaborated on generating a concise summary of the content that is presented in this paper. RESULTS: The five key messages are (1) Laboratory specialists and technicians will continue to improve the analytical portfolio, diagnostic quality and laboratory turnaround times; (2) The modularized nature of laboratory processes is amenable to AI solutions; (3) Laboratory sub-specialization continues and from test selection to interpretation, tasks increase in complexity; (4) Expertise in AI implementation and partnerships with industry will emerge as a professional competency and require novel educational strategies for broad implementation; and (5) regulatory frameworks and guidances have to be adopted to new computational paradigms. CONCLUSIONS: In summary, the speakers opine that the ability to convert the value-proposition of AI in the laboratory will rely heavily on hands-on expertise and well designed quality improvement initiative from within laboratory for improved patient care.

Blood-Brain Barrier Dysfunction and Aß42/40 Ratio Dose-Dependent Modulation with the ApoE Genotype within the ATN Framework.

The definition of Alzheimer's disease (AD) now considers the presence of the markers of amyloid (A), tau deposition (T), and neurodegeneration (N) essential for diagnosis. AD patients have been reported to have increased blood-brain barrier (BBB) dysfunction, but that has not been tested within the ATN framework so far. As the field is moving towards the use of blood-based biomarkers, the relationship between BBB disruption and AD-specific biomarkers requires considerable attention. Moreover, other factors have been previously implicated in modulating BBB permeability, including age, gender, and ApoE status. A total of 172 cognitively impaired individuals underwent cerebrospinal fluid (CSF) analysis for AD biomarkers, and data on BBB dysfunction, demographics, and ApoE status were collected. Our data showed that there was no difference in BBB dysfunction across different ATN subtypes, and that BBB damage was not correlated with cognitive impairment. However, patients with BBB disruption, if measured with a high Qalb, had low Aß40 levels. ApoE status did not affect BBB function but had a dose-dependent effect on the Aß42/40 ratio. These results might highlight the importance of understanding dynamic changes across the BBB in future studies in patients with AD.

Inflammageing and Cardiovascular System: Focus on Cardiokines and Cardiac-Specific Biomarkers.

The term "inflammageing" was introduced in 2000, with the aim of describing the chronic inflammatory state typical of elderly individuals, which is characterized by a combination of elevated levels of inflammatory biomarkers, a high burden of comorbidities, an elevated risk of disability, frailty, and premature death. Inflammageing is a hallmark of various cardiovascular diseases, including atherosclerosis, hypertension, and rapid progression to heart failure. The great experimental and clinical evidence accumulated in recent years has clearly demonstrated that early detection and counteraction of inflammageing is a promising strategy not only to prevent cardiovascular disease, but also to slow down the progressive decline of health that occurs with ageing. It is conceivable that beneficial effects of counteracting inflammageing should be most effective if implemented in the early stages, when the compensatory capacity of the organism is not completely exhausted. Early interventions and treatments require early diagnosis using reliable and cost-effective biomarkers. Indeed, recent clinical studies have demonstrated that cardiac-specific biomarkers (i.e., cardiac natriuretic peptides and cardiac troponins) are able to identify, even in the general population, the individuals at highest risk of progression to heart failure. However, further clinical studies are needed to better understand the usefulness and cost/benefit ratio of cardiac-specific biomarkers as potential targets in preventive and therapeutic strategies for early detection and counteraction of inflammageing mechanisms and in this way slowing the progressive decline of health that occurs with ageing.

Partial Loss of Function ABCA12 Mutations Generate Reduced Deposition of Glucosyl-Ceramide, Leading to Patchy Ichthyosis and Erythrodermia Resembling Erythrokeratodermia Variabilis et Progressiva (EKVP).

Ichthyoses are genetically determined cornification disorders of the epidermis characterized by the presence of different degrees of scaling, hyperkeratosis, and erythroderma often associated with palmoplantar keratoderma. Different classifications of these diseases have been proposed, often based upon the involved genes and/or the clinical presentation. The clinical features of these diseases present some overlap of phenotypes among distinct genetic entities, depending mainly on the penetrance of mutations. In this study, using a clinical, genetic, and molecular approach, we analyzed a family with two affected members who had clinical and histological features resembling erythrokeratodermia variabilis (EKV) or a type of erythrodermic hyperkeratosis with palmoplantar keratoderma. Despite of the clinical presentation, we demonstrated that the affected patients were genetically double heterozygous for two different mutations in the ABCA12 gene, known to be responsible for harlequin ichthyosis. To explain the mild phenotype of our patients, we performed a molecular characterization of the skin. In the upper layers of the epidermis, the results showed a patchy presence of the glucosyl-ceramides (GlcCer), which is the lipid transported by ABCA12, fundamental in contributing to skin impermeability. Indeed, the two mutations detected do not completely abolish ABCA12 activity, indicating that the mild phenotype is due to a partial loss of function of the enzyme, thus giving rise to an intermediate phenotype resembling EKVP, due to a partial depletion of GlcCer deposition.

Epithelial-to-Mesenchymal Transition Gene Signature in Circulating Melanoma Cells: Biological and Clinical Relevance.

The most promising method for monitoring patients with minimal morbidity is the detection of circulating melanoma cells (CMCs). We have shown that CD45-CD146+ABCB5+ CMCs identify a rare primitive stem/mesenchymal CMCs population associated with disease progression. The epithelial-to-mesenchymal transition (EMT) confers cancer cells a hybrid epithelial/mesenchymal phenotype promoting metastatization. Thus, we investigated the potential clinical value of the EMT gene signature of these primitive CMCs. A reliable quantitative real-time polymerase chain reaction (qRT-PCR) protocol was settled up using tumor cell lines RNA dilutions. Afterwards, immune-magnetically isolated CMCs from advanced melanoma patients, at onset and at the first checkpoint (following immune or targeted therapy), were tested for the level of EMT hallmarks and EMT transcription factor genes. Despite the small cohort of patients, we obtained promising results. Indeed, we observed a deep gene rewiring of the EMT investigated genes: in particular we found that the EMT gene signature of isolated CMCs correlated with patients' clinical outcomes. In conclusion, We established a reliable qRT-PCR protocol with high sensitivity and specificity to characterize the gene expression of isolated CMCs. To our knowledge, this is the first evidence demonstrating the impact of immune or targeted therapies on EMT hallmark gene expressions in CMCs from advanced melanoma patients.

OTX Genes in Adult Tissues.

OTX homeobox genes have been extensively studied for their role in development, especially in neuroectoderm formation. Recently, their expression has also been reported in adult physiological and pathological tissues, including retina, mammary and pituitary glands, sinonasal mucosa, in several types of cancer, and in response to inflammatory, ischemic, and hypoxic stimuli. Reactivation of OTX genes in adult tissues supports the notion of the evolutionary amplification of functions of genes by varying their temporal expression, with the selection of homeobox genes from the "toolbox" to drive or contribute to different processes at different stages of life. OTX involvement in pathologies points toward these genes as potential diagnostic and/or prognostic markers as well as possible therapeutic targets.

The COVID-19 pandemic: viral variants and vaccine efficacy.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has prompted the scientific community and the pharmaceutical companies to put maximum efforts into developing vaccines to contain the spread of this disease. Presently, many vaccines have been developed and authorized for use in human beings in different countries. In particular, in Europe to date, the Pfizer-BioNTech, Moderna, AstraZeneca and Janssen COVID-19 vaccines have been authorized. All of them are based on a version of the spike (S) glycoprotein characterized at the beginning of the pandemic. However, they differ by their level of efficacy against COVID-19. SARS-COV-2, like other RNA viruses, mutates continually. Genome sequencing analysis shows a nucleotide substitution rate of about 1 × 10-3 substitutions per year that leads to the emergence of variants through point mutations, insertions, deletions and recombination. There is concern about the ability of the current vaccines to protect against emerging viral variants. Mutations in the S-glycoprotein may affect transmission dynamics and the risk of immune escape. In this review, we address the different technological platforms in use for developing COVID-19 vaccines, the impact of emerging viral variants on virus transmission, hospitalization, and response to current vaccines, as well as rare but important adverse reactions to them. Finally, different methods for measuring antibody response to the vaccines, including the importance of using the WHO International Standard to calibrate immunoassays accurately to an arbitrary unit, to reduce interlaboratory variation and to create a common language for reporting results, are reported.

Evaluation of serological anti-SARS-CoV-2 chemiluminescent immunoassays correlated to live virus neutralization test, for the detection of anti-RBD antibodies as a relevant alternative in COVID-19 large-scale neutralizing activity monitoring.

The Spike-Receptor Binding Domain (S-RBD) is considered the most antigenic protein in SARS-CoV-2 and probably the key player in SARS-CoV-2 immune response. Quantitative immunoassays may help establish an anti-RBD Abs threshold as an indication of protective immunity. Since different immunoassays are commercial, the standard reference method for the neutralizing activity is the live Virus Neutralization Test (VNT). In this study, anti-RBD IgG levels were detected with two chemiluminescent immunoassays in paucisymptomatic, symptomatic and vaccinated subjects, and their neutralizing activity was correlated to VNT titer, using SARS-CoV-2 original and British variant strains. Both immunoassays confirmed higher anti-RBD Abs levels in vaccinated subjects. Furthermore, despite different anti-RBD Abs median concentrations between the immunoassays, a strong positive correlation with VNT was observed. In conclusion, although the SARS-CoV-2 immune response heterogeneity, the use of immunoassays can help in large-scale monitoring of COVID-19 samples, becoming a valid alternative to VNT test for diagnostic routine laboratories.

Validation of a quantitative lateral flow immunoassay (LFIA)-based point-of-care (POC) rapid test for SARS-CoV-2 neutralizing antibodies.

With the widespread use of coronavirus disease 2019 (COVID-19) vaccines, a rapid and reliable method to detect SARS-CoV-2 neutralizing antibodies (NAbs) is extremely important for monitoring vaccine effectiveness and immunity in the population. The purpose of this study was to evaluate the performance of the RapiRead™ reader and the TestNOW™ COVID-19 NAb rapid point-of-care (POC) test for quantitative measurement of antibodies against the spike protein receptor-binding domain of severe respiratory syndrome coronavirus 2 (SARS-CoV-2) in different biological matrices compared to chemiluminescence immunoassay (CLIA) methods. Ninety-four samples were collected and analyzed using a RapiRead™ reader and TestNOW™ COVID-19 NAb kits for detecting neutralizing antibodies, and then using two CLIAs. The data were compared statistically using the Kruskal-Wallis test for more than two groups or the Mann-Whitney test for two groups. Specificity and sensitivity were evaluated using a receiver operating characteristic (ROC) curve. Good correlation was observed between the rapid lateral flow immunoassay (LFIA) test system and both CLIA methods. RapiRead™ reader/TestNOW™ COVID-19 NAb vs. Maglumi: correlation coefficient (r) = 0.728 for all patients; r = 0.841 for vaccinated patients. RapiRead™ reader/TestNOW™ COVID-19 NAb vs. Mindray: r = 0.6394 in all patients; r = 0.8724 in vaccinated patients. The time stability of the POC serological test was also assessed considering two times of reading, 12 and 14 minutes. The data revealed no significant differences. The use of a RapiRead™ reader and TestNOW™ COVID-19 NAb assay is a quantitative, rapid, and valid method for detecting SARS-CoV-2 neutralizing antibodies and could be a useful tool for screening studies of SARS-CoV-2 infection and assessing the efficacy of vaccines in a non-laboratory context.