Indian Council of Medical Research (ICMR) on Wednesday issued a second advisory regarding using the RNA extraction free dry swab method for the RT-PCR-based detection of SARS-CoV-2 developed by CSIR-Centre for Cellular & Molecular Biology (CCMB), thereby clearing the path for more usage of this faster testing method.
The development comes in the wake of the current surge of cases in the pandemic. The dry swab method will save time and reduce cost as compared to the standard PCR test using Viral Transport Medium (VTM) and RNA extraction. This would help in increasing the testing “three fold with existing resources” and since it is as good as the standard test, according to senior scientists.
ICMR had conducted two validations of the dry swab method in August and November 2020, respectively. The dry swab method involves collection of a VTM (imported and expensive virus transport medium) less dry oropharyngeal / nasopharyngeal swab from suspected patients.
It is distinctly safer and convenient for healthcare workers as no liquid handling is involved. The swab is then transported to the lab. Thus, the sample can be directly isolated from the patient swabs, and testing using a one-step protocol. In comparison, the current gold-standard RT-PCR method requires many expensive reagents and steps that add to the expertise, money and time required for the tests.
Senior scientists have stated that the dry swab or DArRT-PCR test reduces the time and human effort by 40-50% in the current setting of testing.
ICMR in the latest advisory states that if a sample comes out as positive after a dry swab test, it has to be reported as such and inscribed in the online database.
However, if the dry swab test indicates negative for a person with symptoms, a repeat dry swab test with standard RT-PCR test is recommended.
CCMB has tied up with Apollo Hospitals, Spice Health and Meril Life Pvt Ltd. for commercially upscaling the dry swab testing method across diagnostic labs in the country.
