A Novel Rapid, Mobile, Lab-Independent and Sensitive SARS-CoV-2 Test at the Point of Need, to Break the Chain of Infection
COVID-19 testing often relied on people attending testing facilities when they experienced symptoms. The virus therefore often went undetected in asymptomatic people who were nevertheless able to infect others. This consortium developed an accurate, inexpensive diagnostic test for COVID-19 that can be implemented by people within their own homes, before they are symptomatic.
The Need to Diagnose Asymptomatic COVID-19 Cases
Whilst diagnostic testing available at the outset of the COVID-19 pandemic provided a high degree of testing accuracy, people were required to attend a centralised testing facility when they experienced symptoms. Because the SARS-CoV-2 virus can be transmitted by infected individuals before the onset of COVID-19 symptoms or by those who remain asymptomatic, such a diagnostic system is on its own not capable of preventing the spread of the virus at a societal level.
Developing a New Rapid Antigen Test to Curb the Societal Spread of COVID-19
The aim of this consortium was to develop an accurate, inexpensive diagnostic test that can be implemented by people within their own homes before they are symptomatic. It was recognised that such a development had the potential to significantly contribute to disease containment.
The rapid antigen test system developed by this consortium uses lateral flow assays similar to those that are used in pregnancy test kits. To detect the presence of viral proteins in a human sample, the researchers incorporated SARS-CoV-2 antibodies into a paper-based matrix. The binding of viral proteins from a sample to the antibodies can be quantitatively measured by a new electrochemical readout system that translates the amount of binding that takes place into a signal that can be easily interpreted by the user. One of the main advantages of this new electrochemical readout system is the detection of very low amounts of viral proteins. This enables the diagnosis of asymptomatic patients carrying the virus or those at the onset of infection Moreover, this testing mechanism can be used to provide a rapid result in the home, without any specialised or expensive equipment.
The Potential to Enhance Access to Inexpensive Diagnostic Tools
Using a production line established in the team’s laboratory, 240 of the developed rapid antigen tests were assembled and delivered, together with three of the electrochemical read-out devices to the University Hospital Basel. Here, the technology was evaluated against the polymerase chain reaction (PCR) gold standard using clinical samples in real-world conditions. The rapid test demonstrated excellent performance, achieving a sensitivity (its ability to correctly identify the presence of the virus correctly) of 92.1% and a specificity (its ability to identify the absence of the virus correctly) of 96.8%.
The advancements made in this project have the potential to enhance access to accurate and inexpensive diagnostic tools, reduce testing demand on public healthcare systems and curb the societal spread of pandemic diseases such as COVID-19.
Banner image above: The consortium worked to create a rapid, point-of-need diagnostic test. A sample droplet is loaded onto the sample pad (lower left corner) of the assay. The viral proteins in the sample are then immobilised and labelled. The readout device then accurately quantifies the labelled proteins and displays the result on the screen.
