How to Swab For Covid Test
Since the outbreak of novel coronavirus pneumonia, we must have experienced nucleic acid testing. Covid swab test Nucleic acid detection plays a very important role in the process of infection diagnosis of COVID-19. It can not only find asymptomatic patients in the incubation period as much as possible but also greatly reduce the risk of infection.
Nucleic acid detection is so important. Next, Dr Li will take you to have an in-depth understanding of the relevant principles of nucleic acid detection, the difference between mixed collection and single collection of nucleic acid detection, and the matters needing attention in nucleic acid detection, to help you better protect yourself while popularizing knowledge.
To understand nucleic acid detection, we must understand the detection principle. Let’s take a look at its detection principle first.
What is the principle of nucleic acid detection?
Nucleic acid, the genetic factor of the virus, is a macromolecular chain composed of four nucleotides. Different molecules represent different nucleotides and form a long chain. Nucleic acid detection is through the detection of nucleic acid in the chain, and this segment of nucleic acid is COVID-19 specific, other viruses do not.
The substance detected by the nucleic acid is the nucleic acid of the virus. At present, the detection technology is mainly through PCR (polymerase chain reaction) technology to detect the nucleic acid of the virus. During the detection, the nucleic acid chain of COVID-19 was used as the detection target, and the target gene sequence was amplified by PCR Test, which was combined with a fluorescent labelled probe added in the test reagent to produce a fluorescence signal.
The three forms of nucleic acid detection have their advantages.
Nasal swab test
This test method is to insert the test swab vertically into the nostril. And gently rotate the swab, stay in the nasal cavity for about 15 seconds, to test.
Compared with throat swabs, nasal swab testing is more accurate for inexperienced testing personnel. And the risk of exposure is lower. However, it is not suitable for some patients with nasal allergies, high blood pressure and people who take anticoagulation and antiplatelet for a long time.
Throat swab test
At present, the most widely used detection method is also a form that is often used by everyone. During the sampling process, the patient opened his mouth and made an “ah” sound, and the testing personnel used a sterilized cotton swab to gently and quickly wipe the pharyngeal lateral wall and posterior pharyngeal wall of the subject many times.
Throat swab testing: Often used in the testing process because it is more convenient and fast to collect, and it is more acceptable to the public, but the risk of exposure is also greater.
Anal swab test
This test method is a method of inserting a test swab into the anus and taking a sample at the fold of the anus or taking a sample at 2 to 3 cm for a new coronavirus test.
Many patients reject anal swab testing, but anal swabs can improve the accuracy of testing for new coronavirus infections to a certain extent. Some patients indeed have negative throat swabs, but positive ones are detected by anal swabs. In some patients, the anal swab test was still positive after the other two tests turned negative.
Why do multiple nucleic acid tests need to be performed?
Multiple nucleic acid tests are necessary for epidemic prevention and control.
A negative nucleic acid test does not mean that the tested person is not at risk of infection. Any detection method has the possibility of errors, especially in high-risk areas. To ensure the accuracy of the inspection results and better prevent and control the spread of the epidemic, multiple rounds of inspections must be carried out. There are also the following reasons for taking multiple rounds of detection:
After virus infection, the human body has a certain value-added period. When testing, if the virus in the body does not reach a certain concentration, we may not detect the virus.
When the specimen was collected, due to the different sampling methods, no virus cells were collected. False-negative specimens can also lead to inaccurate collection results.
Errors in the transportation process and storage of samples for inspection will also affect the results of nucleic acid testing.
Therefore, for risk areas and special populations, multiple rounds of nucleic acid testing must be carried out to more accurately and effectively detect the virus source, so as to better and more accurately prevent and control and identify infected people, and cut off the source of the virus. No matter what kind of inspection process, attention must be paid.