COVID-19: India's paper-based coronavirus test could be a 'game changer'!

• The BBC reported that Feluda will be made by leading Indian conglomerate, Tata.

A team of scientists in India has developed an inexpensive paper-based test for coronavirus that could give fast results similar to a pregnancy test, according to a BBC report.

The test, named after a famous Indian fictional detective, is based on a gene-editing technology called Crispr (Clustered Regularly Interspaced Short Palindromic Repeats). Scientists estimate that the kit - called Feluda - would return results in under an hour and cost 500 rupees.
The BBC reported that Feluda will be made by a leading Indian conglomerate, Tata, and could be the world's first paper-based Covid-19 test available in the market.

"This is a simple, precise, reliable, scalable and frugal test," Professor K Vijay Raghavan, principal scientific adviser to the Indian government, told the BBC.


Researchers at the Delhi-based CSIR-Institute of Genomics and Integrative Biology (IGIB), where Feluda was developed, as well as private labs, tried out the test on samples from about 2,000 patients, including ones who had already tested positive for the coronavirus.

They found that the new test had 96 per cent sensitivity and 98 per cent specificity. The accuracy of a test is based on these two proportions. 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.

With more than six million confirmed infections, India has the world's second-highest Covid-19 caseload. More than 100,000 people in the country have died of the disease so far.

After a slow start, India is now testing a million samples a day in more than 1,200 laboratories across the country. It is using two tests.
The first is the time-tested, gold standard polymerase chain reaction, or PCR swab tests, which uses chemicals to amplify the virus's genetic material in the laboratory. The second is the speedy antigen test, which works by detecting virus fragments in a sample.

The PCR test is generally reliable and costs up to 2,400 rupees. It has low false positive and low false negative rates. The antigen tests are cheaper. They are more precise in detecting positive infections, but generate more false negatives than the PCR test.

Scaling up testing in India hasn't meant easy availability yet, according to Dr Anant Bhan, a researcher in global health and health policy.
"There are still long wait times and unavailability of kits. And we are doing a lot of rapid antigen testing which have problems with false negatives," Dr Bhan told the BBC.

He believes the Feluda test could potentially replace the antigen tests because it could be comparatively cheaper - and more accurate.
"The new test has the reliability of the PCR test, is quicker and can be done in smaller laboratories which don't have sophisticated machines," Dr Anurag Agarwal, director of IGIB, told the BBC.

Sample collection for the Feluda test will be similar to the PCR test - a nasal swab inserted a few inches into the nose to check for coronavirus in the back of the nasal passage. India still doesn't allow Covid-19 tests from saliva samples.

In the traditional PCR test, the sample is sent to an accredited laboratory where it has to go through a number of "cycles" before enough virus is recovered.

The new Feluda test uses Crispr or a gene-editing technology to detect the virus.