During the outbreak of the new coronavirus pneumonia, while everyone is doing personal protection, they are also very concerned about the epidemic situation.
Originally, the social season in winter and spring was a period of the high incidence of common colds and flu, and the most important means to control the epidemic was to screen out the real patients with new coronary pneumonia from many respiratory patients.
The following small series will introduce some common virus sampling detection methods for you.
Nasopharyngeal swab
Collect nasopharyngeal swab specimens within 3 days of the onset of the patient as much as possible.
Measure the distance from the tip of the nose to the earlobe with a swab and mark it with your finger, insert the swab into the nasal cavity in the direction perpendicular to the nose (face), and the swab should be at least half the length from the earlobe to the tip of the nose so that the swab stays in the nose for 15 ~30 s.
Gently rotate 3 to 5 times, quickly put the swab into a sample collection tube containing 2 ml of lysis buffer (the same as the lysis buffer in the nucleic acid extraction kit) or a cell preservation solution containing RNase inhibitors, and insert the swab.
Then break the sterile swab rod near the top, screw the cap tightly and seal it with parafilm.
Oropharyngeal swab
Collect throat swab specimens from patients within 3 days of onset as much as possible. It is advisable to use a sterile flocked swab for sampling, wiping the posterior pharyngeal wall with moderate force, avoiding touching the tongue; quickly put the sterile swab into the collection tube used for collecting nasopharyngeal swabs, and break it near the top Sterile swab rod, screw cap tightly and seal with parafilm.
Anal swab (feces)
For patients with gastrointestinal symptoms such as diarrhea in the early stage of the disease, an anal swab should collect a stool sample (soybean size) of 3-5g.
The specimens were collected in a screw-cap specimen collection tube containing 2 ml of normal saline (RNase inhibitor can be added if available) and sealed with parafilm.
How to collect nasopharyngeal swabs
There is absolutely no need for the sampler to stand directly opposite the patient. Regardless of whether the patient is sitting or lying, right-handed patients can stand on the right side of the patient, and left-handed patients can stand on the left side for sampling operations.
The advantage of standing on the side is that if the patient has a cough, sneeze, etc., it can be avoided in time.
After the nasopharyngeal swab is passed through the nostrils.
It is perpendicular to the coronal plane of the head or the face and penetrates deep from the inferior meatus to the posterior wall of the nasopharynx, and it is enough to feel the wall.
The nasopharyngeal swab enters the nasal cavity to a depth of approximately the distance from the tip of the nose to the earlobe (see figure).
The “American Society for Microbiology Clinical Microbiological Specimen Submission Guidelines. ” We ask to twist the nasopharyngeal swab on the nasopharyngeal mucosa, hold it for 10-15 seconds, and then take out. Children’s cooperation is poor.
We generally take out the Flocked swab in three to five seconds after fully twisting it 2-3 times.
Except for paying attention to the depth of the swab. We should also note that there is always the habit of having the patient lift their head completely, bend the swab, and take a sample. This is wrong.
In fact, the above approach is wrong. This operation will cause the swab head to stay in an incorrect position. And the final sample obtained is not a standard nasopharyngeal swab specimen.
