BENGALURU: Researchers at the Indian Institute of Science (IISc) have developed an alternative method of Covid testing that can be used in areas that are resource-starved. Currently, real-time reverse transcription–polymerase chain reaction (real-time, or quantitative, RT-PCR) test is one of the fastest and most accurate ways to detect the Covid-19 virus, making it the most widely used across the world. However, the test has several limitations, most common among which is its use of real-time monitoring and the need for a thermal cycler.
RT-PCR testing requires certain reactions to take place at different temperatures, which is why a thermal cycler is used. The cycler helps in regulating and maintaining certain temperatures, according to the reactions that need to take place. Meanwhile, real-time monitoring helps in detecting the severity of the infection, as well as helps in delivering results faster than other conventional tests. However, both the
features of the quantitative RT-PCR tests mean that very specific conditions and equipments need to be present for accurate testing.
IISc researchers Priyanka Valloly and Rahul Roy, of the Department of Chemical Engineering, have found a way to eliminate the need for both these prerequisites in Covid testing. The researchers developed a new method of testing, called quantitative endpoint RPA (qeRPA). They make use of Recombinase Polymerase Amplification (RPA), an alternative method of testing, where reactions are monitored at room temperature. This removes the need for a thermal cycler.
Meanwhile, the researchers developed a model for RPA testing that provides consistent results with those done through real-time RT-PCR, without needing to make use of real-time monitoring. When tested, the researchers found that both -- testing using qeRPA and quantitative RT-PCR -- had consistent results. However, the use of qeRPA removed the need for a thermal cycler as well as real-time monitoring, while ensuring that testing could be done just as accurately.
“The results from qeRPA were consistent with the results obtained from quantitative RT-PCR, while being faster and easier to implement. Therefore, the team hopes that this method could be used to detect nucleic acids like DNA or RNA at diagnostic centres in resource-limited areas such as remote villages and in developing countries, making diagnostics more accessible,” IISc said.