Loop-Mediated Isothermal Amplification-Assay Rapidly Diagnoses COVID-19
|
By LabMedica International staff writers Posted on 25 Aug 2020 |
|
Image: The Genie III instrument was used for the reverse transcriptase loop-mediated isothermal amplification-assay called N1 gene Single Tube Optigene LAMP (N1-STOP-LAMP) for COVID-19 (Photo courtesy of OptiGene Ltd).
The SARS-CoV-2 (COVID-19) pandemic of 2020 has resulted in unparalleled requirements for RNA extraction kits and enzymes required for virus detection, leading to global shortages. This has necessitated the exploration of alternative diagnostic options to alleviate supply chain issues.
The loop-mediated isothermal amplification (LAMP) assay is robust, rapid and straightforward, yet retains high sensitivity. These features have seen the LAMP assay and the inclusion of a reverse transcriptase (RT-LAMP) implemented for a broad range of molecular diagnostic applications extending from infectious diseases, virus, bacteria and parasites, to cancer.
Microbiologists at the University of Melbourne (Melbourne, Australia) and their associates collected 157 confirmed-positive nasopharyngeal swabs between the March 23 and April 4 2020. The team developed a rapid molecular test called N1 gene Single Tube Optigene LAMP (N1-STOP-LAMP), a reverse transcriptase loop-mediated isothermal amplification-assay. Copan flocked swabs were collected and directly inoculated on site in either 1 mL or 3 mL of universal transport medium (UTM, Copan Diagnostics, Murrieta, CA, USA).
A 200 µL aliquot of Copan UTM was processed through the QIAsymphony DSP Virus/Pathogen Mini Kit (Qiagen, Hilden, Germany) on the QIAsymphony SP instrument. Each N1-STOP-LAMP reactions were assembled in either 8-tube Genie strips (OptiGene Ltd, Horsham, UK) or 96-MicroAmp-Fast-Optical reaction plate (Applied Biosystems, Foster City, CA, USA). Strip tubes were loaded onto the OptiGene Genie-II or Genie-III and 96-well plates run on an Applied Biosystems’ QuantStudio 7 thermocycler.
The scientists reported that the assay evaluation by assessment of 157 clinical specimens previously screened by E-gene RT-qPCR revealed the N1-STOP-LAMP assay had sensitivity and specificity of 87% and 100%, respectively. Results were fast, with an average time-to-positive (Tp) for 93 clinical samples of 14 ± 7 minutes. The team also evaluated assay performance against FDA guidelines for implementation of emergency-use diagnostics and established a limit-of-detection of 54 Tissue Culture Infectious Dose 50 per mL (TCID50 mL−1), with satisfactory assay sensitivity and specificity. A comparison of 20 clinical specimens between four laboratories showed excellent inter-laboratory concordance; performing equally well on three different, commonly used thermocyclers, pointing to the robustness of the assay.
The authors concluded that with a simplified workflow, The N1 gene Single Tube Optigene LAMP assay is a powerful, scalable option for specific and rapid detection of SARS-CoV-2 and an additional resource in the diagnostic armamentarium against COVID-19. The study was published on August 5, 2020 in the Journal of Medical Microbiology.
Related Links:
University of Melbourne
Copan Diagnostics
Qiagen
OptiGene Ltd
Applied Biosystems
The loop-mediated isothermal amplification (LAMP) assay is robust, rapid and straightforward, yet retains high sensitivity. These features have seen the LAMP assay and the inclusion of a reverse transcriptase (RT-LAMP) implemented for a broad range of molecular diagnostic applications extending from infectious diseases, virus, bacteria and parasites, to cancer.
Microbiologists at the University of Melbourne (Melbourne, Australia) and their associates collected 157 confirmed-positive nasopharyngeal swabs between the March 23 and April 4 2020. The team developed a rapid molecular test called N1 gene Single Tube Optigene LAMP (N1-STOP-LAMP), a reverse transcriptase loop-mediated isothermal amplification-assay. Copan flocked swabs were collected and directly inoculated on site in either 1 mL or 3 mL of universal transport medium (UTM, Copan Diagnostics, Murrieta, CA, USA).
A 200 µL aliquot of Copan UTM was processed through the QIAsymphony DSP Virus/Pathogen Mini Kit (Qiagen, Hilden, Germany) on the QIAsymphony SP instrument. Each N1-STOP-LAMP reactions were assembled in either 8-tube Genie strips (OptiGene Ltd, Horsham, UK) or 96-MicroAmp-Fast-Optical reaction plate (Applied Biosystems, Foster City, CA, USA). Strip tubes were loaded onto the OptiGene Genie-II or Genie-III and 96-well plates run on an Applied Biosystems’ QuantStudio 7 thermocycler.
The scientists reported that the assay evaluation by assessment of 157 clinical specimens previously screened by E-gene RT-qPCR revealed the N1-STOP-LAMP assay had sensitivity and specificity of 87% and 100%, respectively. Results were fast, with an average time-to-positive (Tp) for 93 clinical samples of 14 ± 7 minutes. The team also evaluated assay performance against FDA guidelines for implementation of emergency-use diagnostics and established a limit-of-detection of 54 Tissue Culture Infectious Dose 50 per mL (TCID50 mL−1), with satisfactory assay sensitivity and specificity. A comparison of 20 clinical specimens between four laboratories showed excellent inter-laboratory concordance; performing equally well on three different, commonly used thermocyclers, pointing to the robustness of the assay.
The authors concluded that with a simplified workflow, The N1 gene Single Tube Optigene LAMP assay is a powerful, scalable option for specific and rapid detection of SARS-CoV-2 and an additional resource in the diagnostic armamentarium against COVID-19. The study was published on August 5, 2020 in the Journal of Medical Microbiology.
Related Links:
University of Melbourne
Copan Diagnostics
Qiagen
OptiGene Ltd
Applied Biosystems
Platinum Member
Automated Coagulation Analyzer
Hemolumi H6
Gold Member
Quantitative POC Immunoassay Analyzer
EASY READER+
New
MR-proADM Test
B•R•A•H•M•S MR-proADM KRYPTOR test
New
Slide Scanner System
NanoZoomer S540MD
Latest Molecular Diagnostics News
- New RNA Detection Tool Shows Promise for HIV and Other Viral Testing
- Tissue-Specific Vesicle Isolation Expands Molecular Insights Into Liver Disease
- Whole Genome Sequencing Solution Targets Unsolved Rare Disease Cases
- Validated Test Predicts Recurrence Risk and Radiation Benefit in Early-Stage Breast Cancer
- Study Shows How Genome Reference Bias Can Mislead Preventive Testing
- Genomic Screening Expands Detection of Treatable Conditions in Newborns
- Age-Based Genetic Testing May Miss Most Inherited Cancer Risk Variants
- Pooled Sputum Testing Offers Lower-Cost Molecular Diagnosis for Tuberculosis
- Expanded Sequencing Panel Supports Myeloid Malignancy Variant Profiling
- Tumor Markers Help Predict Response to Less Intensive HER2+ Chemotherapy
- New NGS Suite Expands Clonality and MRD Research in Lymphoid Malignancies
- Tumor-Informed ctDNA Test Shows Utility Across Gastrointestinal and Gynecologic Cancers
- New Molecular Testing Support to Strengthen Ebola Surveillance in DRC
- Functional Testing From Skin Biopsy Improves Detection of Mitochondrial Disease
- Blood Test Detects Molecular Signals of Early Liver Cancer Progression
- Breast Milk DNA Test Investigated for Early Breast Cancer Detection
Channels
Clinical Chemistry
view channel
Blood Protein May Help Identify Treatment-Resistant Psychosis
Psychotic disorders, including schizophrenia, are diagnosed primarily through assessment of symptoms and behaviors such as hallucinations, delusions, and disordered thinking. Treatment-resistant psychosis... Read more
Electrochemical Biosensor Rapidly Detects Cerebrospinal Fluid Leaks
Cerebrospinal fluid surrounds the brain and spinal cord and helps protect them from physical impact. After severe head trauma or brain surgery, it can leak through skull defects and drain from the nose or ears.... Read more
Molecular Diagnostics
view channel
New RNA Detection Tool Shows Promise for HIV and Other Viral Testing
RNA viruses such as human immunodeficiency virus (HIV) require assays that can detect very low levels of viral genetic material. Clinical and environmental testing can also expose enzymes to harsh assay... Read more
Tissue-Specific Vesicle Isolation Expands Molecular Insights Into Liver Disease
Liver disease can produce overlapping molecular signals from cirrhosis and hepatocellular carcinoma, complicating blood-based analysis. Liquid biopsy approaches that examine extracellular vesicles face... Read more
Hematology
view channel
New Donor Genetic Marker May Help Predict Stem Cell Transplant Success
Donor selection for hematopoietic stem cell transplantation plays a major role in relapse risk and survival for patients with blood cancers and other blood disorders. Despite advances in genotyping, uncertainty... Read more
Updated Ferritin Thresholds Improve Detection of Iron Deficiency
Iron deficiency is one of the most common health conditions worldwide, yet its nonspecific symptoms can delay diagnosis for months. Variation in testing practices and ferritin thresholds may contribute... Read more
Immunology
view channel
FDA Approval Adds Automated Testing Option for Parvovirus B19 Serology
Human Parvovirus B19 is a highly contagious erythrovirus transmitted mainly through respiratory droplets and close contact. Diagnosis relies on IgM antibodies to detect active infection and IgG antibodies... Read more
Blood-Based Immune Aging Map Could Help Spot Disease Risk Earlier
Chronological age does not always reflect immune health or future disease risk. Two adults of the same age can have immune systems that age very differently, with some remaining resilient while others... Read more
Pathology
view channel
Molecular Testing Refines Barrett’s Esophagus Progression Risk Beyond Biopsy Findings
Barrett’s esophagus is a precancerous condition associated with increased risk of esophageal adenocarcinoma. Routine endoscopic biopsy findings guide surveillance and therapy, but histopathology may not... Read more
AI Histopathology Tool Distinguishes Ewing Sarcoma for Diagnosis
Ewing sarcoma is a rare malignant tumor that mainly affects children, adolescents, and young adults. It usually arises in bone but can also develop in soft tissue, where its microscopic appearance may... Read more
Rapid Mass Spectrometry Test May Aid Glioma Margin Decisions
Glioma brain tumors are highly infiltrative and can extend into nearby healthy brain tissue, making tumor margins difficult to define during surgery. Residual tumor cells may contribute to recurrence and... Read more
Genomic Classifier Predicts Benefit From Adding Hormone Therapy to Salvage Prostate Radiation
Men who have undergone prostatectomy for prostate cancer may later develop a detectable or rising prostate-specific antigen, prompting salvage radiation therapy. A key challenge is determining who is most... Read moreTechnology
view channel
Laser-Based Swab Analysis Shows Promise for Detecting Disease-Linked Odor Patterns
Disease-related changes in volatile organic compounds can alter body odor, producing measurable patterns in exhaled breath and bodily fluids. Current analytical methods can be complex, time-consuming,... Read more
Laser-Enhanced Assay Boosts Sensitivity for Colorectal Cancer Biomarker Detection
Colorectal cancer is the third most commonly diagnosed cancer and the second leading cause of cancer-related death worldwide. Early detection remains critical, but cancer biomarkers can produce only faint... Read more
Industry
view channel
Global TB Summit Connects Diagnostic Testing With Prevention and Clinical Care
Tuberculosis remains a major global infectious disease challenge despite declining deaths. In 2024, an estimated 10.7 million people worldwide developed the disease and nearly 1.2 million died from it.... Read more
