Researchers develop new COVID-19 test that doesn't use scarce reagents
Washington: Scientists have developed a new method of testing for COVID-19 that doesn't make use of key reagents but still delivers an accurate result, an advance that may lead to an inexpensive diagnosis technique in developing countries where chemical supplies are in short supply.
The method, described in the journal PLOS Biology, omits the step in the widely used reverse transcription polymerase chain reaction (RT-PCR) test where the scarce reagents are needed, but has an accuracy of 92 per cent, missing only the lowest viral loads.
The researchers, including those from the University of Washington in the US, tested the new method using 215 COVID-19 samples that RT-PCR tests had shown were positive, with a range of viral loads, and 30 that were negative.
They said it correctly identified 92 per cent of the positive samples and 100 per cent of the negatives.
While the positive samples the new test failed to catch had very low levels of the virus, the scientists said ultra-sensitive tests that identify individuals with even the smallest viral loads may not be needed to slow the spread of the disease.
"It was a very positive result," said Jason Botten senior author of the study from the University of Vermont in the US.
"You can go for the perfect test, or you can use the one that's going to pick up the great majority of people and stop transmission," Botten said.
While standard PCR tests have three steps, the version developed by the researchers has only two, the study noted.
"In step 1 of the RT-PCR test, you take the swab with the nasal sample, clip the end and place it in a vial of liquid, or medium. Any virus on the swab will transfer from the swab into the medium," Botten said.
"In step 2, you take a small sample of the virus-containing medium and use chemical reagents, the ones that are often in short supply, to extract the viral RNA. In step 3, you use other chemicals to greatly amplify any viral genetic material that might be there. If virus was present, you'll get a positive signal," he explained.
In the new method, Botten said, a sample of the medium that held the nasal swab is taken directly to the third, amplification step, removing the need for scarce RNA extraction reagents as well as significantly reducing the time, labour and costs required to extract viral RNA from the medium in step 2.
According to the researchers, the test is ideally suited to screening programs, in both developed and developing countries, since it is "inexpensive, takes much less processing time, and reliably identifies those who are likely to spread the disease."
Its low cost and efficiency could extend testing capacity to groups not currently being tested, including the asymptomatic, nursing home residents, essential workers and school children, Botten added.
He said the standard RT-PCR test could be reserved for groups, like health care workers, where close to 100 per cent accuracy is essential.
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Deputy CM Shivakumar announces property ownership drive in Bengaluru
Bengaluru (PTI): Karnataka Deputy Chief Minister D K Shivakumar announced a major property ownership drive here aimed at correcting and regularising property records, saying the government had already rectified 23 lakh Khatas and enabled citizens to download their documents online.
Shivakumar, who also holds the Bengaluru Development portfolio, said the state government had begun converting B-Khatas into A-Khatas and would organise special Khata camps every Saturday across corporation limits from May 16 to help citizens secure their property documents.
A Khata is a legal document in Bengaluru certifying that a property complies with all local by-laws, regulations and has paid property taxes to the civic body.
“We have already corrected 23 lakh khatas and provided an opportunity for people to download them,” he said.
Shivakumar explained that the major campaign has been undertaken in Bengaluru to streamline property documentation.
The Deputy Chief Minister said between five and 10 centres would be set up in every corporation area as part of the “Khata Andolana” programme and urged citizens to participate in large numbers.
“I appeal to people to safeguard their property documents. We have created an opportunity for all citizens,” he said.
Calling it a "people-centric" initiative, Shivakumar said the government was working to ensure citizens received proper ownership documentation for their properties.
Shivakumar further claimed that the initiative had drawn national attention and said the Union government had recognised Karnataka with an award for the programme.
“Your Khata is your right. Obtain your Khata and protect yourself from fraud,” he said, while urging people to take advantage of the scheme.
