Coronavirus Testing: CCMB develops dry-swab testing method for COVID-19
The problem with the current COVID-19 sample collection method using Viral Transport Medium (VTM) is the potential for further spread of the virus. The dry swab technique is safe, fast, cheap, and more accurate. Know more.
Rakesh Mishra, Director of Center for Cellular and Molecular Biology (CCMB) on April 30, 2021, said that they devised a new dry swab technique for collecting COVID-19 samples.
Mishra called the newly discovered dry swab technique safe, fast, cheap, and more accurate compared to existing methods of COVID-19 sample collection. He also highlighted that with the dry swab technique, we can expect a 300 per cent increase in the testing capacity on daily basis.
Mishra spoke about the potential hazards and the drawbacks of the current process of COVID-19 sample collection using Viral Transport Medium (VTM).
Sample leakage and cross-contamination
Currently, the samples are collected using nasal and throat swab and put in a tube containing pink colour liquid called Viral Transport Medium (VTM) and sent further for processing.
Rakesh Mishra explained that the problem with the current COVID-19 sample collection method using Viral Transport Medium (VTM) is the potential for further spread of the virus.
“If the container that has the swab and the sample is not properly sealed, there might be a leak. As these samples may potentially contain the virus, they might lead to the further spread of the virus and cross-contamination,” he explained.
Time-consuming and expensive process
Secondly, the current process of sample collection is time-consuming. It requires around 2 to 3 hours to unseal 200 to 300 sample tubes.
Next, the RNA extraction of the samples is not only time-consuming but expensive too.
Then, the whole process of the RT-PCR test consumes more time before returning tests results.
What is the dry-swab technique?
The dry swab technique of COVID-19 sample collection involves taking a nasal swab and transporting it in the dry state unlike the process using the viral transport medium.
Mishra explained the various advantages of the dry swab technique such as no fear of spillage of the sample, or spread of the virus, cost-effective and quicker turnaround time to process results.
No spillage of samples and cost-effective
In the dry swab technique, the samples are not required to be kept in VTM instead they can be stored in a dry container and sent to the labs.
The dry swab sample is placed into a TE Buffer, a cost-effective buffer solution.
Safe, faster, and accurate
The samples placed in TE Buffer become ready for the RT-PCR test in just about 30 minutes. With dry swab, there is no RNA extraction which in turn saves more time and generates test results quicker.
He mentioned that the chances of error with the dry swab technique compared to the process using VTM are incredibly low.
The accuracy level of the dry swab technique is the same as the RT-PCR test which is around 80 per cent.
Increased capacity of testing
The dry swab technique can boost up the number of tests being currently conducted by 300 per cent every day. This can help in conducting more tests quickly and accurately on daily basis across the country, he said.
Mishra informed that the dry swab technique has received approval from the Indian Council for Medical Research (ICMR) and has been implemented in many labs for testing across the country.
He further mentioned that the license for the dry swab technique is being sold to various hospitals, private companies and labs so kits can be set up after getting the permits from the Drugs Controller General of India (DCGI).