According to sampling methods, nucleic acid detection in novel coronavirus can be roughly divided into upper respiratory tract samples and lower respiratory tract samples. The upper respiratory tract samples are mainly nasopharyngeal swab and nasopharyngeal extract, while the lower respiratory tract samples are mainly bronchoalveolar lavage fluid and deep sputum. The specific detection method is as follows:

1. Nasopharyngeal swab: Swallow swab is to wipe both sides of pharynx, tonsils and posterior pharyngeal wall at the same time to obtain upper respiratory tract samples, and nasal swab is taken from nasal passage and nasal palate;

2. Deep sputum: ask the patient to cough deeply, collect the expectorated sputum and test it;

3. Nasopharyngeal extraction: insert the head of the collector connected with the negative pressure pump into the nasal cavity or trachea, and extract the mucus sample after turning on the negative pressure;

4. Bronchoalveolar lavage fluid: fiberoptic bronchoscopy is needed, which is a complicated operation.

At present, the commonly used screening method for nucleic acid detection is nasopharyngeal swab.

Before detection

Try to avoid eating 2 hours before nucleic acid detection to avoid vomiting; Do not drink (including drinking water), smoke, drink or chew gum 30 minutes before sampling; During clinical examination, it is necessary to reduce swallowing movements and not clear your throat (such as expectoration and spitting). Before collecting nasopharyngeal swab, the examinee should inform the collector whether there is any relevant past medical history or related matters. For example, the history of nasal surgery, curved nasal septum, blood diseases, throat diseases, or taking anticoagulants and other related risk factors; Testers need to wear masks correctly, take them off before testing, put them on immediately after testing, and prepare spare masks after pollution for easy replacement at any time.

undergo inspection

When collecting oropharyngeal swabs, the examinee leans back and opens his mouth to make an "ah" sound, which helps to expose his throat, but there will be symptoms such as irritating dry cough, nausea and vomiting in the process, and the examinee can cooperate with the collector to relax and take a deep breath as much as possible; There may be an itchy nose during the collection process, which stimulates sneezing. You can immediately cover it with paper towels (prepared in advance) or elbows.

After the test

Leave the collection site immediately after collection to avoid spitting and vomiting around the collection site. Pay attention to hand hygiene before and after nucleic acid detection, and wipe your hands with hands-free disinfectant or alcohol.