A National Health Commission official said that authorities have revised guidelines on COVID-19 nucleic acid testing to speed up the process of controlling potential sources of infection more quickly and effectively.

Jiao Yahui, director of the commission's Bureau of Medical Administration, told a news conference on Tuesday that the revised guidelines required that testing in certain areas should be completed within 24 hours, rather than 48 or 72 hours previously stipulated.

"The change was made based on the Omicron variant's ability to spread faster and its ability to mask its presence," she said.

"Also, we have changed 'mass testing' to 'regional testing', meaning that we will designate areas where people need testing in a more scientific and accurate way," she said, adding that such designations will be based on local conditions of epidemic prevention and control.

Jiao said that the revisions are based on the successful practices in places like Zhengzhou in Henan and Xi'an in Shaanxi, where during recent outbreaks, the entire city was tested within 24 hours.