A new CRISPR powered paper based COVID19 test “FELUDA” developed by CSIR IGIB and TATA is game changer in fight against COVID19

The new test named aptly as “FELUDA”, after a famous fictional Indian detective, uses state of the art combination of CRISPR technology. It is more accurate than a rapid antigen test and almost as quick. Priced at Rs. 500 and result delivery under 45 minutes, this test is able to differentiate SARS-CoV-2 from other coronaviruses.

The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) Feluda test, developed by the New Delhi-based CSIR-Institute of Genomics and Integrative Biology (IGIB) and the TATA Group, received regulatory approvals last week from the Drug Controller General of India (DCGI) for commercial launch.

The test was tested on 2000 patients, including ones who had already tested positive for the coronavirus. The results were highly encouraging. Researchers got 96% sensitivity and 98% specificity. 

A test that’s highly sensitive will detect almost everyone who has the disease; and a test that has high-specificity will correctly rule out almost everyone who doesn’t have the disease. The first ensures not too many false negative results; and the second not too many false positives. India’s drug regulator has cleared the test for commercial use.

Similar to a pregnancy strip test, Feluda changes colour if the virus is detected and doesn’t need expensive machines for detection.

“The CRISPR technology uses a highly specific CAS9 protein to find and bind to the target COVID signature. This is then coupled with paper-strip chemistry to elicit a visual readout on a paper strip,” Chakraborty explained.


The test can help the country, with the world’s second highest cases of COVID-19 at 70 lakh cases, ramp up testing of the disease quickly and economically, the researchers behind the test said in a statement.

FELUDA, an acronym for the FNCAS9 Editor-Limited Uniform Detection Assay, uses an indigenously developed, cutting-edge CRISPR technology for detection of the genomic sequence of SARS-CoV-2 virus. CRISPR is a gene editing technology and is used in correcting genetic defects and treating and preventing the spread of diseases. The technology uses specially enzyme called Cas9, which acts as scissors to cut at specific sites on DNA can change a single base or detect one. 

According to Dr.  Ray, Feluda is capable of detecting even low quantities of the genetic material of the novel coronavirus, based on very minute differences in their RNA – the genetic material of a virus

“It can distinguish between SARS-CoV-2 and SARS-CoV sequences which differ by a single nucleotide. Unlike RT-PCR which requires expensive machines, Feluda is simple and can be used in laboratories as well as outside with a quicker turnaround time” 

The CRISPR Feluda test is the world’s first diagnostic test to deploy a specially adapted Cas9 protein, derived from Francisella novicida bacteria, to successfully detect the virus that causes COVID-19

Other CRISPR tests, like the one developed in the US, use CAS12 and CAS13 proteins to detect SARS-CoV-2.

As compared o RAPID antigen tests which detect virus proteins and not very sensitive, FELUDA detects RNA and highly specific almost comparable to gold standard RT_PCR test. The RT-PCR test is laborious, requires trained manpower and expensive laboratory setup taking upto 2 hrs to hours to report.

Although, a South Korean company Labgenomics has developed a RT-PCR test called as Labgun Exofast COVID19 PCR Test which takes only 35 min! Siemens Healthineers India has partnered with Labgeomics to sell this highly accurate and fastest RT-PCR test in India. 

Feluda gives similar sensitivity and specificity as RT-PCR but is inexpensive, requires a basic widely available PCR machine and doesn’t require extensive trained manpower.

Sample collection for the Feluda test will be similar to the PCR test – a nasal swab inserted a few inches into the nose in the back of the nasal passage.

“This marks a significant achievement for the Indian scientific community, moving from R&D to a high-accuracy, scalable and reliable test in less than 100 days. The Tata CRISPR test achieves accuracy levels of traditional RT-PCR tests, with quicker turnaround time, less expensive equipment, and better ease of use,” the researchers said in their statement.

They described CRISPR as a futuristic technology that can also be configured for detection of other pathogens in the future.

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