Virologists from Germany have shown that combining samples and only testing individual samples if there is a positive result for the group could massively increase the capacity for coronavirus testing.
Testing has been a major limiting factor in the response to the COVID-19 pandemic.
Healthcare systems across the world have been struggling to cope with the demand for testing, with many countries having insufficient capacity even to test healthcare workers. Laboratory infrastructure is stretched and, in some cases, completely overwhelmed by the pandemic.
Scientists from Germany, which has had an admirable testing capacity, have published details of a testing strategy that they say could massively increase capacity in laboratories around the world.
The strategy involves pooling samples from multiple people and only testing individual samples if the result from the group test is positive. This could potentially save thousands of unnecessary tests.
The details now appear in The Lancet Infectious Diseases.
Testing is an essential part of the response to the pandemic. Germany’s high testing rates have been linked to the country’s lower death toll. Around 7,569 people have died of COVID-19 in Germany, compared with 31,930 in the United Kingdom and 30,560 in Italy. This is despite Germany having a larger population than both of these countries.
Knowing who has the virus is critical in preventing them from coming into contact with others, particularly among people who are most at risk, such as older adults and those with serious illnesses.
This is not simply a case of isolating people with symptoms, however, as people can carry the virus without experiencing any symptoms at all. People can also be contagious before the onset of symptoms — in fact, viral load is at its highest around a day before any symptoms appear — making diagnostic tests essential.
“Prevention is only possible if we use large-scale testing to identify asymptomatic persons and thus avert infection of the most vulnerable,” explains senior study author Prof. Sigrun Smola, director of the Institute of Virology at Saarland University Medical Center in Germany.
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