Dry swab tech for Covid testing cuts cost, time: CCMB

CCMB says its dry swab technology for Covid-19 testing lowers cost, time by 50%

The institute announced that their method received the ICMR approval for use in settings where automated RNA extraction is not available

Representative image. Credit: iStock.

The Centre for Cellular and Molecular Biology has announced that a dry swab technology it developed lowers the cost and time of Covid-19 testing by about 50 per cent.

After evaluating the 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.

Director General-CSIR, Dr Shekhar C Mande, said that the Dry-Swab Direct RT-PCR method is easy to implement with no new kits requirement and existing manpower can perform the tests with no additional training. Hence this could make a significant contribution to ramping up the testing capacity in the country quickly.

The modified method has been independently corroborated by Centre for DNA Fingerprinting and Diagnostics (CDFD), IISER-Berhapmur, CSIR-NEERI, GMCH-Nagpur, Genepath based in Pune, IGGMSH and MAFSU, Nagpur and Apollo Hospitals, Hyderabad.

The Hyderabad based CSIR institute has been testing samples for the virus since April 2020.

Working closely with the healthcare workers of Telangana, CSIR-CCMB researchers identified certain issues that are prolonging the testing process, time. So, CSIR-CCMB developed a dry swab RNA-extraction free testing method to detect Covid-19 virus.

In the conventional testing method, nasopharyngeal or oropharyngeal swab samples are collected at the sample collection centres and transported to testing centres, sometimes hundreds of kms away.

These swab samples are generally placed in a liquid called Viral Transport Medium (VTM). To avoid leakage, the samples are packed heavily adding to sample processing time at the sample collection and also testing centres. Despite such care, there are leakages from samples sometimes, which render those batches untestable and unsafe in handling.

CCMB researchers found that VTM can be avoided totally. Dry swab technique also does not require the RNA extraction process, and can be directly used for RT-PCR testing with sensitivity and specificity similar to the current gold standard, CCMB said in a press release on Friday.

Dr Rakesh Mishra, director, CCMB says, “RNA extraction, even with automation, takes four hours for roughly 500 samples. VTM and RNA extraction both add a significant burden of money and timewise for mass testing of Covid-19 virus. We believe our 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.”

Dr Mishra terms it “a game changing technology” enhancing Covid-19 screening several fold with immediate effect and at the same time, making the whole process safer.”