Video by Liu Xudong

A negative nucleic acid test report is not only Shenzhen residents’ pass into public venues at the moment, but it also calms the nerves amid the raging COVID-19 pandemic.

Heráclito Everson Biscaia Filho, a Brazilian who has lived in Shenzhen for 14 years, joined Shenzhen Daily on Sunday to take a look behind the scenes at the steps involved in daily nucleic acid testing.

Filho waited in line for a nucleic acid test at a sampling location near the Ganlanpengyuan housing compound at Xintian Community in Huafu Subdistrict, Futian District. The site is one of the city’s many nucleic acid sampling locations.

The sampling site receives between 3,000 and 5,000 residents per day for nucleic acid tests, according to You Lyu, head nurse at the Massage Department, Shenzhen Hospital of Guangzhou University of Chinese Medicine.

Filho, like other residents, had to present his green health code and scan the site’s QR code to register for the nucleic acid test. He was given a tube containing an inactivated preservative solution. When it was Filho’s turn, the tube must be given to the sampling staffer.

Once Filho got his throat swab, the sample was placed in the solution-containing tube and then sent to the hospital’s in-house test lab.

“Every two hours, a staffer will come and collect samples and bring them back to the hospital’s lab for testing,” You explained.

At the test lab in Shenzhen Hospital of Guangzhou University of Chinese Medicine, all personnel must wear gloves and protective clothing. Lin Siqiang, a lab technician from the hospital’s clinical laboratory department, explained how the samples were tested and how they got the results.

According to Lin, the solution in the sampling tube contains guanidine salt, which can inactivate the virus and render it incapable of infection. To measure the amount of genetic material in a sample, the lab technician would add fluorescent dyes to the PCR (polymerase chain reaction) procedure.

“If a tube containing 10 samples yields a positive result, we will find out the 10 people and sample each of them separately to figure out whose specimen is positive,” Lin explained.

The testing results will be automatically uploaded to the provincial digital platform, which will generate the health codes, according to Lin. “Rapid testing results are required to come out within 90 minutes. In most cases, the results will be available within six hours.”

“I’m so impressed with the lab’s capacity to do so many tests in a single day, with results coming out in such a short time,” Filho said. “I’m really thankful for the frontline workers’ dedication and their long hours of work.”

Filho volunteered at a nucleic acid sampling site at Shekou in Nanshan District, on Saturday. “I have no doubt that Shenzhen will win this battle against COVID. As a citizen, we need to continue to do our part. We should show our gratitude to all the staff involved.”