Many areas require anal swab testing for some immigrants. Is the accuracy of anal swab detection high?

Since the outbreak of new crown pneumonia, virus detection has been the first line of defense against the epidemic. From the nasopharyngeal swab, oropharyngeal swab nucleic acid detection, lgM serum antibody detection, in order to improve the accuracy of detection, another hot search was conducted, that is, anal swab detection!

As the name implies, anal swab is to collect anal samples for virus detection. The reason why this detection method is proposed is because experts say that for some asymptomatic or mild infected people, the condition will recover quickly after infection, and pharyngeal nucleic acid may not be detected for 3 to 5 days.

It was found that the positive duration of nucleic acid in feces or anal swab of some infected people was longer than that in upper respiratory tract. Therefore, increasing the detection of anal swab nucleic acid can improve the detection rate of infected people and reduce missed diagnosis.

Simply put, the purpose of doing this is to improve the detection rate and reduce the probability of false negative. ?

Anal swab sampling is usually more accurate. The accuracy of anal swab sampling is because it is one of the very accurate detection methods to take samples from rectum to check whether there are pathogenic bacteria in the body. For example, in the case of COVID-19 epidemic, anal swab sampling can be combined with nasopharyngeal swab and oropharyngeal swab, which can improve the positive rate and reduce the missed diagnosis rate.

For COVID-19, some will stay in the respiratory tract, while others will easily stay in the digestive tract. Will be excreted with feces, so this part of the virus may stay on the intestinal wall, so it may be collected during anal swab sampling, so the relative detection rate and accuracy of anal swab sampling are high.

However, it should be emphasized that, considering that anal swab collection is not as convenient as throat swab, at present, only throat swab and anal swab are collected from key populations such as isolation points at the same time.

Rectal sample detection is considered to be more reliable and accurate than nasopharyngeal sample detection, but not everyone agrees. Because when doing anal swab test, you should soak 2-3 cm long cotton swab in salt solution, and then analyze the sample. Using this detection method has a greater chance to find traces of virus activity, because the virus stays in the rectum for a longer time than in the respiratory tract. Previously, 1000 primary school students and faculty members in Beijing had received such tests. ?