In this file picture, a man gets tested for Covif-19 at Ga-Rankuwa Shopping Centre.Picture: Oupa Mokoena/African News Agency (ANA)
In this file picture, a man gets tested for Covif-19 at Ga-Rankuwa Shopping Centre.Picture: Oupa Mokoena/African News Agency (ANA)

Wits creates formula that improves accuracy, safety of Covid-19 testing

By Chulumanco Mahamba Time of article published Nov 5, 2020

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Johannesburg - A team from Wits University’s Centre for Biomedical Tuberculosis Research (CBTBR) has developed a solution to improve the accuracy and safety of Covid-19 testing.

The team, headed up by Professor Bavesh Kana and his team, Dr Edith Machowski, Dr Bhavna Gordhan and Dr Christopher Ealand, has developed a unique “control standard” to ensure that testing is independently verified as to assure its accuracy.

According to the university, what makes the solution unique is that it uses biomimicry, a safer alternative to incorporating the actual Sars-CoV-2 virus.

The team used the biomimicry technique to engineer a control organism that mimics the genetic material of the virus when used in diagnostic tests kits.

“If the tests work correctly, the genetically modified organism is identified as being Sars-Covid-2.

“This control is safe, non-pathogenic, i.e. non-disease causing, and stable,” the university said.

Kana told The Star on Wednesday that it was important to understand that the team did not create a test kit.

The professor said the gap the team was addressing was that all labs needed to ensure what they are doing are accurate, and quality assured.

“For this, one needs to use the actual disease agent in mock tests (not from patients) to ensure that the diagnostic kits are working and that lab staff are processing the specimens correctly.

“The challenge is that we cannot send the Covid virus to labs, as it is dangerous. We need something else that will read as a positive result in the test,” he said.

Speaking on how the solution could be administered at the laboratories and clinics, Kana said lab staff could run some tests with the team’s controls, which read as Sars-CoV-2 positive, and check if the results are as expected.

“If the results are correct, we know that the staff are processing the patient specimens correctly. This is an incredibly important step to ensure that people can have confidence in their diagnosis,” he said.

He added that when new diagnosis tests are being set up on a lab, the labs require samples that they know are positive to calibrate and check if the new tests work.

“One way of approaching this is using samples from patients that have tested positive. However, these samples are not always available and can give variable results.

“Our controls allow the labs to test new kits without the need for infectious virus or patient specimens,” he said.

Kana said that accuracy testing controls were central to the deployment of any successful diagnostic test.

“Without appropriate controls to report whether tests are delivering the correct result, diagnosing and effectively managing Covid-19 will be very difficult, if not impossible,” the professor said.

The team has previously contributed to the development of biomimicry based control standards for diagnostics for drug resistant tuberculosis (TB), which are now deployed in more than 20 countries internationally.

The Star

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