Anal swabs for covid risk cases. Chinese health authorities have begun to use the new tests to check people at greatest risk of contracting the coronavirus. This was reported by the state broadcaster CCTV, reporting that the test has already been used for passengers arriving at the Beijing airport, in the quarantine centers and on a group of over a thousand students and teachers for whom the exposure to the virus. The test, reserved for high-risk cases, involves inserting a 2.5-5 cm swab into the rectum, which is then tested to check for the presence of the virus. This test is believed to be more accurate for identifying disease in people who have mild symptoms or are asymptomatic.