In nucleic acid testing, what are the main types of specimens collected, and what are the advantages and disadvantages of each?
A variety of specimens can be collected for laboratory testing at the time of diagnosis of COVID-19 cases. Upper respiratory tract samples can be collected: including nasopharyngeal swabs, oropharyngeal swabs, etc.; lower respiratory tract samples can also be collected: deep cough sputum, bronchoalveolar lavage fluid, bronchial lavage fluid, respiratory tract aspirates, etc.; stool samples can also be collected / Anal swabs, blood samples, serum samples, urine samples, etc.
Currently, the commonly used specimen types for nucleic acid testing are nasopharyngeal swabs, oropharyngeal swabs and sputum, each of which has its own advantages and disadvantages. The pharynx, deep inside the nose and mouth, is divided into three parts: the nasopharynx, the oropharynx, and the laryngopharynx.
Nasopharyngeal swab collection is to insert a sampling tool into the nasal cavity to collect nasopharyngeal specimens. The detection rate and accuracy rate will be higher, but the operation is more complicated and difficult. Some people are not easy to adapt to, and people’s acceptance is slightly lower.
Oropharyngeal swab collection is to collect oropharyngeal specimens through the mouth. The sampler can see the pharynx to be sampled, but the sampling is more irritating to the oropharyngeal mucosa, which may cause the sampled to cough, nausea, or even vomiting. Wait for the reaction.
Collecting sputum samples, especially deep cough sputum samples, can also detect the nucleic acid of the COVID-19, and the positive detection rate is relatively high, but deep cough sputum samples are not saliva samples, and if no qualified deep cough sputum samples are collected, it may appear False negative results.
Compared with nasopharyngeal swabs and sputum specimens, oropharyngeal swabs are quick to collect, simple and easy to implement, and the detection rate can meet the requirements. Usually, for low-risk groups, throat swabs can be collected for testing. For some high-risk groups, such as asymptomatic infected persons, entry personnel, close contacts and other high-risk groups, in order to collect specimens with higher viral load and increase the positive detection rate, nasopharyngeal samples should be collected during isolation and observation. Swabs for nucleic acid testing.
During nucleic acid screening of large-scale populations, the collection of throat swab specimens is highly efficient, easy for people to accept, and easy to organize and carry out. Suspicious positive persons can be screened out quickly, and isolation and control measures can be quickly taken, which is conducive to the rapid treatment and prevention of clustered epidemics. Effective control.