New Delhi: Scientists in Israel have developed a new Covid-19 testing procedure that can test pools of as many as 48 samples at once.
Developed by researchers from Ben-Gurion University of the Negev, the method accurately screened 1,115 health care workers with just 144 tests.
The standard RT-PCR tests takes several hours to be processed. This, combined with the time taken to collect and transport samples, means the result may sometimes take over a day to come. But pool testing has come to be a preferred method in low-prevalence areas for its efficacy.
If a pool tests negative, then the need for conducting separate tests again is eliminated. However, if the pool tests positive, it means that one of the samples is Covid-19 positive. Further tests are then conducted to determine which patient is positive.
Called P-Best, for Pooling-Based Efficient SARS-CoV-2 Testing, Israel’s method is based on an algorithm that is used to detect rare genetic mutations. For example, the team took samples of 384 people and divided them into 48 pools in such a way that each person’s sample ended up six different pools.
Each of the 48 pools was then tested. If one person tested positive for the virus, then each of the six pools containing that sample should test positive. A unique combination of positive pools would then reveal the identity of the infected person.
The method however becomes less effective if the prevalence of Covid-19 in the population is too high.
The method has been approved for clinical use by the Israeli health ministry and the country’s government now plans to roll out it out across Israel by October.
Israeli authorities and researchers are now working with an artificial-intelligence company to process the results and cull out samples that have a higher likelihood of being positive, based on coronavirus hotspots.
Several countries, including India, have already used the concept of pool testing. The Indian Council of Medical Research (ICMR) guidelines recommend carrying out such tests in areas that have a low prevalence of Covid-19, and India’s pool testing method can screen only up to five samples at a time.
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