New Low-Cost Coronavirus Test Developed By CCMB Scientists
Reverse transcription-polymerase chain reaction (RT-qPCR) test is the only recommended test for COVID-19 by the Indian Council of Medical Research (ICMR). Now the scientists at CSIR’s Centre for Cellular and Molecular Biology (CCMB) have developed a new test for the novel coronavirus that requires low-tech as well as low-cost. The new test has been named as reverse transcription nested PCR (RT-nPCR) test.
A real-time quantitative RT-PCR is not required for this new test. And it has shown performance comparable to the standard RT-qPCR tests. The RT-nPCR uses standard RT-PCR instead of RT-qPCR, as a part of an endpoint assay.
While comparing the results from the new test to the conventional RT-qPCR tests, researchers found that due to low viral representation in many samples, RT-qPCR tests have low detection efficiency (less than 50%) in a real testing scenario. This suggests the importance of monitoring the detection efficiency of coronavirus tests in the actual testing scenario.
The CCMB scientists developed and tested RT-nPCR protocol for amplification of four COVID-19 virus amplicons and a control human amplicon, followed by a secondary nested PCR for individual amplicons. They also tested the new low-cost coronavirus RT-nPCR testin pooled testing and in the direct amplification without RNA isolation.
They compared the RT-nPCR test results of nasopharyngeal swab samples with their previous results from the standard RT-qPCR test. The new coronavirus test was able to identify 90% of the positive samples detected using RT-qPCR test as positive.
The RT-nPCR test was also able to detect 13% of false-negative samples from RT-qPCR tests as positive. Studies show 50% of positive samples miss detection in single pass testing by RT-qPCR in an actual testing scenario.
ICMR is yet to approve the new RT-nPCR test for COVID-19. Dr. Mishra said this new test could be used in places where there are no RT-qPCR machines.