Comparison of Different Test Systems for the Detection of Antiphospholipid Antibodies in a Chinese Cohort.

Background: Diagnosis of antiphospholipid syndrome (APS) is based on the positivity of laboratory criteria antiphospholipid antibodies (aPLs). Test results for aPLs could be contradictory among different detection methods as well as commercial manufacturers. This study aimed to assess and compare the diagnostic and analytic performances of four commercial assays prevalently used in China. Methods: A total of 313 patients including 100 patients diagnosed with primary APS, 52 with APS secondary to SLE, 71 with SLE, and 90 health controls were recruited. Serum IgG, IgM, and IgA for aCL, and aß2GPI antibodies were detected with two ELISA and two CLIA systems, and test system with the best diagnostic value was explored of its correlation with key clinical features. Results: CLIA by YHLO Biotech Co. was considered as the system with the best predictive power, where 58.55 and 57.89% of APS patients were positive for aCL or aß2GPI for at least one antibody (IgG or IgM or IgA). Overall, CLIA showed better performance characteristics than traditional ELISA test systems. Conclusion: CLIA was considered as a better platform for aPL detection in APS diagnosis. A combination of other detection platforms could assist in differential diagnosis as well as in identifying high-risk patients.

An evaluation of the Unyvero pneumonia system for rapid detection of microorganisms and resistance markers of lower respiratory infections-a multicenter prospective study on ICU patients.

Rapid diagnosis of microorganisms and antibiotic resistance is vital for the appropriate treatment of patients with lower respiratory infections, especially for patients in Intensive Care Unit. We conducted a multicenter prospective study to evaluate the ability of the Unyvero pneumonia system for rapid detection from bronchoalveolar lavage fluid (BALF) in China. Eighty-four patients with lower respiratory infections were enrolled, and their BALF samples were collected, and Unyvero, a rapid molecular diagnostic sample-to-answer solution based on multiple PCRs, was applied to detect 21 types of pathogens and 19 types of resistance markers, compared to a routine bacterial culture method. The overall concordance of Unyvero and routine culture was 69/84 (82.1%). Unyvero detected more microorganisms than routine culture (38.1% vs 27.4%, P<0.05) and reported multi-pathogens in more patients than routine culture (10.7% vs 2.4%, P=0.01). The overall sensitivity and specificity of Unyvero for bacteria detection were 84.0% and 98.0%. Besides, Unyvero showed a good performance for antibiotic-resistant bacteria, except Pseudomonas aeruginosa. The concordance was 87.5-100% for methicillin-resistant Staphylococcus aureus and carbapenem-resistant isolates but was only 20-33.3% for Pseudomonas aeruginosa. The high-level semi-quantitative signal intensity of microorganisms detected positive by Unyvero correlates well with positive bacterial cultures. For specimens that were exposed to antibiotic treatment, the Unyvero pneumonia system showed a high concordance with routine bacterial culture and performs well for the detection of antibiotic-resistant bacteria, especially, carbapenem-resistant Klebsiella pneumoniae. It shows promise in guiding the clinical use of antibiotics, such as ceftazidime/avibactam. However, the system needs improvement in detecting resistance markers of Pseudomonas aeruginosa.

A Highly Automated Mobile Laboratory for On-site Molecular Diagnostics in the COVID-19 Pandemic.

BACKGROUND: Infectious disease outbreaks such as the COVID-19 (coronavirus disease 2019) pandemic call for rapid response and complete screening of the suspected community population to identify potential carriers of pathogens. Central laboratories rely on time-consuming sample collection methods that are rarely available in resource-limited settings. METHODS: We present a highly automated and fully integrated mobile laboratory for fast deployment in response to infectious disease outbreaks. The mobile laboratory was equipped with a 6-axis robot arm for automated oropharyngeal swab specimen collection; virus in the collected specimen was inactivated rapidly using an infrared heating module. Nucleic acid extraction and nested isothermal amplification were performed by a "sample in, answer out" laboratory-on-a-chip system, and the result was automatically reported by the onboard information platform. Each module was evaluated using pseudovirus or clinical samples. RESULTS: The mobile laboratory was stand-alone and self-sustaining and capable of on-site specimen collection, inactivation, analysis, and reporting. The automated sampling robot arm achieved sampling efficiency comparable to manual collection. The collected samples were inactivated in as short as 12 min with efficiency comparable to a water bath without damage to nucleic acid integrity. The limit of detection of the integrated microfluidic nucleic acid analyzer reached 150 copies/mL within 45 min. Clinical evaluation of the onboard microfluidic nucleic acid analyzer demonstrated good consistency with reverse transcription quantitative PCR with a κ coefficient of 0.979. CONCLUSIONS: The mobile laboratory provides a promising solution for fast deployment of medical diagnostic resources at critical junctions of infectious disease outbreaks and facilitates local containment of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) transmission.

Pulse-Controlled Amplification-A new powerful tool for on-site diagnostics under resource limited conditions.

BACKGROUND: Molecular diagnostics has become essential in the identification of many infectious and neglected diseases, and the detection of nucleic acids often serves as the gold standard technique for most infectious agents. However, established techniques like polymerase chain reaction (PCR) are time-consuming laboratory-bound techniques while rapid tests such as Lateral Flow Immunochromatographic tests often lack the required sensitivity and/or specificity. METHODS/PRINCIPLE FINDINGS: Here we present an affordable, highly mobile alternative method for the rapid identification of infectious agents using pulse-controlled amplification (PCA). PCA is a next generation nucleic acid amplification technology that uses rapid energy pulses to heat microcyclers (micro-scale metal heating elements embedded directly in the amplification reaction) for a few microseconds, thus only heating a small fraction of the reaction volume. The heated microcyclers cool off nearly instantaneously, resulting in ultra-fast heating and cooling cycles during which classic amplification of a target sequence takes place. This reduces the overall amplification time by a factor of up to 10, enabling a sample-to-result workflow in just 15 minutes, while running on a small and portable prototype device. In this proof of principle study, we designed a PCA-assay for the detection of Yersinia pestis to demonstrate the efficacy of this technology. The observed detection limits were 434 copies per reaction (purified DNA) and 35 cells per reaction (crude sample) respectively of Yersinia pestis. CONCLUSIONS/SIGNIFICANCE: PCA offers fast and decentralized molecular diagnostics and is applicable whenever rapid, on-site detection of infectious agents is needed, even under resource limited conditions. It combines the sensitivity and specificity of PCR with the rapidness and simplicity of hitherto existing rapid tests.

Performance evaluation of the highly sensitive histidine-rich protein 2 rapid test for plasmodium falciparum malaria in North-West Tanzania.

BACKGROUND: Precise detection of Plasmodium infections in community surveys is essential for effective malaria control. Microscopy and rapid diagnostic tests (RDTs) are the major techniques used to identify malaria infections in the field-based surveys. Although microscopy is still considered as the gold standard, RDTs are increasingly becoming versatile due to their rapid and adequate performance characteristics. METHODS: A malaria prevalence cross-sectional survey was carried out in north-western Tanzania in 2016, aimed at appraising the performance of high sensitivity Plasmodium falciparum (HSPf) tests compared to SD Bioline Pf and microscopy in detecting P. falciparum infections. A total of 397 individuals aged five years and above were tested for P. falciparum infections. The sensitivity, specificity, positive, and negative predictive values (PPV and NPV) of microscopy, Pf RDT and HSPf RDT was determined using PCR as the gold standard method. RESULTS: The prevalence of P. falciparum infections determined by microscopy, SD Bioline Pf, HSPf and PCR was 21.9, 27.7, 33.3 and 43.2%, respectively. The new HSPf RDT had significantly higher sensitivity (98.2%) and specificity (91.6%) compared to the routinely used SD Bioline Pf RDT(P < 0.001). The positive predictive value (PPV) was 81.8% and the negative predictive value (NPV) was 99.2% for the routinely used SD Bioline Pf RDT. Moreover, HSPf RDT had sensitivity of 69% and specificity of 76.8% compared to microscopy. The PPV was 45.5% and the NPV was 89.8% for microscopy. Furthermore, the analytical sensitivity test indicated that the newly developed HSPf RDT had lower detection limits compared to routinely used SD Bioline RDT. CONCLUSIONS: HSPf RDT had better performance when compared to both microscopy and the currently used malaria RDTs. The false negativity could be associated with the low parasite density of the samples. False positivity may be related to the limitations of the expertise of microscopists or persistent antigenicity from previous infections in the case of RDTs. Nevertheless, HS PfRDT performed better compared to routinely used Pf RDT, and microscopy in detecting malaria infections. Therefore, HS Pf RDT presents the best alternative to the existing commercial/regularly available RDTs due to its sensitivity and specificity, and reliability in diagnosing malaria infections.

[Application of Microfluidics in Molecular Diagnostics].

In recent years, molecular diagnostics has been the most promising branch of in vitro diagnosis(IVD) due to its high sensitivity and specificity. However, it's not suitable for the research of molecule with macroscopic tools. Microfluidics can achieve precise control of micro-fluid and has been widely applied in molecular diagnostics because of its advantages such as lower sample consumption, shorter reaction time, and easier to integrate. Molecular diagnostics has made great development in methodology and automatic integration based on microfluidics. In this paper, we introduce the applications of microfluidics in molecular diagnostics and analysis the challenges of it.

Comparison of DNA extraction methods and real-time PCR assays for the molecular diagnostics of chronic Chagas disease.

Aim: This work aimed to compare the sensitivity of four protocols for the detection of Trypanosoma cruzi DNA in 98 blood samples from chronic Chagas disease patients. Materials & methods: Two DNA extraction (automated and manual) methods and two T. cruzi satellite DNA qPCRs (with a recent design and the usually used set of primers) were analyzed. Results: Both DNA extraction methods and qPCR assays tested in this work gave comparable qualitative results, although the lowest Ct values were obtained when samples were analyzed using the new set of primers for T. cruzi satellite DNA. Conclusion: Our results encourage the implementation of automated DNA extraction systems and the new T. cruzi qPCR for the molecular diagnostics and treatment response monitoring of chronic Chagas disease patients.

Testagem universal para hepatite viral C em gestantes no pré-natal / Universal testing for viral hepatitis C in prenatal pregnant women

INTRODUÇÃO: Estima-se que a prevalencia de hepatite C entre gestantes no Brasil varie entre 0,2 e 1,4%, entretanto, a partir de 2014 a taxa de deteccao da doenca entre mulheres em idade fertil dobrou no pais, apos a incorporacao pelo Sistema Unico de Saude de antivirais de acao direta com alta efetividade e seguranca. O risco de transmissao vertical e variavel e depende de fatores como o correto planejamento de procedimentos obstetricos, da viremia materna, de coinfeccao por HIV, entre outros. A hepatite C na gravidez esta relacionada a desfechos em saude desfavoraveis para a gestante e os recem-nascidos e, em longo prazo, a aumento de incidencia de carcinoma hepatocelular, cirrose, necessidade de transplante de figado, utilizacao de servicos de saude e mortalidade. Atualmente a conduta para a deteccao de hepatite C em gestantes depende da prospeccao de fatores de risco pre-existentes, a qual postula-se ser ineficaz na identificação do numero real de casos. O rastreamento e proposto como alternativa a testagem baseada em risco com a finalidade de aumentar a taxa de deteccao de casos, diminuir a transmissao vertical e aumentar a cobertura de tratamentos atendendo a politicas publicas de eliminacao da doenca implementadas pelo Sistema de Saude Publica brasileiro. PERGUNTA: A estrategia de rastreamento para hepatite C em gestantes no primeiro trimestre de gravidez durante o prenatal e eficaz, segura e custo-efetiva quando comparada a testagem baseada em fatores de risco de acordo com a conduta em vigencia preconizada no Protocolo Clinico e Diretrizes Terapeuticas (PCDT) de Hepatite C e Coinfeccoes do Ministerio da Saude? TECNOLOGIA: Testagem universal para hepatite C em gestantes no primeiro trimestre de gravidez durante o pre-natal. EVIDÊNCIAS CLÍNICAS: Identificou-se pela avaliacao de estudos observacionais e transversais descritivos que a estrategia de testagem baseada em risco esta associada a baixos rendimentos diagnostico e sensibilidade, ou a uma baixa deteccao de casos efetivamente diagnosticados de hepatite C em gestantes durante o pre-natal. Em estudo realizado no Canada, pais em que a prevalencia estimada de hepatite C em gestantes e de 0,6%, identificou-se que uma resposta positiva (a questionario estruturado) a pelo menos um dos fatores de risco foi relacionada com uma sensibilidade de 67%, uma especificidade de 28%, um valor preditivo positivo de 0,4% e um valor preditivo negativo de 99% para identificacao de gestantes com HCV. Alem disso, identificou-se que o valor preditivo positivo para essa estrategia e dependente dos fatores de risco avaliados. E possivel que essa variabilidade se traduza em diferentes taxas de deteccao da doenca por meio da estrategia de abordagem por risco, com numero de casos verdadeiramente positivos nao identificaveis variando amplamente entre 2,5% e 27%, mas podendo chegar a 50%. De fato, na maioria dos estudos nao se identificou associação estatisticamente significativa entre a presenca de fatores de risco e ter um diagnostico positivo para hepatite C em gestantes. Em relacao aos criterios de Wilson e Jungner, utilizados na avaliacao de estrategias de rastreamento, identificasse que a maioria deles seriam atendidos, entretanto, ainda nao ha estudos em que se avaliem desfechos em saúde relevantes de curto (de importancia obstetrica e transmissao vertical) e longo prazos (evolucao da doenca e transmissibilidade) associados a implementacao de programa de rastreamento para hepatite C em gestantes. Outro criterio nao atendido e a inexistencia atualmente de tratamento antiviral aprovado para o uso em gestantes. AVALIAÇÃO ECONÔMICA: Foi conduzida uma analise de custo-efetividade na perspectiva do Sistema Unico de Saude para comparar as duas estrategias utilizando-se um modelo estatico de arvore de decisao em combinacao com cadeias de Markov. O rastreamento foi associado a custos incrementais de R$ 288,78 e aumento incremental em anos de vida ajustados pela qualidade (AVAQ-QALY) de 0,18 por gestante rastreada em comparacao com a triagem baseada em risco, com uma razao de custo-efetividade incremental de R$1.617,95 por QALY para rastreamento versus estrategia baseada em risco. Análise de impacto orçamentário: O impacto orcamentario anual associado a implementacao de um programa de rastreamento para hepatite C em gestantes na perspectiva do Sistema Unico de Saude foi de R$ 49 milhoes, com estimativa de gastos de 250 milhoes em cinco anos. Foram considerados os gastos diretos com diagnosticos, exames e procedimentos medicos complementares e tratamento. A variacao de parametros como a taxa de cobertura de gestantes testadas no sistema publico de saude em relacao as testadas no sistema suplementar, a taxa de gestantes testadas no primeiro trimestre de gravidez, o numero de gestantes coinfectadas com HIV e a taxa de oferta de tratamento causam reducoes no impacto orcamentario que variam entre 41 e 55%. RECOMENDAÇÕES INTERNACIONAIS: As Agencias inglesa National Institute for Health and Care Excellence (NICE), a canadense Canadian Agency for Drugs and Technologies in Health (CADTH) e a European Association for the Study of the Liver recomendam a testagem baseada na deteccao de fatores de risco. Nos Estados Unidos o Centers for Disease Control and Prevention (CDC), o U.S. Preventive Services Task Force (USPSTF) e a American Association for the Study of Liver Diseases e a Infectious Diseases Society of America recomendam o rastreamento para hepatite C em gestantes. O American College of Obstetricians and Gynecologists (ACOG) esta atualmente revisando as recomendacoes publicadas em 2017. Na Australia e Nova Zelandia, em documento de 2020, o The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) recomenda o rastreamento para hepatite C em gestantes. CONSIDERAÇÕES FINAIS: Ha evidencia de moderada qualidade que a estrategia de selecao para testagem de gestantes baseada na identificacao de risco e ineficaz, com baixo valor preditivo positivo e baixa sensibilidade. Apesar de não existem estudos controlados randomizados ou estudos observacionais com braco comparador em que se avaliem as consequencias em saude e os riscos associados a ambas as estrategias, e possivel que o numero de mulheres não detectadas pela estrategia baseada em risco seja significativo com consequencias deleterias para a saude das gestantes e recem-nascidos. Na perspectiva do Sistema Unico de Saude a estrategia de rastreamento se demonstrou mais efetiva que a deteccao baseada em risco com um acrescimo de R$ 288 por gestante testada. Algumas autoridades de saude mundiais vem reformulando as recomendacoes a respeito do diagnostico da hepatite C em gestantes para indicar o rastreamento, principalmente frente ao aumento da taxa de deteccao dos casos mundiais em mulheres, como ocorre no Brasil. A implementacao do programa de rastreamento atende a maioria dos criterios de Wilson e Jungner, exceto a possibilidade de tratamento, que ainda nao e possivel em gestantes. A adocao do rastreamento estaria associada a um incremento de 49 milhoes por ano no orcamento do Ministerio da Saude, principalmente em funcao do alto custo dos tratamentos. RECOMENDAÇÃO INICIAL DA CONITEC: Os membros presentes na 87a reuniao ordinaria da Conitec, que ocorreu no dia 03/06/2020, decidiram, por unanimidade, recomendar a incorporacao da testagem universal para hepatite C em gestantes no pre-natal. CONSULTA PÚBLICA: A consulta publica n° 19/2020, publicada no Diario Oficial da Uniao de 15/06/2020, foi realizada entre os dias 16/06/2020 e 06/07/2020. Foram recebidas 50 contribuicoes, sendo 8 pelo formulario para contribuicoes tecnicocientificas e 42 pelo formulario para contribuicoes sobre experiencia ou opiniao. Entre as 8 contribuicoes recebidas e avaliadas de cunho tecnico-cientifico, 4 foram consideradas para inclusao nesse parecer, todas concordantes com a recomendacao inicial da Conitec. Houve duas contribuicoes de pessoa juridica, da Iniciativa Medicamentos Doenças Negligenciadas (DNDi America Latina) e da Sociedade Brasileira de Infectologia. Os estudos submetidos reforcam a importancia da deteccao acurada de gestantes infectadas pela hepatite C em funcao dos piores desfechos relacionados a gestação nesse contexto e clinico e da possibilidade de encaminhamento das mulheres para acompanhamento para gestação de alto risco, do melhor planejamento de procedimentos obstetricos, de tratamento das mulheres e crianças em momento oportuno apos o parto e do alinhamento com as metas para a eliminacao da doenca no pais, diminuindo a transmissao vertical. Considerou-se a abordagem de testagem por risco como ineficaz. Todas as 42 contribuições recebidas sobre experiencia com a tecnologia ou opiniao sobre a incorporacao traziam contribuicoes em algum dos campos do formulario disponivel para submissao e foram concordantes com a recomendacao inicial da Conitec, incluindo as submetidas pelo Grupo Otimismo de Apoio ao Portador de Hepatite e da Sociedade Brasileira de Hepatologia observando-se grande convergencia entre o conteudo dessas contribuicoes e as de cunho tecnico-cientifico. Apos avaliacao das contribuicoes a Conitec manteve a recomendacao inicial favoravel a incorporacao da testagem universal para hepatite C em gestantes no pre-natal. DECISÃO: Incorporar a testagem universal para hepatite viral C em gestantes no prenatal, conforme protocolo do Ministerio da Saude, no ambito do Sistema Unico de Saude - SUS, conforme Portaria no 32, publicada no Diario Oficial da Uniao no 160, secao 1, pagina 118, em 20 de agosto de 2020.

Drastic Reduction of Turnaround Time After Implementation of a Fully Automated Assay for RAS-BRAF Mutations in Colorectal Cancer: A Pilot Prospective Study in Real-life Conditions.

In some situations, there is a need for rapid mutation tests for guiding clinical decisions and starting targeted therapies with minimal delays. In this study we evaluated the turnaround time before and after the implementation of a fully automated multiplex assay for KRAS and NRAS/BRAF mutation tests (Idylla™ platform, Biocartis) in metastatic colorectal cancer. The objective of this project was to compare the turnaround times in 2017-2018 with the fully automated multiplex assay to the 2016 results with previous methods. Centers with a number of tests for metastatic colorectal cancer > 100 yearly and a usual turnaround time ≥ 3 weeks for mutation detection were selected. Results of 505 KRAS tests and 369 NRAS/BRAF tests were transmitted by 10 centers. The mean turnaround time from test prescription to reception of results was reduced from 25.8 days in 2016 to 4.5 days in 2017-2018. In conclusion, this pilot project shows that the Idylla™ platform for testing KRAS and NRAS/BRAF mutations allows an optimized turnaround time from test prescription to reception of results.

Analysis of model-based and model-free CEST effect quantification methods for different medical applications.

Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) holds great potential to provide new metabolic information for clinical applications such as tumor, stroke and Parkinson's Disease diagnosis. Many active research and developments have been conducted to translate this emerging MRI technique for routine clinical applications. In general, there are two CEST quantification techniques: (i) model-free and (ii) model-based techniques. The reliability of these quantification techniques depends heavily on the experimental conditions and quality of the collected data. Errors such as noise may lead to misleading quantification results and thus inaccurate diagnosis when CEST imaging becomes a standard or routine imaging scan in the future. This paper investigates the accuracy and robustness of these quantification techniques under different signal-to-noise (SNR) levels and magnetic field strengths. The quantified CEST effect before and after adding random Gaussian White Noise using model-free and model-based quantification techniques were compared. It was found that the model-free technique consistently yielded larger average percentage error across all tested parameters compared to its model-based counterpart, and that the model-based technique could withstand SNR of about 3 times lower than the model-free technique. When applied on noisy brain tumor, ischemic stroke, and Parkinson's Disease clinical data, the model-free technique failed to produce significant differences between normal and abnormal tissue whereas the model-based technique consistently generated significant differences. Although the model-free technique was less accurate and robust, its simplicity and thus speed would still make it a good approximate when the SNR was high (>50) or when the CEST effect was large and well-defined. For more accurate CEST quantification, model-based techniques should be considered. When SNR was low (<50) and the CEST effect was small such as those acquired from clinical field strength scanners, which are generally 3T and below, model-based techniques should be considered over model-free counterpart to maintain an average percentage error of less than 44% even under very noisy condition as tested in this work.

Application of Microfluidics in Molecular Diagnostics / 中国医疗器械杂志

In recent years, molecular diagnostics has been the most promising branch of

The Journal of Molecular Diagnostics: 20 Years of Clinical Innovation.

This guest editorial highlights 20 years of clinical innovation in JMD.

Development of a DNA isolation device using poly(3,4-dihydroxy-L-phenylalanine)-coated swab for on-site molecular diagnostics.

For on-site molecular diagnostics, a pre-treatment step for isolation of nucleic acid from clinical samples on site is desired. However, conventional commercialized silica-based nucleic acid isolation kits require repetitive pipetting and a centrifugation or permanent magnet for buffer exchange. In this study, we developed a poly(3,4-dihydroxy-L-phenylalanine) (L-DOPA)-coated swab that can absorb and desorb DNA depending on pH of buffers and a portable integrated DNA isolation device that comprises integrated chambers containing DNA isolation buffers. The poly(L-DOPA)-coated swab interacts with each buffer by passing through the membrane between the integrated chambers. Our device involves a simple operation and does not require any large equipment or skilled experts. By connecting the device with an automated polymerase chain reaction system, an isothermal amplification system, or a non-amplified DNA detection method, on-site molecular diagnosis of various diseases can be quickly realized.

A portable nucleic acid detection system using natural convection combined with a smartphone.

The development of portable nucleic acid diagnostic devices has the potential to expand the availability of molecular diagnostics into low-resource settings. One of the promising solutions for rapid and simple DNA amplification is the use of Rayleigh-Bernard natural convection which is caused by a buoyancy-driven thermal gradient of liquid when heated from below. This natural convection avoids the use of the complex and sophisticated hardware that is required for precise maintenance of temperature cycles in conventional PCR. We have developed a stand-alone convective PCR (cPCR) device linked to a smartphone for rapid detection of nucleic acids using natural convection heating. The device amplifies multiple DNA samples simultaneously using a custom-made heat block controlled by Bluetooth wireless communication. The entire device is highly portable, user-friendly, battery-operated and can provide target DNA amplification in less than 30 min. A detection limit of 2.8 × 103 copies of a segment of lambda DNA was obtained when the two different fluorescently-tagged amplicons were collected magnetically and detected using the smartphone fluorescence reader. Thus, the combination of cPCR and multiplex fluorescence-based detection on a smartphone provides new opportunities for the development of affordable and portable molecular diagnostic devices for point-of-care situations or remote clinical settings.

3D Printed Modular Immunofiltration Columns for Frequency Mixing-Based Multiplex Magnetic Immunodetection.

For performing point-of-care molecular diagnostics, magnetic immunoassays constitute a promising alternative to established enzyme-linked immunosorbent assays (ELISA) because they are fast, robust and sensitive. Simultaneous detection of multiple biomolecular targets from one body fluid sample is desired. The aim of this work is to show that multiplex magnetic immunodetection based on magnetic frequency mixing by means of modular immunofiltration columns prepared for different targets is feasible. By calculations of the magnetic response signal, the required spacing between the modules was determined. Immunofiltration columns were manufactured by 3D printing and antibody immobilization was performed in a batch approach. It was shown experimentally that two different target molecules in a sample solution could be individually detected in a single assaying step with magnetic measurements of the corresponding immobilization filters. The arrangement order of the filters and of a negative control did not influence the results. Thus, a simple and reliable approach to multi-target magnetic immunodetection was demonstrated.

Novel applications of array comparative genomic hybridization in molecular diagnostics.

INTRODUCTION: In 2004, the implementation of array comparative genomic hybridization (array comparative genome hybridization [CGH]) into clinical practice marked a new milestone for genetic diagnosis. Array CGH and single-nucleotide polymorphism (SNP) arrays enable genome-wide detection of copy number changes in a high resolution, and therefore microarray has been recognized as the first-tier test for patients with intellectual disability or multiple congenital anomalies, and has also been applied prenatally for detection of clinically relevant copy number variations in the fetus. Area covered: In this review, the authors summarize the evolution of array CGH technology from their diagnostic laboratory, highlighting exonic SNP arrays developed in the past decade which detect small intragenic copy number changes as well as large DNA segments for the region of heterozygosity. The applications of array CGH to human diseases with different modes of inheritance with the emphasis on autosomal recessive disorders are discussed. Expert commentary: An exonic array is a powerful and most efficient clinical tool in detecting genome wide small copy number variants in both dominant and recessive disorders. However, whole-genome sequencing may become the single integrated platform for detection of copy number changes, single-nucleotide changes as well as balanced chromosomal rearrangements in the near future.

Entering the Pantheon of 21st Century Molecular Biology Tools: A Perspective on Digital PCR.

After several decades of relatively modest use, in the last several years digital PCR (dPCR) has grown to become the new gold standard for nucleic acid quantification. This coincides with the commercial availability of scalable, affordable, and reproducible droplet-based dPCR platforms in the past five years and has led to its rapid dissemination into diverse research fields and testing applications. Among these, it has been adopted most vigorously into clinical oncology where it is beginning to be used for plasma genotyping in cancer patients undergoing treatment. Additionally, innovation across the scientific community has extended the benefits of reaction partitioning beyond DNA and RNA quantification alone, and demonstrated its usefulness in evaluating DNA size and integrity, the physical linkage of colocalized markers, levels of enzyme activity and specific cation concentrations in a sample, and more. As dPCR technology gains in popularity and breadth, its power and simplicity can often be taken for granted; thus, the reader is reminded that due diligence must be exercised in order to make claims not only of precision but also of accuracy in their measurements.

Basic Concepts and Validation of Digital PCR Measurements.

Use of digital polymerase chain reaction (dPCR) technology is rapidly growing and diversifying into a range of areas in life science. The release of dPCR commercial systems has facilitated access, leading to recognition of the potential advantages compared to previous quantitative PCR technologies, and the scope for novel applications. The capability of dPCR to deliver unprecedented levels of precision, accuracy, and resolution in quantification of nucleic acids has triggered a strong interest by academia and the life sciences industry in use of this technology as a molecular diagnostic tool. However, the performance of dPCR, as for a "classical" PCR assay, essentially still relies on enzyme-based amplification of nucleic acid using specific reagents and instrumentation. This chapter describes basic concepts, key properties, and important factors to consider for the verification and validation of dPCR measurements.

A review of novel technologies and techniques associated with identification of bloodstream infection etiologies and rapid antimicrobial genotypic and quantitative phenotypic determination.

INTRODUCTION: The antimicrobial aspect of management of patients with blood stream infections (BSI) and sepsis is time critical. In an era of increasing antimicrobial resistance, rapid detection and identification of bacteria with antimicrobial susceptibility is crucial to direct therapy early in the course of illness. Molecular techniques offer a potential solution to this. Areas covered: In the present review the authors have discussed a number of novel solutions utilizing a variety of molecular techniques for pathogen detection, identification and antimicrobial susceptibility. The review is not designed to be an exhaustive literature review covering all diagnostic solutions ever developed, instead the authors have focused on what they have had experience using, evaluating or currently view as new and exciting with potential to revolutionize BSI diagnosis. The authors searched PubMed (Medline) and Google Scholar with terms: BSI, Bacteraemia, Candidaemia, Diagnostics, AST, Rapid, AMR, Novel and Blood Culture. The authors attended recent clinical microbiology technology congresses. Expert commentary: There are multiple exciting novel technologies at differing stages of development with potential to revolutionize diagnosis of BSI. More work is needed as well as a standardized assessment of different platforms in order to better understand the clinical and financial impacts these will have in clinical microbiology laboratories.

Development of a rapid field-applicable molecular diagnostic for knockdown resistance (kdr) markers in An. gambiae.

BACKGROUND: The spread of insecticide resistance (IR) is a major threat to vector control programmes for mosquito-borne diseases. Early detection of IR using diagnostic markers could help inform these programmes, especially in remote locations where gathering reliable bioassay data is challenging. Most current molecular tests for genetic IR markers are only suitable for use in well-equipped laboratory settings. There is an unmet need for field-applicable diagnostics. METHODS: A single-cartridge test was designed to detect key IR mutations in the major African vector of malaria, Anopheles gambiae. Developed on the portable, rapid, point-of-care compatible PCR platform - Genedrive® (genedrive® plc), the test comprises two assays which target single nucleotide polymorphisms (SNPs) in the voltage gated sodium channel (VGSC) gene that exert interactive effects on knockdown resistance (kdr): L1014F, L1014S and N1575Y. RESULTS: Distinct melt peaks were observed for each allele at each locus. Preliminary validation of these assays using a test panel of 70 An. gambiae samples showed complete agreement of our assays with the widely-used TaqMan assays, achieving a sensitivity and specificity of 100%. CONCLUSION: Here we show the development of an insecticide resistance detection assay for use on the Genedrive® platform that has the potential to be the first field-applicable diagnostic for kdr.