A low-cost, probe-free RT-PCR COVID-19 detection assay developed by IIT Delhi will be launched tomorrow (July 15). The assay does not require a probe as it uses a fluorescent dye. The results will be known immediately.

A probe-free RT-PCR COVID-19 detection assay developed by Indian Institute of Technology (IIT) Delhi will be launched tomorrow. The assay was developed by a team led by Prof. Vivekanandan Perumal of the Kusuma School of Biological Sciences, IIT Delhi. The assay was validated by ICMR and was found to have 100% sensitivity and specificity. It is being manufactured by a Delhi-based company.

“This IIT Delhi technology should change the paradigm of COVID-19 testing in the country, both in terms of scale and cost. This product, approved by ICMR and DCGI, is being launched tomorrow [July 15]. Two million tests at an unbeatable price,” Prof. V. Ramgopal Rao, Director of IIT Delhi tweeted.

On April 23, Prof. Rao tweeted saying “ICMR today approved the probe-free COVID-19 detection assay developed at IIT Delhi. This is expected to bring down the cost of detection to below Rs.300 in the country”.

The assay has been licensed to multiple companies. The Delhi-based Newtech Medical Devices will offer the kit under the ‘CoroSure’ brand. Genei Laboratories in Bengaluru is one of the other companies which has received the non-exclusive license from IIT Delhi to manufacture the probe-free RT-PCR detection assay.

“The assay does not require a probe as it uses a fluorescent dye. It is difficult and expensive to make a custom-synthesised probe. So, we got around the problem,” says Prof. Perumal.

The assay has a special primer that helps in amplifying the DNA after reverse transcription. “The primer, which is cheap and custom-made, amplifies only the novel coronavirus,” says Prof. Perumal. “Designing and optimising the special primer that selectively amplifies only SARS-CoV-2 was the challenge.”

The primer targets specific regions of the virus that are well conserved. Since the specific region in the Spike protein gene to which the primer binds is not seen in other viruses, only the novel coronavirus gets amplified. The primer was tested using real-time PCR. When the coronavirus DNA is amplified, the fluorescent dye binds to the amplified DNA and allows for real-time monitoring.

“As long as there is amplification, there will be fluorescence, which can be monitored real-time,” he says. “This allows us to get the results immediately.”

According to Prof. Perumal, one plate containing 96 samples can be tested in 80 minutes. This includes the time taken for reverse transcription and amplification.

The team did not use the actual virus for developing and testing but instead used synthetic DNA constructs of the virus and then generated RNA fragments in vitro.

IIT Delhi had got the assay validated by ICMR. In addition, Newtech had also got samples tested by ICMR. “We got one batch of 500 samples tested by ICMR,” says Jatin Goyal, Managing Director of Newtech. According to Mr. Goyal, 50,000 tests have already been manufactured, and the company has the capacity to manufacture two million tests per month.