Reverse Transcription Loop-Mediated Isothermal Amplification Assay for Ultrasensitive Detection of SARS-CoV-2 in Saliva and Viral Transport Medium Clinical Samples

Construction of AlGaN/GaN high-electron-mobility transistor-based biosensor for ultrasensitive detection of SARS-CoV-2 spike proteins and virions

The COVID-19 pandemic has highlighted the need for rapid and sensitive detection of SARS-CoV-2. Here, we report an ultrasensitive SARS-CoV-2 immunosensor by integration of an AlGaN/GaN high-electron-mobility transistor (HEMT) and anti-SARS-CoV-2 spike protein antibody. The AlGaN/GaN HEMT immunosensor has demonstrated the capability to detect SARS-CoV-2 spike proteins at an impressively low concentration of 10-22 M. The sensor was also applied to pseudoviruses and SARS-CoV-2 ΔN virions that display the Spike proteins with a single virion particle sensitivity. These features validate the potential of AlGaN/GaN HEMT biosensors for point of care tests targeting SARS-CoV-2. This research not only provides the first HEMT biosensing platform for ultrasensitive and label-free detection of SARS-CoV-2.

Point-of-care isothermal nucleic acid amplification tests: progress and bottlenecks for extraction-free sample collection and preparation

INTRODUCTION

Suitable sample collection and preparation methods are essential to enable nucleic acid amplification testing at the point of care (POC). Strategies that allow direct isothermal nucleic acid amplification testing (iNAAT) of crude sample lysate without the need for nucleic acid extraction minimize time to result as well as the need for operator expertise and costly infrastructure.

AREAS COVERED

The authors review research to understand how sample matrix and preparation affect the design and performance of POC iNAATs. They focus on approaches where samples are directly combined with liquid reagents for preparation and amplification via iNAAT strategies. They review factors related to the type and method of sample collection, storage buffers, and lysis strategies. Finally, they discuss RNA targets and relevant regulatory considerations.

EXPERT OPINION

Limitations in sample preparation methods are a significant technical barrier preventing implementation of nucleic acid testing at the POC. The authors propose a framework for co-designing sample preparation and amplification steps for optimal performance with an extraction-free paradigm by considering a sample matrix and lytic strategy prior to an amplification assay and readout. In the next 5 years, the authors anticipate increasing priority on the co-design of sample preparation and iNAATs.

Accurate and reliable surface-enhanced Raman spectroscopy assay for early detection of SARS-CoV-2 RNA with exceptional sensitivity

This research proposes a highly sensitive and simple surface-enhanced Raman spectroscopy (SERS) assay for the detection of SARS-CoV-2 RNA using suitably designed probes specific for RdRp and N viral genes attached to a Raman marker. The sensitivity of the assay was optimized through precise adjustments to the conditions of immobilization and hybridization processes of the target RNA, including modifications to factors such as time and temperature. The assay achieved a remarkable sensitivity down to 58.39 copies/mL, comparable to or lower than the sensitivities reported for commercial fluorescent polymerase chain reaction (PCR) based methods. It has good selectivity in discriminating SARS-CoV-2 RNA against other respiratory viruses, respiratory syncytial virus (RSV), and influenza A virus. The reliability of the assay was validated by testing 24 clinical samples, including 12 positive samples with varying cycle threshold (Ct) values and 12 negative samples previously tested using real-time PCR. The assay consistently predicted true results that were in line with the PCR results for all samples. Furthermore, the assay demonstrated a notable limit of detection (LOD) of Ct (38 for RdRp gene and 37.5 for N-gene), indicating its capability to detect low concentrations of the target analyte and potentially facilitating early detection of the pathogen.

Smartphone-based device for point-of-care diagnostics of pulmonary inflammation using convolutional neural networks (CNNs)

In pulmonary inflammation diseases, like COVID-19, lung involvement and inflammation determine the treatment regime. Respiratory inflammation is typically arisen due to the cytokine storm and the leakage of the vessels for immune cells recruitment. Currently, such a situation is detected by the clinical judgment of a specialist or precisely by a chest CT scan. However, the lack of accessibility to the CT machines in many poor medical centers as well as its expensive service, demands more accessible methods for fast and cheap detection of lung inflammation. Here, we have introduced a novel method for tracing the inflammation and lung involvement in patients with pulmonary inflammation, such as COVID-19, by a simple electrolyte detection in their sputum samples. The presence of the electrolyte in the sputum sample results in the fern-like structures after air-drying. These fern patterns are different in the CT positive and negative cases that are detected by an AI application on a smartphone and using a low-cost and portable mini-microscope. Evaluating 160 patient-derived sputum sample images, this method demonstrated an interesting accuracy of 95%, as confirmed by CT-scan results. This finding suggests that the method has the potential to serve as a promising and reliable approach for recognizing lung inflammatory diseases, such as COVID-19.

Nanozyme-Based Colorimetric SARS-CoV-2 Nucleic Acid Detection by Naked Eye

Fluorescence-based PCR and other amplification methods have been used for SARS-CoV-2 diagnostics, however, it requires costly fluorescence detectors and probes limiting deploying large-scale screening. Here, a cut-price colorimetric method for SARS-CoV-2 RNA detection by iron manganese silicate nanozyme (IMSN) is established. IMSN catalyzes the oxidation of chromogenic substrates by its peroxidase (POD)-like activity, which is effectively inhibited by pyrophosphate ions (PPi). Due to the large number of PPi generated by amplification processes, SARS-CoV-2 RNA can be detected by a colorimetric readout visible to the naked eye, with the detection limit of 240 copies mL^-1 . This conceptually new method has been successfully applied to correctly distinguish positive and negative oropharyngeal swab samples of COVID-19. Colorimetric assay provides a low-cost and instrumental-free solution for nucleic acid detection, which holds great potential for facilitating virus surveillance.

Dual-Gene-Controlled Rolling Circle Amplification Strategy for SARS-CoV-2 Analysis

The development of sensitive, accurate, and conveniently operated methods for the simultaneous assay of two nucleic acids is promising while still challenging. In this work, by using two genes (the N gene and RdRp gene) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as examples, we have designed an ingenious dual-gene-controlled rolling circle amplification (RCA) strategy to propose an accurate and sensitive electrochemical method. Specifically, the coexistence of the two target genes can trigger the RCA reaction to generate a number of repeated G-quadruplex (G4)-forming sequences. These sequences then switch into G4/hemin complexes with redox activity after the incubation of hemin, which can catalyze the TMB/H2O2 substrates to produce significantly enhanced current responses. Experimental results reveal that the proposed method exhibits satisfying feasibility and analytical performance, enabling the sensitive detection of SARS-CoV-2 in the range of 0.1-5000 pM, with the detection limit of 57 fM. Meanwhile, because only the simultaneous existence of the two target genes can effectively trigger the downstream amplification reaction, this method can effectively avoid false-positives and ensure specificity as well as accuracy. Furthermore, our method can distinguish the COVID-19 samples from healthy people, and the outcomes show a satisfying agreement with the results of RT-PCR, manifesting that our label-free dual-gene-controlled RCA strategy exhibits great possibility in clinical application.

Colorimetric Detection of the SARS-CoV-2 Virus (COVID-19) in Artificial Saliva Using Polydiacetylene Paper Strips

The spread and resurgence of the SARS-CoV-2 virus (COVID-19 disease) threatens human health and social relations. Prevention of COVID-19 disease partly relies on fabricating low-cost, point-of-care (POC) sensing technology that can rapidly and selectively detect the SARS-CoV-2 virus. We report a colorimetric, paper-based polydiacetylene (PDA) biosensor, designed to detect SARS-CoV-2 spike protein in artificial saliva. Analytical characterizations of the PDA sensor using NMR and FT-IR spectroscopy showed the correct structural elucidation of PCDA-NHS conjugation. The PDA sensor platform containing the N-Hydroxysuccinimide ester of 10, 12-pentacosadiynoic acid (PCDA-NHS) was divided into three experimental PCDA-NHS concentration groups of 10%, 20%, and 30% to optimize the performance of the sensor. The optimal PCDA-NHS molar concentration was determined to be 10%. The PDA sensor works by a color change from blue to red as its colorimetric output when the immobilized antibody binds to the SARS-CoV-2 spike protein in saliva samples. Our results showed that the PDA sensing platform was able to rapidly and qualitatively detect the SARS-CoV-2 spike protein within the concentration range of 1 to 100 ng/mL after four hours of incubation. Further investigation of pH and temperature showed minimal influence on the PDA sensor for the detection of COVID-19 disease. After exposure to the SARS-CoV-2 spike protein, smartphone images of the PDA sensor were used to assess the sensor output by using the red chromatic shift (RCS) of the signal response. These results indicate the potential and practical use of this PDA sensor design for the rapid, colorimetric detection of COVID-19 disease in developing countries with limited access to medical testing.

Toward a Home Test for COVID 19 Diagnosis: DNA Machine for Amplification-Free SARS-CoV-2 Detection in Clinical Samples

Nucleic acid-based detection of RNA viruses requires annealing procedure to obtain RNA/probe or RNA/primer complexes for unwinding stable structure of folded viral RNA. In this study, we designed a protein enzymes-free nano-construction, names four-armed DNA machine (4DNM), that requires neither amplification stage nor high temperature annealing step for SARS-CoV-2 detection. It uses binary deoxyribozyme (BiDz) sensor incorporated in a DNA nanostructure equipped with total of four RNA-binding arms. Additional arms improved limit of detection at least 10 times. The sensor distinguished SARS-CoV-2 from other respiratory viruses and correctly identified five positive and six negative clinical samples verified by quantitative polymerase chain reaction (RT-qPCR). The strategy reported here can be used for detection of long natural RNA and can become a basis for a point-of-care or home diagnostic test.

Smartphone clip-on instrument and microfluidic processor for rapid sample-to-answer detection of Zika virus in whole blood using spatial RT-LAMP

Rapid, simple, inexpensive, accurate, and sensitive point-of-care (POC) detection of viral pathogens in bodily fluids is a vital component of controlling the spread of infectious diseases. The predominant laboratory-based methods for sample processing and nucleic acid detection face limitations that prevent them from gaining wide adoption for POC applications in low-resource settings and self-testing scenarios. Here, we report the design and characterization of an integrated system for rapid sample-to-answer detection of a viral pathogen in a droplet of whole blood comprised of a 2-stage microfluidic cartridge for sample processing and nucleic acid amplification, and a clip-on detection instrument that interfaces with the image sensor of a smartphone. The cartridge is designed to release viral RNA from Zika virus in whole blood using chemical lysis, followed by mixing with the assay buffer for performing reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP) reactions in six parallel microfluidic compartments. The battery-powered handheld detection instrument uniformly heats the compartments from below, and an array of LEDs illuminates from above, while the generation of fluorescent reporters in the compartments is kinetically monitored by collecting a series of smartphone images. We characterize the assay time and detection limits for detecting Zika RNA and gamma ray-deactivated Zika virus spiked into buffer and whole blood and compare the performance of the same assay when conducted in conventional PCR tubes. Our approach for kinetic monitoring of the fluorescence-generating process in the microfluidic compartments enables spatial analysis of early fluorescent "bloom" events for positive samples, in an approach called "Spatial LAMP" (S-LAMP). We show that S-LAMP image analysis reduces the time required to designate an assay as a positive test, compared to conventional analysis of the average fluorescent intensity of the entire compartment. S-LAMP enables the RT-LAMP process to be as short as 22 minutes, resulting in a total sample-to-answer time in the range of 17-32 minutes to distinguish positive from negative samples, while demonstrating a viral RNA detection as low as 2.70 × 102 copies per μl, and a gamma-irradiated virus of 103 virus particles in a single 12.5 μl droplet blood sample.

Evaluating Saliva Sampling with Reverse Transcription Loop-mediated Isothermal Amplification to Improve Access to SARS-CoV-2 Diagnosis in Low-Resource Settings

Standard diagnosis of SARS-CoV-2 by nasopharyngeal swab (NPS) and real-time reverse transcriptase-polymerase chain reaction (PCR) requires a sophisticated laboratory, skilled staff, and expensive reagents that are difficult to establish and maintain in isolated, low-resource settings. In the remote setting of tropical Sumba Island, eastern Indonesia, we evaluated alternative sampling with fresh saliva (FS) and testing with colorimetric loop-medicated isothermal amplification (LAMP). Between August 2020 and May 2021, we enrolled 159 patients with suspected SARS-CoV-2 infection, of whom 75 (47%) had a positive PCR on NPS (median cycle threshold [Ct] value: 27.6, interquartile range: 12.5-37.6). PCR on FS had a sensitivity of 72.5% (50/69, 95% confidence interval [CI]: 60.4-82.5) and a specificity of 85.7% (66/77, 95% CI: 75.9-92.6), and positive (PPV) and negative (NPV) predictive values of 82.0% (95% CI: 0.0-90.6) and 77.6% (95% CI: 67.3-86.0), respectively. LAMP on NPS had a sensitivity of 68.0% (51/75, 95% CI: 56.2-78.3) and a specificity of 70.8% (63/84, 95% CI: 58.9-81.0), with PPV 70.8% (95% CI: 58.9-81.0) and NPV 72.4% (95% CI: 61.8-81.5%). LAMP on FS had a sensitivity of 62.3% (43/69, 95% CI: 49.8-73.7%) and a specificity of 72.7% (56/77, 95% CI: 61.4-82.3%), with PPV 67.2% (95% CI: 54.3-78.4) and NPV 68.3% (95% CI: 57.1-78.1%). LAMP sensitivity was higher for NPS and FS specimens with high viral loads (87.1% and 75.0% for Ct value < 26, respectively). Dried saliva on filter paper was stable for 4 days at room temperature. LAMP on either NPS or FS could offer an accessible alternative for SARS-CoV-2 diagnosis in low-resource settings, with potential for optimizing sample collection and processing, and selection of gene targets.

Rotational diffusometric sensor with isothermal amplification for ultra-sensitive and rapid detection of SARS-CoV-2 nsp2 cDNA

In the wake of a pandemic, the development of rapid, simple, and accurate molecular diagnostic tests can significantly aid in reducing the spread of infections. By combining particle imaging with molecular assays, a quick and highly sensitive biosensor can readily identify a pathogen at low concentrations. Here, we implement functionalized particle-enabled rotational diffusometry in combination with loop-mediated isothermal amplification for the rapid detection of the SARS-CoV-2 nsp2 gene in the recombinant plasmid as a proof of concept for COVID-19 diagnostics. By analyzing the images of blinking signals generated by these modified particles, the change in micro-level viscosity due to nucleic acid amplification was measured. The high sensitivity of rotational diffusometry enabled facile detection within 10 min, with a limit of detection of 70 ag/μL and a sample volume of 2 μL. Tenfold higher detection sensitivity was observed for rotational diffusometry in comparison with real-time PCR. In addition, the system stability and the effect of temperature on rotational diffusometric measurements were studied and reported. These results demonstrated the utility of a rotational diffusometric platform for the rapid and sensitive detection of SARS-CoV-2 cDNA fragments.

Strategies for Scaling up SARS-CoV-2 Molecular Testing Capacity

Scaling up SARS-CoV-2 testing during the COVID-19 pandemic was critical to maintaining clinical operations and an open society. Pooled testing and automation were two critical strategies used by laboratories to meet the unprecedented demand. Here, we review these and other cutting-edge strategies that sought to expand SARS-CoV-2 testing capacity while maintaining high individual test performance.

Saliva as a diagnostic specimen for SARS-CoV-2 detection: a scoping review

Objectives

This scoping review aims to summarize the diagnostic value of saliva assessed from current studies that (1) compare its performance in reverse transcriptase‐polymerase chain reaction testing to nasopharyngeal swabs, (2) evaluate its performance in rapid and point‐of‐care COVID‐19 diagnostic tests, and (3) explore its use as a specimen for detecting anti‐SARS‐CoV‐2 antibodies.

Materials and Methods

A systematic search was performed on the following databases: Medline and Embase (Ovid), World Health Organization, Centers for Disease Control and Prevention, and Global Health (Ovid) from January 2019 to September 2021. Of the 657 publications identified from the searches, n = 146 articles were included in the final scoping review.

Results

Our findings showcase that salivary samples exceed nasopharyngeal swabs in detecting SARS‐CoV‐2 using reverse transcriptase‐polymerase chain reaction testing in several studies. A select number of rapid antigen and point‐of‐care tests from the literature were also identified capable of high detection rates using saliva. Moreover, anti‐SARS‐CoV‐2 antibodies have been shown to be detectable in saliva through biochemical assays.

Conclusion

We highlight the potential of saliva as an all‐rounded specimen in detecting SARS‐CoV‐2. However, future large‐scale clinical studies will be needed to support its widespread use as a non‐invasive clinical specimen for COVID‐19 testing.

Dual-site ligation-assisted loop-mediated isothermal amplification (dLig-LAMP) for colorimetric and point-of-care determination of real SARS-CoV-2

A probing system has been developed based on dual-site ligation-assisted loop-mediated isothermal amplification (dLig-LAMP) for the selective colorimetric detection of SARS-CoV-2. This approach can induce false-positive and -negative detection in real clinical samples; dLig-LAMP operates with improved selectivity. Unlike RT-LAMP, the selectivity of dLig-LAMP is determined in both the ligation and primer binding steps, not in the reverse transcription step. With this selective system in hand, we developed a colorimetric signaling system for point-of-care detection. We also developed a colorimetric probe for sensing pyrophosphate, which arises as a side product during the LAMP DNA amplification. Thus, dLig-LAMP appears to be an alternative method for improving the selectivity problems associated with reverse transcription. In addition, combining dLig-LAMP with colorimetric pyrophosphate probing allows point-of-care detection of SARS-CoV-2 within 1 h with high selectivity.

Microfluidic point-of-care device for detection of early strains and B.1.1.7 variant of SARS-CoV-2 virus

Since the beginning of the COVID-19 pandemic, several mutations of the SARS-CoV-2 virus have emerged. Current gold standard detection methods for detecting the virus and its variants are based on PCR-based diagnostics using complex laboratory protocols and time-consuming steps, such as RNA isolation and purification, and thermal cycling. These steps limit the translation of technology to the point-of-care and limit accessibility to under-resourced regions. While PCR-based assays currently offer the possibility of multiplexed gene detection, and commercial products of single gene PCR and isothermal LAMP at point-of-care are also now available, reports of isothermal assays at the point-of-care with detection of multiple genes are lacking. Here, we present a microfluidic assay and device to detect and differentiate the Alpha variant (B.1.1.7) from the SARS-CoV-2 virus early strains in saliva samples. The detection assay, which is based on isothermal RT-LAMP amplification, takes advantage of the S-gene target failure (SGTF) to differentiate the Alpha variant from the SARS-CoV-2 virus early strains using a binary detection system based on spatial separation of the primers specific to the N- and S-genes. We use additively manufactured plastic cartridges in a low-cost optical reader system to successfully detect the SARS-CoV-2 virus from saliva samples (positive amplification is detected with concentration ≥10 copies per μL) within 30 min. We demonstrate that our platform can discriminate the B.1.1.7 variant (USA/CA_CDC_5574/2020 isolate) from SARS-CoV-2 negative samples, but also from the SARS-CoV-2 USA-WA1/2020 isolate. The reliability of the developed point-of-care device was confirmed by testing 38 clinical saliva samples, including 20 samples positive for Alpha variant (sensitivity > 90%, specificity = 100%). This study highlights the current relevance of binary-based testing, as the new Omicron variant also exhibits S-gene target failure and could be tested by adapting the approach presented here.

Overcoming the limitations of COVID-19 diagnostics with nanostructures, nucleic acid engineering, and additive manufacturing

The COVID-19 pandemic revealed fundamental limitations in the current model for infectious disease diagnosis and serology, based upon complex assay workflows, laboratory-based instrumentation, and expensive materials for managing samples and reagents. The lengthy time delays required to obtain test results, the high cost of gold-standard PCR tests, and poor sensitivity of rapid point-of-care tests contributed directly to society's inability to efficiently identify COVID-19-positive individuals for quarantine, which in turn continues to impact return to normal activities throughout the economy. Over the past year, enormous resources have been invested to develop more effective rapid tests and laboratory tests with greater throughput, yet the vast majority of engineering and chemistry approaches are merely incremental improvements to existing methods for nucleic acid amplification, lateral flow test strips, and enzymatic amplification assays for protein-based biomarkers. Meanwhile, widespread commercial availability of new test kits continues to be hampered by the cost and time required to develop single-use disposable microfluidic plastic cartridges manufactured by injection molding. Through development of novel technologies for sensitive, selective, rapid, and robust viral detection and more efficient approaches for scalable manufacturing of microfluidic devices, we can be much better prepared for future management of infectious pathogen outbreaks. Here, we describe how photonic metamaterials, graphene nanomaterials, designer DNA nanostructures, and polymers amenable to scalable additive manufacturing are being applied towards overcoming the fundamental limitations of currently dominant COVID-19 diagnostic approaches. In this paper, we review how several distinct classes of nanomaterials and nanochemistry enable simple assay workflows, high sensitivity, inexpensive instrumentation, point-of-care sample-to-answer virus diagnosis, and rapidly scaled manufacturing.

Detection of SARS-CoV-2 Virus Amplification Using a Crumpled Graphene Field-Effect Transistor Biosensor

The rapid and unexpected spread of SARS-CoV-2 worldwide has caused unprecedented disruption to daily life and has brought forward critical challenges for public health. The disease was the largest cause of death in the United States in early 2021. Likewise, the COVID-19 pandemic has highlighted the need for rapid and accurate diagnoses at scales larger than ever before. To improve the availability of current gold standard diagnostic testing methods, the development of point-of-care devices that can maintain gold standard sensitivity while reducing the cost and providing portability is much needed. In this work, we combine the amplification capabilities of reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) techniques with high-sensitivity end-point detection of crumpled graphene field-effect transistors (cgFETs) to develop a portable detection cell. This electrical detection method takes advantage of the ability of graphene to adsorb single-stranded DNA due to noncovalent π-π bonds but not double-stranded DNA. These devices have demonstrated the ability to detect the presence of the SARS-CoV-2 virus in a range from 10 to 104 copies/μL in 20 viral transport medium (VTM) clinical samples. As a result, we achieved 100% PPV, NPV, sensitivity, and specificity with 10 positive and 10 negative VTM clinical samples. Further, the cgFET devices can differentiate between positive and negative VTM clinical samples in 35 min based on the Dirac point shift. Likewise, the improved sensing capabilities of the crumpled gFET were compared with those of the traditional flat gFET devices.

Point-of-Care Diagnostic Tools for Surveillance of SARS-CoV-2 Infections

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a recently emerged and highly contagious virus that causes coronavirus disease 2019 (COVID-19). As of August 24, 2021, there were more than 212 million confirmed COVID-19 cases and nearly 4.4 million deaths reported globally. Early diagnosis and isolation of infected individuals remains one of the most effective public health interventions to control SARS-CoV-2 spread and for effective clinical management of COVID-19 cases. Currently, SARS-CoV-2 infection is diagnosed presumptively based on clinical symptoms and confirmed by detecting the viral RNA in respiratory samples using reverse transcription polymerase chain reaction (RT-PCR). Standard RT-PCR protocols are time consuming, expensive, and technically demanding, which makes them a poor choice for large scale and point-of-care screening in resource-poor settings. Recently developed isothermal nucleic acid amplification tests (iNAAT), antigen and/or serological tests are cost-effective to scale COVID-19 testing at the point-of-care (PoC) and for surveillance activities. This review discusses the development of rapid PoC molecular tools for the detection and surveillance of SARS-CoV-2 infections.

RAP: A Novel Approach to the Rapid and Highly Sensitive Detection of Respiratory Viruses

Recombinase aided amplification (RAA) is an emerging isothermal amplification method used for detecting various pathogens. However, RAA requires a complex and long probe to ensure high sensitivity during fluorescence assay. TaqMan probe used for quantitative PCR (qPCR) is simple and universal. Herein, we developed a new approach for detecting nucleic acids of pathogens, known as RAP (Recombinase aided PCR). The method combines RAA and qPCR to ensure a rapid and highly sensitive detection using a conventional qPCR device. RAP is a two-stage amplification process performed in a single tube within 1 hour. The method involves an RAA reaction for 10 min at 39°C (first stage) followed by 15 cycles of qPCR (second stage). Using human adenovirus 3 (HADV3) and human adenovirus 7 (HADV7) plasmids, the sensitivities of RAP assays for detecting HADV3 and HADV7 were 6 and 17 copies per reaction, respectively. The limit of RAP detection was at least 16-fold lower than the corresponding qPCR, and no-cross reaction with other respiratory viruses was observed. The results of RAP analysis revealed 100% consistency with qPCR assay. This study shows that RAP assay is a rapid, specific, and highly sensitive detection method with a potential for clinical and laboratory application.