COVID-19 pandemic | ICMR approves dry swab-direct RT-PCR method to scale up testing; here's how it works

Following the evaluation of dry swab-direct RT-PCR testing method and considering its lesser cost and quick turn-around time, the ICMR has now issued an advisory for the use of CSIR-CCMB dry swab method.

What is dry swab-direct RT-PCR testing method?

Dry swab-direct RT-PCR method involves collecting and transporting the nasal swab in dry state. This makes the transportation and handling of the samples easy and less prone to spillage and spread of infection.

In the new method, the step of RNA isolation from the sample has been omitted, and it involves only simple processing of the sample followed by direct RT-PCR using the kit recommended by the ICMR.

By omitting the RNA isolation, the time, cost, and need for extra trained manpower has been decreased. With these features, COVID-19 testing can be easily scaled up at least 2-3 times immediately.

"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," DG-CSIR Dr Shekhar C Mande said.

"RNA extraction, even with automation, takes 4 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 percent," said CCMB Director Dr Rakesh Mishra.

CSIR-CCMB's new method has also been independently corroborated by multiple premier institutes and hospitals such as Centre for DNA Fingerprinting and Diagnostics (CDFD), IISER-Berhapmur, CSIR-NEERI, GMCH-Nagpur, Genepath based in Pune, IGGMSH and MAFSU, Nagpur, and also Apollo Hospitals, Hyderabad.