Tools to identify infections as cities reduce nucleic acid test requirements

COVID-19 antigen self-testing could be an important tool for identifying and managing infected people and preventing the virus' spread to highly vulnerable groups, experts said as more cities cut back on nucleic acid testing.

Feng Zijian, vice-president of the Chinese Preventive Medicine Association, said during an interview with ThePaper.cn, a Shanghai-based media outlet, that people who feel they might be at risk of being exposed to the virus can opt to take rapid antigen tests.

He made the suggestion as the National Health Commission banned the arbitrary rollout of mass testing and a number of regions have waived regular testing requirements as a condition for taking public transportation or entering public places.

"Large-scale nucleic acid testing is a very convenient approach to detecting infections, and reducing testing services will likely affect the ability to halt the virus' transmission and cause a spike in new infections," he said. "Under such a circumstance, self-testing is a significant alternative."

It is widely believed that nucleic acid COVID-19 tests are more accurate than antigen tests. Li Jinming, deputy director of the National Center for Clinical Laboratories, said during a news conference in March that antigen test kits in China have a sensitivity of 75 to 98 percent and a specificity of 95 to 99 percent, meaning that their negative results are largely reliable but a percentage of positive test results could be false.

Li Tongzeng, a doctor at Beijing YouAn Hospital affiliated to Capital Medical University's respiratory and infectious disease department, said antigen test kits can be self-administered at home and can return results within 15 minutes, while nucleic acid tests must be processed in laboratories and take four to six hours to provide a result.

"People reporting symptoms of COVID-19 disease can get an initial diagnosis via antigen tests," he said during an interview with People's Daily.

However, nucleic acid testing remains the gold standard for diagnosis and individuals whose antigen test results are positive should report to communities immediately.

He also suggested stocking some antigen test kits at home as experiences overseas have shown that in the future, antigen testing could play a large role in coping with the disease.

According to the National Medical Products Association, the mainland had approved over 30 different makes of COVID-19 antigen test kits.