With COVID-19 still circulating amongst the global population, widespread and time-efficient testing for its presence has been in great demand. This may now be met with a coronavirus test kit developed by scientists at the Nencki Institute of the Polish Academy of Sciences.
As part of the SONAR Anti-CoronaVirus project, the researchers developed procedures and recommendations for the size of the tested groups of people and the selection of test kits.
In this context, project leader Professor Agnieszka Dobrzyń told the Polish Press Agency (PAP): “we are ready to implement group testing. Our findings work, we tested them on 701 samples from patients positively diagnosed for the presence of the SARS-CoV-2 virus. The results are clear: group testing is a response to the demand for widespread testing.”
During the initial stages of their work, the Polish scientists assumed that a single test kit could be used to test as many as several dozen patients. This was corroborated by studies which have shown that even with a very low concentration of the virus in the sample, it is detectable with a collective test in a pool obtained from a combination of 30 people.
As their work progressed, the scientists introduced the value of an ideally short time and low cost under which testing could be carried out for the largest number of people. It turned out that such a group would consist of 12 individuals. Nevertheless, the size of such a group is contingent on the percentage of infected people in a given population. That is why scientists propose three different grouping methods.
“If the percentage of the infected in the population is below 2 percent, a single test kit will be sufficient for 12 samples. If it is higher than 2 percent but less than 8 percent, an 8x12 sample grid test is used. If it is 8 percent to less than 15 percent, a single test kit is sufficient for 4 people,” Professor Dobrzyń said, adding that “but if there is a risk that more than 15 percent of a given population may be infected, then pooled testing ceases to be feasible, and individual tests are better.”
In Poland, where the population amounts to 37,842,414 and the number of active cases as of Wednesday amounted to 11,712, the percent of the population that has been confirmed to be infected amounts to 0.03 percent.
The researchers say that group testing will be useful in screening tests to determine how widespread the virus is in a given population. “We should definitely include pooled testing in basic COVID-19 diagnostics, certainly in populations where we expect low percentages of those infected, in individual companies, factories, universities, schools and wherever we have a large population of people who must stay in one room,” Professor Dobrzyń said.
As part of the SONAR Anti-CoronaVirus project, scientists tested six PCR tests for the detection of SARS-CoV-2 virus available in Poland. The test results allowed for the recommendation of two, namely MediPAN developed in Poznań and Korean DiaPlexQ, both of which have a very high sensitivity.
Professor Dobrzyń said that “samples that could not be clearly identified using pooled testing contained less than two copies of the virus. They could have come, for example, from people at the very beginning of the infection or ending an asymptomatic infection. However, according to my observations, the most diluted samples were not skilfully collected. But this stage of the procedure can be easily improved.”
Pilot studies on selected populations of employees and students, which will confirm the effectiveness of their protocols, will begin shortly, with the hope that in the next stage, pooled testing will be implemented throughout Poland.
Professor Dobrzyń agrees with World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus that the lack of mass testing is like fighting fire blindfolded. She said: “Now we are extinguishing the fire where it has already broken out. With mass testing, we could extinguish this fire more effectively, before it spreads.”