China has no started collecting anal swabs to detect COVID-19 infection in some high-risk groups.
Anal testing has already been conducted on selected groups, mainly high-risk groups and people who are in quarantine.
People who have undergone anal testing include passengers arriving in Beijing and over 1,000 schoolchildren and teachers who were believed to have been exposed to the virus, according to Forbes.
Collecting anal swabs for COVID-19 testing is limited because it is invasive and inconvenient.
If a stool sample cannot be obtained, a saline-soaked cotton swab about 1-2 inches long is inserted into the anus, with the sample tested for active traces of the virus, according to Medscape Medical News.
In an interview, Li Tongzeng of Beijing Youan Hospital said, “Anal swabs appear to be more accurate at detecting the coronavirus than nasal or throat testing.”
“The virus lives longer in excrement or the anus than in the respiratory tract,” he added, “meaning anal testing might have fewer false negatives.”
Last year, a group of Chinese researchers published a study in Future Medicine, which found that some people tested positive for COVID-19 with anal swabs but were tested negative with nasal or throat swabs.
The researchers wrote, “We propose anal swabs as the potentially optimal specimen for SARS-CoV-2 detection for evaluation of hospital discharge of COVID-19 patients.”
However, not all scientists support the practice of using anal swabs for COVID-19 testing.
Yang Zhanqiu of Wuhan University told the Global Times that throat and nasal swabs are still the most efficient tests for COVID-19 because the virus is contracted through the respiratory system, not the gastrointestinal system.
“There have been cases concerning the coronavirus testing positive in a patient’s excrement, but no evidence has suggested it had been transmitted through one’s digestive system,” Zhanqiu said. The article was originally published in Medscape Medical News.
