A group of Indian researchers created a cheap paper-based test for coronavirus that could provide results fast as a pregnancy test, using gene-editing technology. The test, called Feluda after a famous Indian fictional detective, would give results in an hour and cost about $6.75.

Feluda will be manufactured by a leading Indian company, Tata, and could become the world’s first paper-based Covid-19 test available in the market. It’s simple, precise, reliable, and scalable, according to Professor K Vijay Raghavan, principal scientific adviser to the Indian government, speaking with the BBC.

The test was developed by researchers at the Delhi-based CSIR-Institute of Genomics and Integrative Biology (IGIB), working with private labs. They first tried Feluda on samples from about 2,000 patients, including some who had already tested positive for the coronavirus.

They found that the test had a 96% sensitivity and 98% specificity. A highly sensitive test can detect almost everyone who has the disease, while a high-specificity test can rule out everyone who doesn’t have the disease. The first one rules false negatives and the second one false positives.

India’s drug regulator already authorized the test for commercial use. The country is the world’s second-highest in confirmed infections of COVID-19, now exceeding six million. More than 100,000 people have already died of the disease. The country is now testing a million samples a day, using two different tests.

One is the time-tested, gold-standard polymerase chain reaction, or PCR swab tests. It uses chemicals to amplify the virus’s genetic material in the laboratory. The other one is the speedy antigen test, which works by detecting virus fragments in a sample. The PCR test is reliable but expensive, while the antigen is cheaper but generates more false positives.

Dr. Anant Bhan, a researcher in global health and health policy, told BBC that there are curently long wait times and unavailability of Feluda kits across the country. However, he argued it could end up replacing the antigen test as it is cheaper and more accurate.

The sample collection for Feluda will be similar to the PCR test, using a nasal swab inserted a few inches into the nose to check for coronavirus in the back of the nasal passage. Feluda uses CRISPR, Clustered Regularly Interspaced Short Palindromic Repeats, a gene-editing technology to detect the virus.

Several companies in the US and the UK are working on similar paper strip tests that can be cheap and mass-produced. One of the most mentioned has been a paper-based strip developed by Sherlock Bioscience, already approved for emergency use by the US Food and Drug Administration (FDA).

“The ideal and ultimate test will be the one that is paper-based which you can do from home,” Dr Thomas Tsai of the Harvard Global Health Institute told BBC News. “But of course, there are some biological restrictions to the technology – we can’t expect people to extract and amplify the RNA from home.”