How to collect anal swab for nucleic acid detection?

In order to ensure the accuracy of nucleic acid detection, anal swabs have been recently added to throat swabs and nose swabs for nucleic acid detection. Many citizens are very concerned about this. What is the significance of anal swab test? Why do you want to add anal swab and how to detect it? Let's get to know each other.

Why increase anal swab? Convenient and quick, suitable for large-scale screening, and the positive duration of anal swab nucleic acid is longer.

Dong Li, deputy chief physician of the Department of Respiratory and Infectious Diseases of Beijing You 'an Hospital, said in an interview that oropharyngeal swabs are mainly used for nucleic acid detection in the screening of people related to the COVID-19 epidemic, because they are convenient and quick, and are suitable for large-scale screening. The accuracy of nasopharyngeal swab in detecting COVID-19 nucleic acid is higher than that of oropharyngeal swab, but it makes people feel uncomfortable.

For some asymptomatic or mild infected people, the condition recovers quickly after infection, and pharyngeal nucleic acid may not be detected for 3 ~ 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.

At present, anal swab collection is only for key populations, and serum antibodies can be added when necessary.

Dong Li once said that considering that the collection of anal swabs is not as convenient as that of throat swabs, at present, only throat swabs and anal swabs are collected from key populations such as isolation points. The serum antibody of COVID-19 infected people lasts for a long time, most of which can last for more than half a year. When necessary, carry out serum antibody detection for key populations. The purpose of this is also to improve the detection rate and reduce the probability of false negative.

There are several ways to detect nucleic acid: throat swab detection, oropharyngeal swab sampling and nasopharyngeal swab sampling. And serum antibody testing.

Oral and pharyngeal swab sampling is to smear the throat with a cotton swab and take the epithelial cells of the throat for detection. The detection method is generally that the examinee opens his mouth to make an "ah-"sound, and the inspector takes samples with a cotton swab. There is no risk of trauma during the test, so it is a very safe test.

And nasopharyngeal swab collection. Generally, a fine cotton swab is inserted into the nostril, reaching the posterior wall of nasopharynx from the inferior nasal passage, and then the cotton swab is twisted to take samples. Generally, you are likely to feel vomiting and need to wait patiently.

Now there is another anal swab sampling method.

Anal swab detection The so-called anal swab detection is to insert a sampling cotton swab into the anus for 2 to 3 cm, or wipe the sample at the folds around the anus. Anal swab tests have been used to screen for parasitic infections. If you eat unsanitary food at ordinary times, the parasites in the intestine will lay eggs and be excreted with the stool. At this time, it is possible to find parasites through stool examination or anal swab.

Source: CCTV News, Xi Ankepu