April 24, 2020 | As SARS-CoV-2 (COVID-19) continues impacting individuals and communities on a global scale, the diagnostics community is working around the clock to provide both relief and solutions. Their latest efforts include 3D-printed swabs, biosensors that detect COVID-19 in less than one minute, and much more.
Literature Updates
In an article published in the American Journal of Roentgenology, researchers from six U.S. institutions caution against using chest CT for coronavirus diagnosis and instead reserving it for evaluation of complications of COVID-19 pneumonia or for assessment if alternative diagnoses are suspected. The rationale is that misdiagnosing even a single patient could result in large outbreaks among future contacts; features most characteristic of COVID-19 pneumonia are also present with other conditions, both infectious and noninfectious; and wide deployment of CT is hazardous in terms of use of personal protective equipment already limited in availability, clustering of affected and nonaffected patients in the radiology department and increasing the risk of disease transmission among imaging staff. DOI: 10.2214/AJR.20.23202
Engineers at Washington University in St. Louis is developing a rapid COVID-19 test using a new biolabeling technology called plasmonic-fluor composed of gold nanoparticles coated with conventional dyes. The highly sensitive and accurate biosensor is based on an ultrabright fluorescent nanoprobe, which has the potential to be broadly deployed—and will be especially useful in resource-limited conditions because it requires fewer complex instruments to read the results. Researchers hypothesize that the biosensor, which works by increasing the fluorescence signal to background noise, will be 100 times more sensitive than the conventional SARS-CoV-2 antibody detection method. In a study published in Nature Biomedical Engineering, they showed plasmonic-fluor was able to achieve up to a 6,700-fold brighter fluorescent nanolabel compared with conventional dyes. Using this nanolabel as an ultrabright flashlight, they demonstrated the detection of extremely small amounts of target biomolecules in biofluids and even molecules present on the cells. The technology has been licensed to Auragent Bioscience LLC , which is further developing and scaling up the production of plasmonic-fluors for commercialization. DOI: 10.1038/s41551-020-0547-4
Meanwhile, researchers in Korea report in ACS Nano that they have developed a biosensor that detects SARS-CoV-2 in nasopharyngeal swabs from patients with COVID-19 in less than one minute. The test is based on a field-effect transistor—a sheet of graphene with high electronic conductivity. Antibodies against the SARS-CoV-2 spike protein were attached to the graphene and, when either purified spike protein or cultured SARS-CoV-2 virus was added to the sensor, binding to the antibody caused a change in the electrical current. When the technique was tested on nasopharyngeal swabs collected from patients with COVID-19 or healthy controls, the sensor could discriminate between samples from sick and healthy patients without any sample preparation. The new test was two to four times less sensitive than real-time reverse transcription-polymerase chain reaction (the technique used by most COVID-19 diagnostic tests), but different materials could be explored to improve the signal-to-noise ratio, the researchers say. DOI: 10.1021/acsnano.0c02823
Study findings published in Lancet, indicating the rate of infection among NHS staff treating patients in the UK is no higher than for those in non-clinical roles, demonstrate how delivering staff testing during a pandemic is feasible. This suggests transmission of SARS-CoV-2 from patients to NHS staff may reflect wider patterns of SARS-CoV-2 transmission in the community, consistent with observations in China where staff testing was widespread. Researchers at Newcastle Hospitals and University further report that growth in cases clearly flattened after the introduction of social distancing measures. An efficient, robust system of testing has enabled 1,414 health care workers to return more rapidly to NHS service in Newcastle in recent weeks, the vast majority directly into patient care. Test results are returned to staff within 48 hours of initial contact. DOI: 10.1016/S0140-6736(20)30970-3
Other News
Acute and chronic kidney disease is strongly associated with severity of disease and fatal outcomes in COVID-19 patients. Evaluation of a patient's kidney risk status at the time of COVID-19 diagnosis, through recovery and during follow-on monitoring, can be of potentially high clinical value.
Renalytix AI, the AIM-traded developer of clinical grade artificial intelligence in vitro diagnostics for kidney disease, announces that the KidneyIntelX platform will be used by investigators from the Icahn School of Medicine at Mount Sinai to assess the risk of adverse kidney events in patients diagnosed with COVID-19. The KidneyIntelX platform will be used in a large study of COVID-19 admitted patients at Mount Sinai called "Pred-MAKER" (Prediction of Major Adverse Kidney Events and Recovery). Pred-MAKER will study clinical features and biomarkers, including multiple plasma biomarkers and urine proteomics and RNA sequences, as predictors of major adverse kidney events in patients hospitalized with COVID-19. The study has been submitted for Institutional Review Board (IRB) review and approval. Press release.
OpGen and Karolinska Institutet, Sweden, are working to identify bacterial co-infections in patients admitted to the ICU for COVID-19 pneumonia using the Unyvero HPN panel. High-risk COVID-19 patients, especially in intensive care units and on ventilation, many of whom may be elderly or have preexisting conditions that compromise their immune system, are at a higher risk of acquiring bacterial co-infections that pose severe life-threatening complications. These co-infections are not always easily determined based on clinical symptoms alone, and, if they go unnoticed or diagnosis is delayed, it can lead to dire outcomes including mortality. Press release.
University of Louisville’s Additive Manufacturing Institute of Science & Technology, along with faculty and students in the Schools of Dentistry, Engineering and Medicine, have created 3D-printed swabs made of a pliable resin material to help fill the gap in COVID-19 test kits. Collaborators include Envisiontech for the resin and NewPro3D for speeding up printing time. The goal is to print 385 swabs in less than an hour, and then make the manufacturing processes available to companies within Kentucky for large-scale production. Clinical trials of the swabs have just begun and, if results are favorable, they could be ready for widespread use in early May. Press release.
Clinical laboratory physicians and scientists at UC San Diego Health have launched a pair of serological tests that will look for novel coronavirus antibodies signaling previous infection by SARS-CoV-2 even in the absence of tell-tale symptoms. The effort is built on blood tests developed by Diazyme Laboratories, Inc., a division of General Atomics, which test for the presence of two of the body's five classes of antibodies: IgG and IgM. Looking for the two types of antibodies together increases treating physicians’ confidence in being able to differentiate between a recent infection and past exposure. Initial capacity for serological testing will be a combination of up to 1,200 of IgM or IgG antibody tests per day, with results within 24 hours. The first testing cohort will likely be healthcare workers, both to identify those in a convalescent phase after a documented exposure and assess individuals who are suspected of having COVID-19 but have not been tested by PCR-based diagnostics and are recovering at home under quarantine. Only one rapid serological test, which claims results within 15 to 20 minutes, currently has received Emergency Use Authorization from the FDA. The coronavirus blood testing program at UC San Diego Health is, for now, open-ended. Press release.
Israeli researchers from Ben-Gurion University (BGU) of the Negev report using artificial intelligence to develop an algorithm-based test that can speed COVID-19 testing eightfold and help locate asymptomatic carriers. The key to quickly locating and isolating asymptomatic carriers is to divide samples into different pools, they say. The test is currently being conducted by a laboratory robot, and the next stage of the experiment is to test the medical services personnel at Soroka University Medical Center. The new test is just one of more than 50 initiatives underway as part of the BGU COVID-19 Response Effort. News article.
Diagnostic healthcare company Nanosticks will be developing and validating ClarityDX COVID-19, a blood test to predict the severity of COVID-19 disease. Patient samples will be collected by its collaborators, the Canadian BioSample Repository at the University of Alberta and Florida-based Century Clinical Research Institute. The plan is to use the ClarityDX biomarker platform to measure viral load along with other known immunological COVID-19 severity risk factors, with the resulting blood test using machine learning algorithms to determine the risk level in SARS-CoV-2-positive patients. Press release.