Chinese health authorities in the city of Qingdao are batch testing to speed up a citywide mass Covid-19 testing program, the municipal government said on Wednesday.
The testing method combines 10 samples at a time; if any batch turns out positive, all 10 people are then quarantined and tested individually.
Batch testing is efficient; Qingdao, which reported 12 locally transmitted cases over the weekend, has already tested more than 7.5 million people, said Municipal Deputy Director Chen Wansheng. The city has a population of about 9 million.
"We need to test the entire population within five days," said Zhang Huaqiang, deputy director of the Qingdao Center for Disease Control and Prevention. "Our workload is very large, and our time is very tight."
So far, 4 million of the cases have shown negative results, and no new infections have been identified.
Questions about effectiveness: However, a Hong Kong medical expert has questioned the effectiveness of the mass testing program in identifying cases.
Dr. Jin Dongyan, a virology professor at the University of Hong Kong, told CNN on Wednesday that the test was "a waste of resources" in many situations because Covid-19 patients are usually identified over a range of time, and hidden cases cannot be identified at once.
"This is just a snapshot, so it definitely will miss a lot of positive individuals," he said.