scholarly journals SARS-CoV-2 antigen rapid diagnostic test enhanced with silver amplification technology

2021 ◽  
Author(s):  
Kei Miyakawa ◽  
Rikako Funabashi ◽  
Yutaro Yamaoka ◽  
Sundararaj Stanleyraj Jeremiah ◽  
Junichi Katada ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Point Of Care ◽  
Rapid Diagnosis ◽  
Clinical Samples ◽  
Nasopharyngeal Swab ◽  
Special Equipment ◽  
Viral Spread ◽  
Silver Amplification ◽  
Low Sensitivity

AbstractRapid diagnosis of COVID-19 is essential for instituting measures to prevent viral spread. SARS-CoV-2 antigen rapid diagnostic test (Ag-RDT) based on lateral flow immunochromatography assay (LFIA) principle can visually indicate the presence of SARS-CoV-2 antigens as a band. Ag-RDT is clinically promising as a point-of-care testing because it can give results in a short time without the need for special equipment. Although various antigen capture LFIAs are now available for rapid diagnosis for SARS-CoV-2 infection, they face the problems of low sensitivity. We have previously developed highly specific monoclonal antibodies (mAb) against SARS-CoV-2 nucleocapsid protein (NP) and in this study, we have employed these mAbs to develop a new LFIA that can detect SARS-CoV-2 NP in nasopharyngeal swab samples with higher sensitivity by combining them with silver amplification technology. We also compared the performance of our Ag-RDT against the commercially available Ag-RDTs using clinical samples to find that our newly developed LFIA performed best among tested, highlighting the superiority of silver amplification technology.

scholarly journals Direct diagnostic testing of SARS-CoV-2 without the need for prior RNA extraction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shan Wei ◽  
Esther Kohl ◽  
Alexandre Djandji ◽  
Stephanie Morgan ◽  
Susan Whittier ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Diagnostic Testing ◽  
Rna Extraction ◽  
Cost Effective ◽  
Clinical Samples ◽  
Nasopharyngeal Swab ◽  
Percentage Agreement ◽  
Testing Method ◽  
Viral Transport

AbstractThe COVID-19 pandemic has resulted in an urgent need for a rapid, point of care diagnostic testing that could be rapidly scaled on a worldwide level. We developed and tested a highly sensitive and robust assay based on reverse transcription loop mediated isothermal amplification (RT-LAMP) that uses readily available reagents and a simple heat block using contrived spike-in and actual clinical samples. RT-LAMP testing on RNA-spiked samples showed a limit of detection (LoD) of 2.5 copies/μl of viral transport media. RT-LAMP testing directly on clinical nasopharyngeal swab samples in viral transport media had an 85% positive percentage agreement (PPA) (17/20), and 100% negative percentage agreement (NPV) and delivered results in 30 min. Our optimized RT-LAMP based testing method is a scalable system that is sufficiently sensitive and robust to test for SARS-CoV-2 directly on clinical nasopharyngeal swab samples in viral transport media in 30 min at the point of care without the need for specialized or proprietary equipment or reagents. This cost-effective and efficient one-step testing method can be readily available for COVID-19 testing world-wide, especially in resource poor settings.

scholarly journals Performance Evaluation of Commercial Dengue Diagnostic Tests for Early Detection of Dengue in Clinical Samples

2017 ◽  
Vol 2017 ◽  
pp. 1-4 ◽  
Author(s):  
Tuan Nur Akmalina Mat Jusoh ◽  
Rafidah Hanim Shueb
Keyword(s):  
Dengue Virus ◽  
Real Time ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Dengue Infection ◽  
Clinical Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rt Pcr ◽  
Serum Samples ◽  
Kappa Agreement

The shattering rise in dengue virus infections globally has created a need for an accurate and validated rapid diagnostic test for this virus. Rapid diagnostic test (RDT) and reverse transcription-polymerase chain reaction (RT-PCR) diagnostic detection are useful tools for diagnosis of early dengue infection. We prospectively evaluated the diagnostic performance of nonstructural 1 (NS1) RDT and real-time RT-PCR diagnostic kits in 86 patient serum samples. Thirty-six samples were positive for dengue NS1 antigen while the remaining 50 were negative when tested with enzyme-linked immunosorbent assay (ELISA). Commercially available RDTs for NS1 detection, RTK ProDetect™, and SD Bioline showed high sensitivity of 94% and 89%, respectively, compared with ELISA. GenoAmp® Trioplex Real-Time RT-PCR and RealStar® Dengue RT-PCR tests presented a comparable kappa agreement with 0.722. The result obtained from GenoAmp® Real-Time RT-PCR Dengue test showed that 14 samples harbored dengue virus type 1 (DENV-1), 8 samples harbored DENV-2, 2 samples harbored DENV-3, and 1 sample harbored DENV-4. 1 sample had a double infection with DENV-1 and DENV-2. The NS1 RDTs and real-time RT-PCR tests were found to be a useful diagnostic for early and rapid diagnosis of acute dengue and an excellent surveillance tool in our battle against dengue.

scholarly journals Application of the amplification-free SERS-based CRISPR/Cas12a platform in the identification of SARS-CoV-2 from clinical samples

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jiajie Liang ◽  
Peijun Teng ◽  
Wei Xiao ◽  
Guanbo He ◽  
Qifang Song ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Point Of Care ◽  
Clinical Samples ◽  
Nasopharyngeal Swab ◽  
Enhancement Effect ◽  
Diagnostic Assays ◽  
Point Of Care Test ◽  
Raman Enhancement ◽  
Potential Strategy ◽  
Refractory Diseases

AbstractThe control of contagious or refractory diseases requires early, rapid diagnostic assays that are simple, fast, and easy-to-use. Here, easy-to-implement CRISPR/Cas12a-based diagnostic platform through Raman transducer generated by Raman enhancement effect, term as SERS-CRISPR (S-CRISPR), are described. The S-CRISPR uses high-activity noble metallic nanoscopic materials to increase the sensitivity in the detection of nucleic acids, without amplification. This amplification-free platform, which can be performed within 30–40 min of incubation time, is then used for detection of SARS-CoV-2 derived nucleic acids in RNA extracts obtained from nasopharyngeal swab specimens (n  =  112). Compared with the quantitative reverse transcription polymerase chain reaction (RT-qPCR), the sensitivity and specificity of S-CRISPR reaches 87.50% and 100%, respectively. In general, the S-CRISPR can rapidly identify the RNA of SARS-CoV-2 RNA without amplification and is a potential strategy for nucleic acid point of care test (POCT).

scholarly journals Application in Europe of a urine-based rapid diagnostic test for confirmation of Schistosoma mansoni infection in migrants from endemic areas

2015 ◽  
Vol 20 (23) ◽  
Author(s):  
S L Becker ◽  
H Marti ◽  
S Zimmermann ◽  
D Vidacek ◽  
M Herrmann ◽  
...  
Keyword(s):  
Abdominal Pain ◽  
Schistosoma Mansoni ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Rectal Bleeding ◽  
Clinical Management ◽  
Point Of Care ◽  
Rectal Biopsy ◽  
Non Invasive ◽  
Persistent Abdominal Pain

In February 2015, a male patient from Eritrea with persistent abdominal pain and rectal bleeding was diagnosed with Schistosoma mansoni infection upon examination of a rectal biopsy. In May 2015, repeated stool microscopy identified S. mansoni infection in another Eritrean patient with abdominal pain and considerable eosinophilia (34%). Use of point-of-care circulating cathodic antigen (POC-CCA) tests on urine confirmed S. mansoni infection in both patients. Wider application of non-invasive POC-CCA urine tests will improve schistosomiasis diagnosis and clinical management in migrants.

scholarly journals Evaluation of an Antigen Detection Rapid Diagnostic Test for Detection of SARS-CoV-2 in Clinical Samples

COVID ◽  
2021 ◽  
Vol 1 (4) ◽  
pp. 775-783
Author(s):  
Hoi-Ying Lam ◽  
Ka-Yi Leung ◽  
Ruiqi Zhang ◽  
Danlei Liu ◽  
Yujing Fan ◽  
...  
Keyword(s):  
Viral Load ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Large Scale ◽  
Cross Reactivity ◽  
Antigen Detection ◽  
Youden Index ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Large Scale Screening

Antigen detection rapid diagnostic tests have been developed for first-line large-scale screening given their rapidity, simplicity, and accuracy. This study evaluates the diagnostic performance of an antigen detection rapid diagnostic test (BLOK BioScience, London, UK) detecting SARS-CoV-2 nucleocapsid protein. Serially diluted SARS-CoV-2 isolate and 110 NPS from COVID-19 patients were tested to determine the test’s sensitivity, and other viral isolates and 20 NPS from non-infected individuals were, for specificity, also tested. Ten clinical samples from COVID-19 patients with SARS-CoV-2 variants, including alpha, beta, gamma, delta, and eta variants, were collected to evaluate the test’s potential application in detecting emerging variants. Overall sensitivity was 92%, and stratifying into viral loads yielded 100% for Ct < 25 samples including SARS-CoV-2 variants, but 11.11% for Ct ≥ 30 samples. The analytical sensitivity of log10 TCID50/mL 2.0 was identified for SARS-CoV-2. Ninety-seven percent specificity with only SARS-CoV cross-reactivity lead to the Youden index of 0.89. The rapid diagnostic test has a high sensitivity for detecting SARS-CoV-2 in high viral load samples, possibly including emerging SARS-CoV-2 variants, but reduced sensitivity in low viral load samples suggests its optimized usage as a complementary testing method to other tests, including RT-PCR or a point-of-care test for large-scale screening, particularly for pandemic areas or airport border infection control.

The utility of point-of-care urine trypsinogen dipstick test for diagnosing acute pancreatitis in an emergency unit

2021 ◽  
Author(s):  
Amar Simha ◽  
Atul Saroch ◽  
Ashok K Pannu ◽  
Deba P Dhibar ◽  
Navneet Sharma ◽  
...  
Keyword(s):  
Acute Pancreatitis ◽  
Abdominal Pain ◽  
Diagnostic Accuracy ◽  
Diagnostic Test ◽  
Sensitivity And Specificity ◽  
Pain Sensitivity ◽  
Point Of Care ◽  
Emergency Unit ◽  
Dipstick Test ◽  
Low Sensitivity

Background: A point-of-care diagnostic test for acute pancreatitis could help in early triage and management of this condition. Materials & methods: Urine trypsinogen dipstick test (UTDT) was performed in consecutive cases suspected to have acute pancreatitis and diagnostic accuracy calculated. Results: Of 187 patients, 90 were have acute pancreatitis and UTDT was positive in 61 (67.7%). In the 97 non pancreatitis cases, UTDT was positive in nine (9.3%). The sensitivity and specificity of UTDT for acute pancreatitis was 67.8% and 90.7%, respectively. In patients presenting within 3 days of abdominal pain, sensitivity and specificity were 72.7% and 91.8%, respectively. Discussion: While offering the possibility of a point of care diagnosis, the low sensitivity of UTDT could be a concern with its routine use.

scholarly journals Sensitive Molecular Diagnostics for Cutaneous Leishmaniasis

2017 ◽  
Vol 4 (2) ◽  
Author(s):  
Orli Sagi ◽  
Anat Berkowitz ◽  
Shlomi Codish ◽  
Victor Novack ◽  
Aviv Rashti ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Leishmania Major ◽  
Point Of Care ◽  
Leishmania Species ◽  
Rapid Diagnosis ◽  
Clinical Samples ◽  
Leishmania Braziliensis ◽  
Multiplex Qpcr ◽  
Highly Sensitive ◽  
Pcr Multiplex

Abstract Background Rapid diagnosis of cutaneous leishmaniasis (CL) and identification of Leishmania species is highly important for the disease management. In Israel, CL is caused mainly by Leishmania major and Leishmania tropica species. Methods We established an easy to handle point of care lesion-swabbing, combined with a highly sensitive multiplex real time PCR (multiplex qPCR) for accurate and rapid diagnosis of Leishmania species. Results Using three probes: one general for: Leishmania species, and two specific for L major, and L tropica, we screened 1783 clinical samples collected during two years. Leishmania species was found in 1086 individuals, 1008 L major, and 70 L tropica. Eight samples positive for Leishmania species only, were further tested using a second set of multiplex qPCR developed, and were found positive for Leishmania braziliensis and Leishmania infantum/donovani (2 and 6 samples, concomitantly). Conclusions Taken together, the test enabled diagnostics and better treatment of Leishmania infections from the Old World (1078 samples) and the New World (8 samples), and the subtyping of the dominant strains in the region, as well as in returning travelers’.

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