1. Oropharyngeal sampling: first press the tongue with a tongue depressor, then extend the head of the sampling swab into the throat, wipe bilateral pharyngeal tonsils and posterior pharyngeal wall, gently wipe the posterior pharyngeal wall, and avoid touching the tongue.

2. Nasopharynx sampling: use a swab to measure the distance from the tip of the nose to the earlobe and mark it with your fingers. Insert the sampling swab into the nasal cavity in the direction perpendicular to the nose (face). The swab should reach at least half the length from the earlobe to the tip of the nose. Keep the swab in the nose for 15-30 seconds, rotate it gently for 3-5 times, and take out the swab.

It is not difficult to see from the use method that whether it is oropharyngeal swab or nasopharyngeal swab, sampling is a technical activity, which is difficult and easy to pollute. The quality of the collected samples is directly related to the subsequent detection. If the virus load of the collected samples is low, it is easy to cause false negative and difficult to diagnose.

At present, the recommended samples for the kits sold on the market are mostly oropharyngeal swabs or nasopharyngeal swabs and alveolar lavage fluid. If venous blood samples, especially special nucleic acid detection tubes, are used to collect blood and extract purified RNA for detection, it can greatly reduce the work difficulty of sampling personnel. After all, the difficulty of collecting venous blood samples is not high, and like the detection of hepatitis C RNA, about 5ml EDTA anticoagulated blood samples are separated from plasma, and the extracted and purified RNA can fully meet the needs of PCR detection.