COVID – 19 swabs 

COVID – 19 swabs are tools used for collecting samples to test for SARS – CoV – 2 infection.
II. Types of swabs
Nasal swabs
Method of collection:Medical staff will gently insert the swab into the nose of the person being tested, usually to a depth of 2 – 3 centimeters (which may vary slightly according to different sampling specifications). Then, they rotate the swab on the inner wall of the nasal cavity to obtain sufficient nasal secretion samples. This sampling method may cause some discomfort to the person being tested, such as a slight stinging sensation and a feeling of a foreign body, and some people may sneeze.

vantage：The virus content in the samples collected by nasal swabs is relatively high. Because after infecting the human body, SARS – CoV – 2 multiplies abundantly in the nasal and throat areas. Nasal swabs have high accuracy for early – infection detection.
Drawbacks:The sampling process may cause discomfort to the person being tested, especially for people with sensitive nasal cavities. Moreover, if the operation is improper, the nasal mucosa may be damaged.

2.Throat swabs

Collection Methods:Medical staff will use the swab to wipe the back wall of the throat and both sides of the tonsils of the person being tested. The person being tested needs to open their mouth and say “ah” to enable medical staff to collect samples smoothly. This process may trigger the nausea and vomiting reflexes of the person being tested.

vantage：Compared with nasal swabs, the sampling operation of throat swabs is relatively simple. It doesn’t require deep insertion into the nose, and the technical requirements for medical staff are slightly lower.

Drawbacks:Because the throat area is easily affected by food, saliva, etc., the virus content in the samples may be diluted, and in some cases, the accuracy of the test may be slightly lower than that of nasal swabs.

III. Material and structure of swabs

material：The heads of COVID – 19 swabs are usually made of synthetic fiber materials such as polyester and nylon. These materials have good water – absorption and release properties, can effectively adsorb and release samples, and have little impact on virus activity, and will not destroy the virus structure during sampling, affecting subsequent tests.

The shafts of the swabs are generally made of plastic materials, such as polypropylene. This material has a certain degree of flexibility, which is convenient for medical staff to operate, and also has good corrosion resistance and stability, and can remain intact during sampling, transportation, and testing.

composition：The heads of the swabs are flocculent or brush – like in shape. This structural design can increase the contact area with the samples, thereby improving the efficiency of sample collection. The shafts are usually elongated and of moderate length, which is convenient for handheld operation. Some swab shafts also have a breakpoint design. After sample collection, the head of the swab can be easily broken off and placed in the sample preservation solution to reduce the risk of sample contamination during transfer.

IV. The role of swabs in the testing process
1.Sample collection：Swabs are the first step in the entire COVID – 19 testing process. Accurate sample collection is the key to ensuring the reliability of test results. Whether it is nasal swabs or throat swabs, medical staff need to strictly follow the operating specifications for sampling to obtain sufficient and effective samples.

2.Sample preservation and transportation

After collecting the samples, the swabs are usually placed in a sampling tube containing a preservation solution. The role of the preservation solution is to maintain the activity of the virus and prevent the virus in the samples from becoming inactive or degrading during transportation and storage. The sampling tubes are generally sealed and transported to the laboratory for testing under specified temperature conditions (usually cold – storage).

V. Quality control and standards
Production quality control：Manufacturers of COVID – 19 swabs need to follow strict production standards. In terms of raw material procurement, it is necessary to ensure that the fiber materials and plastic shafts of the swabs meet biological safety and quality requirements. During the production process, strict tests need to be carried out on the size, shape, and water – absorption properties of the swabs. For example, the length and density of the flocculent on the head of the swab need to be within the specified range to ensure the effectiveness of sample collection.

International and national standards：There are relevant international medical device standards to regulate the production and quality of swabs. In China, there are also corresponding national standards and industry standards. These standards stipulate the performance parameters, biological safety, packaging, and labeling requirements of swabs. Swabs that meet the standards can be used for clinical testing to ensure the accuracy and reliability of test results.