Since the outbreak of New Coronavirus, we have initiated nucleic acid testing on a wide scale in order to screen out positive patients as soon as possible.

There are two main types of testing methods regarding New Coronavirus: one is antibody testing and the other is nucleic acid testing. The antibody test is mainly done by blood sampling, and the nucleic acid test relies on swabs, such as pharyngeal, nasal and anal swabs. The antibody test aims to observe whether the antibody titer in the patient's body is increased, but this is not significant for early testing; the nucleic acid test mostly uses pharyngeal swabs, which have relatively high specificity and sensitivity.

3 types of swabs, each with its own characteristics

1. Pharyngeal swab: The patient rinses his mouth with water and then opens his mouth to make the "ah" sound, using a tongue depressor if necessary. The doctor uses a sterilized cotton swab to gently and quickly wipe the lateral and posterior pharyngeal walls of the subject several times, which is currently the most commonly used method in clinical practice.

2. Nasal swab: The swab is inserted into the nostril in a vertical nose (face) direction during sampling until the finger is close to the nose, so that the swab stays in the nose for 15-30 seconds, and then gently rotated 3 times.

3. Anal swab: take a specimen by inserting a sampling swab 2 to 3 cm into the anus, or by wiping the sample in the folds around the anus.

The anal swab test is a new crown test recently incorporated, which was previously used mainly to screen for parasitic infections. If the usual diet is not hygienic, parasites in the intestine will lay eggs and be excreted in the stool, at which point the parasites may be detected using an anal swab.

It is worth mentioning that a few patients discharged from the hospital have reported exceptional cases of 2 negative pharyngeal swabs for nucleic acid but positive anal swabs, suggesting that the addition of anal swab testing can improve the detection rate of NICs to some extent.

For anal swabs, many people wonder under what circumstances to use? In this regard, the relevant infection specialists said that there is a possibility of fecal-oral transmission of New Coronavirus pneumonia. For example, those patients with intestinal symptoms as the main manifestation can appear at the same time anal swab, pharyngeal swab nucleic acid positive; and a small number of cases in the late course of the disease, pharyngeal swab, nasal swab nucleic acid are turned negative, the anal swab test is still positive. It is still necessary to add an anal swab.

Nucleic acid testing requires the full cooperation of the subject

1. 2 hours before the nucleic acid sampling try to avoid eating, half an hour, no smoking, drinking, chewing gum; the weather is hot, the queue is relatively long, make personal sunscreen preparation;

2. The sampling process will be irritating dry cough, nausea, vomiting and other symptoms, testers try to relax, deep breathing;

3. Remove the mask only when sampling, and put it on immediately after sampling;

4. Due to individual differences, tolerance, past medical history, there are rare complications and adverse consequences such as bleeding, infection, cardiovascular and cerebrovascular accidents;

5. If you have suffered from blood diseases, throat diseases, anticoagulants and other related risk factors, you need to inform the medical staff before sampling;

6. Leave the collection site immediately after collection and avoid spitting and vomiting around the collection site;

7. Due to the tight protection of medical personnel, it may not be able to hear the speech, it is recommended that the public write personal information such as cell phone number, home address, name and ID number on a small slip of paper in advance to save time and improve the efficiency of the test.