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‘RTLAMP test is a game-changer in Covid-19 testing’

Published

8:18 am IST

on

Covid-19

Dr Ashutosh Sharma, Secretary Dept Of Science & Technology, speaks to NewsX’s Managing Editor on an indigenously developed kit that would be cheaper and tests could be done in no time.

Q. Can you tell us about the concept of an indigenous testing kit that I am told can do the test in a matter of minutes, is far cheaper. How is this being developed, where is this being developed?

A. This is indeed very positive news. Testing at a large scale and speed is one of the requirements today. So, what we need is a test that can give us the results quickly and inexpensively, and that is what Sree Chitra Tirunal Institute for Medical Sciences & Technology in Thiruvananthapuram is doing. We have a biomedical research wing that was set up about 4 years ago to make biomedical devices, because India imports a lot of them. And this was an opportunity to build on that platform. The test is called RTLAMP. The test we use currently is called RTPCR. RTPCR is the gold standard in testing, which means you can’t get false positives or false negatives with it. Hundred per cent accuracy. This particular test (RTLAMP) is equally accurate. It has no false positives, no false negatives. The score of RTLAMP tallies 100% with RTPCR. This is a very unique experiment for India. In fact, it is among the first in the world.

Q. Does this (RTLAMP) also require an RNA sequencing machine?

A. It is not a sequencing machine. There is a gene and there are 2 sequences in that gene, called N-gene. It picks up 2 fragments which are unique signatures of the virus. So, if you match both of them, this is basically the SARS-Cov2 virus. It’s a confirmatory test, you don’t need any test before or after. Once you’re done, you know whether you have the virus or not.

Q. How is this particularly different from the RTPCR test?

A. The sample preparation is similar, but there is also a new innovation here. So, you can make it much faster and more concentrated in removing RNA from there. First, you break the virus, deactivate it, and then remove RNA from there, and concentrate it so that the test can go faster. The way you concentrate RNA is an interesting innovation. You put in magnetic nanoparticles, which go and stick to the RNA fragments. Using a magnet, you can pull all RNA fragments in one place.

Q. Are the magnetic nanoparticles actually sticking to the particular part of the RNA which is distinctive for nCov2?

A. No. They’re basically pulling the entire RNA strand. They’re sticking to the RNA strands and can be pulled in one corner, hence concentrating it. Once you start with something concentrated, you can amplify it. The amplification process in this is much faster. The detection of these two domains, the fragments of the gene which are unique to the virus, is much faster. In about 10 minutes, you get a confirmatory test. The whole process takes about 2 hours. This is different from PCR, where the test in itself takes several hours. In this particular platform, on the other hand, you can do 30 tests together. In 10 minutes, you have 1 machine, and you have 30 tests. Imagine in a day, if you’re running 2 shifts or 3 shifts, you’re running about a thousand samples – in 1 day and using 1 machine.

Q. Will the machine be different, or is it the same machine?

A. No, it is a completely different machine. It’s based on fluorescence, and the amplification process is different, which is why it’s faster. It starts with a more concentrated RNA soup. There are a whole lot of things which basically add up to the speed. The great thing about this is it’s never been done before. The reason they could do it before anyone else in the world is because they were testing this platform for TB diagnosis. Before the virus came around, they were already working on this platform. They had developed it, but they were looking at the rapid diagnosis of TB.

Q. Is that the magnetic nanoparticle side – was that the test that was happening for TB?

A. No, this is a platform for TB testing which is looking at the sequence of genes. It’s a different sequence for every microbe, bacteria, virus. It’s a different signature which you have to pick up. The same platform was prepared with a few changes and tweaking. We already had the infrastructure and people in place.

Q. What is the next step?

A. ICMR refers any new test to National Institute of Virology. They ran more than 50- 100 samples on it. They then validated this test against RTPCR. The report has now gone back to ICMR, they’re working to give formal approval on it.

Q. How much of a game-changer would this be?

A. There is already a tie-up with a company. Several more companies are coming on board to have greater scale. By the end of May, we should have 500 machines functioning. Which means 1,000 tests per day from 500 machines. Five lakh tests per day will be possible by the end of May. By the end of June, there will be at least 1,000 other machines. The cost of the machine is about Rs 2.5 lakh and may go down further. The cost of PCR is Rs 15 lakh and upwards, and PCR does about 15 tests a day. Imagine that versus 1,000 tests a day. For the cost of a PCR machine, you get seven of these test machines.

Q. You said it will take a month to scale to 1-2 lakhs per day. How much can we do within a more reasonable timeframe?

A. In a day, we have to really push it, in 2-3 shifts. We would do a 1,000 tests per day on a single machine. If you have a hundred machines, that’s 1 lakh tests per day. So, 7 lakh tests in one week will be tested by 100 machines.

Q. Our current testing capacity has just touched the 40,000 mark. That gives us perspective of how much value addition this would be.

A. You could even use this test before flying. There are multiple applications for this test. It can be used on people getting into crowded spaces, they could be prevented from transmitting the disease.

Q. Does the sampling procedure use a cotton swab?

A. Yes. The sample is collected the same way. Even here, there is innovation. The sticks that we use are mostly imported. Now, they’ve been designed with a polymer which has the right kind of flexibility. All of it is going to be made in India. Q. When did this project start?

A. They started looking at it about 3-4 weeks ago. They were optimistic. We told them – look, you already have the capacity, the people, the technology, the platform. Why not just put in this virus in there? And I think it worked. They worked very hard on it. It is very important to have the right people and the right knowledge base. Everything came together in this case.

Q. Is there any key part or key technology that can still be a stumbling block?

A. Few of these parts have to be imported, but we are tying up all of those supply lines. We are also approaching MSMEs and other people in the country to see if they can make these parts. These things have a global supply chain. Everything high-tech that any country makes, there are always some parts that are imported. Because they aren’t used in large numbers. It’s not because of technology, we could make these parts. The country didn’t make them because they probably weren’t required in large numbers before this. But once you have a good market, somebody will make them.

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