The Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology (CSIR-CCMB) recently received permission from the Indian Council of Medical Research (ICMR) for commercial utilization of the dry swab RNA-extraction free testing method to detect Covid-19.
Key Points about Dry Swab Method
The dry swab method has a 96.9% consistency level. The current comparison between the conventional swab-VTM-RNA extraction-RT-PCR method and the simplified dry swab-RT-qPCR protocol suggests that with the direct elution of dry swabs into a simple buffered solution, the molecular detection of SARS-CoV-2 via endpoint RT-PCR doesn’t significantly compromise the sensitivity.
Conventional Testing Method
The conventional testing method involves nasopharyngeal or oropharyngeal swab samples collected from suspected coronavirus patients by collection centres. These samples are then transported, sometimes over considerable distances, to testing centres. The swab samples are typically placed in a Viral Transport Medium (VTM) and sealed to prevent leakage, which adds to processing times at both sample collection and testing centres. Notably, the RNA extraction process can take roughly four hours for approximately 500 samples. Both VTM and RNA extraction processes pose a significant burden on funding and time needed for large-scale testing.
New and Simplified Testing Method
The dry swab technique, a more streamlined method, eliminates the need for VTM and the RNA extraction process. This alternative can be used directly for RT-PCR testing, potentially reducing costs and testing time by 40-50%. It also promises safer testing processes and significantly increased screening capacity with immediate effect. Furthermore, the implementation requires no novel kits and existing personnel can perform this task without additional training.
Benefits of Dry Swab Method
The new dry swab method promises to scale up testing capabilities and is more cost-effective than conventional RT-PCR tests. It also provides quicker results, reducing waiting time for patients.
RT-PCR Test Overview
The RT-PCR technique was created by American biochemist Kary Mullis, who won the Nobel Prize for Chemistry in 1993 for his innovation. This test process involves creating copies of a segment of DNA using an enzyme called Polymerase. This chain reaction demonstrates how DNA fragments are exponentially copied – one copy becomes two, then four, and so forth. To ascertain the presence of the virus, a fluorescent DNA binding dye known as the “probe” is added to the DNA and detected on a fluorometer. As Covid-19 is composed of RNA, this substance is converted into DNA using a technique known as reverse transcription. The converted DNA is then copied and amplified.
Source: TH