Authorities in China have started to roll out anal swab COVID-19 tests, which they say will help detect cases in high-risk individuals.

Bloomberg reports that state-run channel CCTV said the anal swabs are currently being utilized for high-risk cases, because they can detect the virus more accurately than a throat swab. Additionally, it's believed that these tests do not appear to have a coordinated policy right now, and there's word that some people have been subjected to surprise tests. Among those allegedly receiving surprise tests include passengers arriving in Beijing, people living in quarantine centers, and as per local reports, over 1,000 school students and teachers who could have been exposed to the virus.

The tests require a medical professional or trained volunteer to insert a cotton-tip swab into the rectum. Li Tongzeng, the deputy director of the respiratory and infectious diseases department at Beijing You An Hospital, told state media that studies show the virus lasts longer in the anus or feces than the respiratory tract. That means the test is allegedly more effective at identifying people with the virus who might show only mild symptoms, or no symptoms at all.

The Washington Post reports that the introduction of anal swabs hasn't been well received by the country's citizens, with many expressing concern on Weibo. "Everyone involved will be so embarrassed," one user wrote, while a poll on the social media site indicated 80 percent "could not accept" the tests. 

"If we add anal swab testing, it can raise our rate of identifying infected patients," said Li Tongzeng. "But of course considering that collecting anal swabs is not as convenient as throat swabs, at the moment only key groups such as those in quarantine receive both."

The Lunar New Year season is just weeks away, and authorities have resorted to the anal swab method amid tightening restrictions. It is estimated that three billion or so trips are made during the holiday season in a typical year, raising concerns that even a single case could spark a dangerous outbreak.