The Indian Council for Medical Research (ICMR) has approved a simple and fast method for COVID-19 testing which can not only increase the number of RT-PCR tests but can also bring down costs, the Council for Scientific and Industrial Research (CSIR) said on Saturday. The method — Dry Swab-Direct RT-PCR — developed by CSIR's Centre for Cellular and Molecular Biology, Hyderabad, is a variation of the existing gold standard RT-PCR method and can easily scale up the testing by 2 to 3 fold with no new investment of resources.
"After evaluating this method and finding an overall concordance of 96.9 per cent, ICMR has now issued an advisory for the use of CSIR-CCMB dry swab method, considering its lesser cost and quick turn-around time," the CSIR said. The CCMB has been testing samples for coronavirus since April. Having worked closely with healthcare workers of Telangana, it identified some of the key issues that slow the testing process. In response to it, the researchers developed the Dry Swab RNA-extraction free testing method for COVID-19.
The Dry Swab-Direct RT-PCR method involves collecting and transporting the nasal swab in dry state, as opposed to using the viral transport medium VTM, which makes the transportation and handling of the samples easy and less prone to spillage and spread of infection. Secondly, the step of RNA isolation from the sample is omitted and involves only simple processing of the sample followed by direct RT-PCR using the kit recommended by the ICMR. "Omitting the step of RNA isolation offers a huge benefit over the conventional method, as the RNA isolation is a major bottleneck in terms of time, cost and trained manpower. Given this, with the same resources and no additional cost, more samples can be tested and can be easily scaled up at least 2-3 times immediately," the CSIR said.
Rakesh Mishra, director, CCMB said RNA extraction, even with automation, takes four hours for roughly 500 samples. "VTM and RNA extraction both add a significant burden on money and time required for mass testing for coronavirus. We believe the technique's merit holds for all kinds of settings and has the potential of bringing the costs and time of testing by 40-50 per cent," the CSIR said. CSIR director general Shekhar Mande said the Dry-Swab Direct RT-PCR method is cost effective, easy to implement with no requirement of new kits and existing manpower can perform this with no additional training and hence could make a significant contribution to ramping up the testing capacity in the country quickly.