Staff members check the names of people involved in throat swab collection at a health observation point. Photo:Xinhua

How did Wuhan manage to test 9 million people within 10 days? Hospitals and testing agencies combined individual sample testing and grouped testing to increase test efficiency, sources told the Global Times.

Wuhan managed to test 9 million people from May 15 to 24, among whom 218 asymptomatic carriers were reported, said the local health authority.

A doctor in charge of testing from Wuhan's Zhongnan Hospital told the Global Times that they had tested 70,000 samples individually.

"Other hospitals and testing institutions test combined samples of five to 10 people together. If all test negative, the group will be deemed to have passed the examination; if they test positive for the virus, then the samples will be separated and tested individually," said the doctor who declined to be named.

"This is the only way to speed up the process, otherwise Wuhan cannot test as many samples within such a short time," Peng Zhiyong, director of the intensive care unit of the Zhongnan Hospital of Wuhan University, told the Global Times.

Peng said there was no problem with the accuracy of grouped testing. "Grouped sample testing is based on the presumption that the infection rate is under 1 percent; if the infection rate is above 5 percent, then grouped testing would be a waste of time and money," said Peng.

Hubei Daily reported that Wuhan currently has 63 nucleic test institutes, 386 sample collection spots, and has the capacity to test a maximum of 100,000 people on a daily basis.

The city's testing capacity has been improving since the city-wide test campaign was initiated. On the first day, 113,609 people were tested, and the number soared to 1 million on May 21, the seventh day of the campaign.

As the city-wide testing approached its end, many Wuhan residents posted their negative nucleic test results on social media. One Wuhan resident named Luo Ning said "friend, I am negative for the virus. You can be assured it's safe to hang out with me."

Even though the lockdown was lifted on April 8 and the risk level has been lowered, the city's vitality has yet to return, with many restaurants and buses still empty, Yang Zhanqiu, a deputy director of the pathogen biology department at Wuhan University, told the Global Times.

"The massive testing will make Wuhan a safer place and let the outside world know about the city's real situation," said Yang, who added that it is a sign that Wuhan is taking the initiative in fighting the virus. "It's like a war. You take the initiative, you win."