How does an antigen detection kit work? What is the difference between it and nucleic acid testing?

Recently some people have started to use antigen detection kits for testing, so how should antigen detection kits be used? What is the difference between it and nucleic acid testing?

What is the difference between antigen testing and nucleic acid testing?

These two methods of detection work in the way of detection research objectives to carry out different. Antigen detection technology now most companies are using a protein structure called "N protein" as a target antigen, this binding protein is like the head, arms and legs of the new crown, nucleic acid testing development goal is to detect the nucleic acid wrapped in the virus, is the new crown virus specific genes.

The second is a different method of detection. Antigen testing can be done at home, nucleic acid testing requires equipment and is a more cumbersome process.

The advantages and disadvantages of the two tests are different.Rapid antigen nasal swab The advantages of antigen testing are:First, the test is fast, with results available in 15 to 20 minutes (according to the instructions); second, no special instrumentation is needed. As long as the test kit is available, residents can operate it at home or at a quarantine site and get the results. Nucleic acid testing, however, involves multiple processing steps and usually takes several hours to get the results.

The advantage of nucleic acid testing is that it is more reliable. Nucleic acid testing is like a paternity test. If the nucleic acid amplification test is positive, especially if it has been reviewed by the Centers for Disease Control and Prevention (CDC), then it is almost certain that an infection has occurred. Antigen testing is slightly less reliable. The specificity of antigen testing reagents that have been approved by the state is between 95-99%, meaning that if 100 antigen tests are positive, then about 95-99 people are infected, and the sensitivity of antigen testing is 75-98%, meaning that if 100 people are infected, then about 75-98 can be detected by antigen testing, so there is a certain amount of underdetection. That is to say, if 100 people are infected, then about 75-98 people can be detected by antigen detection, so there is a certain possibility of missed detection, so the current national diagnosis and treatment guidelines clearly stipulate that antigen detection can not be used as a basis for diagnosis.

What is the role of antigen detection in epidemic prevention and control?

The biggest advantage of antigen detection technology is the operation method is simple, fast results, it is in the epidemic prevention and control to solve the main research problem, is to improve the "early detection" ability. Prevention and control of infectious diseases, early detection is the core content elements, only students as soon as possible to find infected people, in order to control the spread of information in a smaller range, conducive to the prevention and control of social epidemics; from the perspective of the development of personal mental health, "early detection" is also conducive to the early rescue and treatment of patients as soon as possible, so that patients can give priority to access to basic health care resources. From the perspective of personal mental health development, "early detection" is also conducive to early treatment, so that patients can receive basic medical services as soon as possible. This is why the new national guidelines include antigen testing as an important complement to nucleic acid testing.

What are the three steps of antigen self-testing?

Step 1: Preparation for self-testing

Wash your hands. Before opening the package, wash your hands with running water or hand sanitizer. This will minimize errors due to contamination.

Carefully read the package instructions and considerations related to antigen self-testing to understand the testing process, which may vary slightly from manufacturer to manufacturer in terms of details.

Reagent Preparation. Check that the antigen self-test reagents are within shelf life and that the contents are not missing or damaged. Place the antigen test card in a flat, clean area after unpacking.

Step 2, specimen collection

Blow your nose with toilet paper before collecting the specimen. For age 14 years and above, you can design your own protective nasal swab sampling. for children aged 2-14 years, other student adults will do the sampling on your behalf. Special emphasis should be placed on sampling a link, sampling different parts of the right or wrong, deep enough, as well as the degree of accurate understanding of the enterprise, the strength of the results of the analysis of the study will have a greater impact on the development. Therefore, the sampling should be done in accordance with the operating procedures.

The third step, antigen detection

Finally, the results will be judged. Waiting for the results must be patient, according to the reagent specifications waiting time (usually 15 to 20 minutes), the results show more credible.

Invalid result: No red or purple streak is shown at "c", regardless of whether the streak is shown at "t" or not. The result is invalid and needs to be retested with a new test strip.

Negative result: Red or purple stripe at "C" but not at "T".

Positive result: Both "C" and "T" show red or purple stripes, and the color of the strip at "T" can be darker or lighter, both are positive results.