April 17, 2020 | The diagnostics community continues to aggressively research and innovate for SARS-CoV-2 solutions. The latest this week includes research on saliva-based detection, CRISPR diagnostics, serological testing, and much more.
Literature Updates
Mammoth Biosciences has published results in Nature Biotechnology demonstrating the power of its CRISPR-based diagnostic assay, DETECTR, to detect SARS-CoV-2 from respiratory swab RNA extracts in under 45 minutes. The company says the DETECTR assay offers a faster, lower-cost and visual alternative to traditional qRT-PCR assays and can deliver results in under 45 minutes as visualized on a lateral flow strip, similar to an at-home pregnancy test. DETECTR does not require a complex laboratory setting; it can be performed with portable heat blocks and readily available, “off-the-shelf” reagents and disposable lateral flow strips. The assay offers similar levels of sensitivity and specificity to qRT-PCR tests, with 95% positive predictive agreement and 100% negative predictive agreement. The study was led by infectious disease expert Dr. Charles Chiu, researchers from the Department of Laboratory Medicine at the University of California, San Francisco (UCSF), along with Mammoth’s Chief Technology Officer Dr. Janice Chen and Research Lead Dr. James Broughton, and the California Department of Public Health. The researchers validated the method using contrived reference samples and clinical samples from US patients, including 36 patients with COVID-19 infection and 42 patients with other viral respiratory infections. DOI: 10.1038/s41587-020-0513-4
Patients with COVID-19 commonly have neurologic manifestations, based on findings of a study involving 214 hospitalized patients in Wuhan, China. Results, published in JAMA Neurology, suggest clinicians should suspect severe acute respiratory syndrome coronavirus 2 infection as a differential diagnosis to avoid delayed diagnosis or misdiagnosis and lose the chance to treat and prevent further transmission. DOI: 10.1001/jamaneurol.2020.1127
Mayo Clinic cardiologists and radiologists propose algorithms, based on expert consensus, to guide the triage of COVID-19 patients with ST-segment elevation and acute myocardial injury. This is to reduce the number of patients undergoing procedures that present unnecessary risks due to a “false signal” of coronary artery disease. Recommended use of echocardiogram or coronary CT angiogram for patients with suspected or confirmed COVID-19 is also covered in an article being published in Mayo Clinic Proceedings. DOI: 10.1016/j.mayocp.2020.04.005
Researchers at UC San Diego Health have produced the first empirical evidence strongly associating loss of smell and taste with COVID-19 infections. Their study findings, published in the International Forum of Allergy & Rhinology, suggest clinicians should include sensory impairment as a standard screening measure. The loss of smell and taste was typically profound but, encouragingly, with a high recovery rate usually within two to four weeks of infection. Sensory return typically matched the timing of disease recovery. Interestingly, researchers found that patients reporting a sore throat more often tested negative for COVID-19. DOI: 10.1002/alr.22579
Meanwhile, in a review published in Laryngoscope Investigative Otolaryngology, a University of Cincinnati ear, nose and throat specialist concludes that loss of smell could be an early indicator of a COVID-19 infection. COVID-19 is not associated with symptoms typical of a viral cold, such as nasal blockage or mucus production, and the distinction is what makes it easy to distinguish the novel coronavirus from seasonal allergies. When loss of smell occurs as an initial symptom it is particularly instructive. Press release
Swiss researchers have developed a new COVID-19 test that quickly and accurately detects viral RNA, and could be a practical alternative to PCR tests, as reported in ACS Nano. The potentially more accurate diagnostic is based on plasmonic photothermal sensing. It utilizes a technique that detects interactions between molecules on the surface of a metallic nanostructure. The team made DNA probes that recognized specific SARS-CoV-2 RNA sequences and attached them to gold nanoparticles. When they added pieces of the virus's genome, the RNA attached to the complementary probes like a zipper being closed. Heating up the nanoparticles made it more difficult for imperfectly matched sequences to remain attached, reducing false-positives and making it possible to discriminate between SARS-CoV-2 and its close relative, SARS-CoV-1. The assay detected amounts of viral RNA below those present in respiratory swabs in a matter of minutes, but still needs to be tested on intact viral RNA from patient samples. DOI: 10.1021/acsnano.0c02439
Industry News
Beaumont Health’s Research Institute is launching what it calls “America’s largest serological testing study” for COVID-19 antibodies. The Michigan health system will begin by identifying the number of people across its 38,000 employees and thousands of affiliates who have COVID-19 antibodies who never reported any symptoms. Participation is voluntary. To detect and analyze COVID-19 antibody levels, Beaumont Health will use two PerkinElmer EUROLabWorkstations and EUROIMMUN Anti-SARS-CoV-2 ELISA testing kits which recently received CE marking in Europe. After initial results are obtained from Beaumont patients and staff, the testing capability will be made available to other area hospital systems as needed. Beaumont intends to use data collected through this study as part of its own return to work process. Press release.
ERA-EDTA, one of the world’s largest nephrology associations, has created a European database collecting data on individual dialysis and transplant patients with COVID-19 to measure outcomes and define risk factors. The rationale is conflicting reports suggesting patients on dialysis or with a kidney transplant have limited symptomatology. The experiences of Spanish patients on dialysis, who are particularly frail and old, also may not represent the dialysis population of other countries where organ transplantation rates are lower. Nephrologists across Europe are being invited to submit their patients’ data. Press release.
Personnel at Ohio State Wexner Medical Center have been working overtime to address a critical shortage of COVID-19 test kit components. Working with faculty and staff in the university's colleges of Engineering and Dentistry, they have created and 3D-printed more than 50,000 new swabs used to collect samples that will be shared with hospitals across the state. The U.S. Food and Drug Administration (FDA) also just approved an in-house recipe for viral transport media (VTM), the sterile solution needed to transport the swabs, which was developed by a rapidly assembled team of Ohio State researchers. Enough VTM has been produced for up to 30,000 test kits, and the recipe is being shared with other health systems to help make testing more widely available. Last month, Ohio State Wexner Medical Center jointly developed a rapid, sensitive diagnostic test for COVID-9 with Battelle to help “flatten the curve.” Production of portable shields using 3D printers and an injection molding machine, reducing the need for PPE during intubation procedures, is another of the nearly 80 research projects underway related to COVID-19. Press release.
A large, state-funded COVID-19 Testing Initiative launched by the University of Maryland School of Medicine (UMSOM) will be running as many as 20,000 tests per day within the next few months, significantly improving access to testing in Maryland. Patient samples will be processed on robotic platforms previously used for research studies to characterize the bacteria that compose the human microbiome. An on-campus testing facility federally certified to perform laboratory developed tests will analyze the samples. Turnaround time on results will be within 24 to 48 hours, versus waits of a week or more currently. The UMSOM Department of Pathology plans to seek emergency use authorization from the FDA for COVID-19 testing and submit data to the agency to verify the test's performance in detecting both true positive and true negative results. Press release.
A new saliva test for coronavirus developed by Rutgers RUCDR Infinite Biologics in partnership with Spectrum Solutions and Accurate Diagnostic Labs was granted emergency use authorization by the FDA. The tests are available to the RWJBarnabas Health network, which has partnered with Rutgers University and is New Jersey's most comprehensive health care system. Rutgers, in partnership with the Middlesex County government and RWJBarnabas Health, is making the test available to county residents at a drive thru testing facility. Self-collection of saliva is quicker and more scalable than nasopharyngeal or oropharyngeal swab collection, meaning significantly more people can be tested and healthcare professionals are at lower risk of infection and more personal protective equipment is preserved for patient care. Researchers are knowledge sharing with some of the world's largest life sciences companies involved in COVID-19 testing. RUCDR also just launched a genetic testing service for the coronavirus that can test thousands of samples daily—a number that may increase to tens of thousands with the new saliva test. Press release.