Companies in Wuhan are requiring employees to draw blood or have their throats swabbed before returning to work, reflecting the high level of anxiety that remains in the Chinese city as it emerges from a months-long lockdown.

Workers at Kone Elevators Co. queued in front of their office building in Wuhan’s eastern district on Thursday to take tests to determine if they have the coronavirus or its antibodies. The tests were being conducted by a private medical organization with the fees covered by Kone.

“We are not resuming work until we receive the negative results of all workers,” said Ke Jianjun, a company official helping to oversee the exercise as workers in protective suits took samples from dozens of employees under a makeshift tent. “We cannot take the risk of restarting business if anyone is infected or suspected.”

Wuhan emerges from lockdown with a mission: Our goal is survival

Kone is among many companies requesting mass testing of workers amid a fear of a resurgence of infections that’s hampering the city’s post-pandemic reopening. Ke estimated 6,000 tests would be conducted on Thursday.

As companies are allowed to resume work in Wuhan, they’re caught between pressure from the government to resume work and the risk of a second wave of infections. Memories are still vivid of how rapidly the virus overwhelmed the city two months ago, crippling its hospitals with desperate patients who couldn’t get tested.

The epicenter is still detecting cases of new infection in people who carry the virus but show no outward signs of being sick.

Wuhan’s reopening is being watched by other cities for lessons on how resumption of normal life after a lockdown is possible. Yet tactics such as the blood and spit tests for workers aren’t likely to be adopted in Western cities because of privacy concerns. It’s unclear if the Chinese government is collecting the data being generated by these tests.

Workers are being subjected to two tests: one that uses a specimen taken from their nose or throat to detect the coronavirus, and one that uses a blood sample to determine if they have COVID-19 antibodies. The latter could indicate the person had been infected with the coronavirus, recovered and developed some immunity, even if they were asymptomatic.

Demand for this kind of mass testing of workers started to increase in mid-March, when business in the city gradually resumed before the lockdown was fully lifted. Companies are already required by the local government to disinfect their factories daily and prepare sufficient protective supplies for their employees.

On top of that, state-owned enterprises, construction operators and other labor-intensive businesses have set up on-site testing centers run by private companies including UniMedLab, a gene testing institution.

“Appointments are fully booked for the next four days,” Zhu Jinhua, a UniMedLab saleswoman, said by phone. “People come to us because they are still trying to stay away from hospitals.”

A company could be told to halt production immediately if an infection is found among the employees, who are also concerned about getting infected by their co-workers, according to Zhu. “Both sides can’t afford the risk” not to test, she said.

Zhu said they charge no more than 300 yuan (US$43) for double testing, with results available in 24 hours, depending on the number of tests ordered. It costs about 480 yuan for the same service at public hospitals.

Auto parts company Digit Stamping Technology Wuhan Co. said it ran both tests shortly after its 226 workers returned from scattered places throughout the country.

“We do this for our own safety, it’s not a forced act by the government,” said sales department manager Gong Jinqian.