Does a positive antigen test mean infection? What other questions do you have about antigen testing? Experts explain →

Can antigen testing and nucleic acid testing replace each other? Does a positive self-test for antigen mean that you are infected with the new coronavirus? Recently, antigen testing has once again attracted public attention. In this regard, Li Dongzeng, chief physician of the Department of Respiratory and Infectious Diseases of Beijing You'an Hospital, answered them one by one in an interview with a reporter from the People's Daily Health Client on December 4.

01

Can antigen testing and nucleic acid testing replace each other?

cannot

Li Dongzeng introduced that although nucleic acid testing and antigen testing are both direct methods of detecting viruses, the former relies on "grabbing" the genetic material inside the virus to obtain results, while the latter relies on identifying the "outer coat" of the virus - the N protein, to indirectly reflect whether the person is infected with the new coronavirus. The two testing methods have their own advantages and cannot replace each other .

"Antigen testing is very convenient and can be performed by everyone. The results can be obtained in 15 minutes, so it is very suitable for rapid screening." Li Dongzeng pointed out, "Especially when COVID-19-related symptoms appear, antigen testing can immediately give you a preliminary judgment of yourself."

In contrast, since nucleic acid test specimens must be tested in the laboratory, the process is cumbersome, so it usually takes 4-6 hours to get the results. In addition, without "mixed sampling" to lower costs, nucleic acid testing still has a clear price disadvantage.

02

Does a positive self-test antigen mean that you are infected with the new coronavirus?

uncertain

Li Dongzeng told reporters that according to the current diagnosis and treatment plan, nucleic acid testing is the "gold standard" for diagnosing COVID-19 due to its higher accuracy, which is also irreplaceable by antigen testing at present. "Therefore, even if the antigen test is positive, it needs to be confirmed by nucleic acid testing. In other words, if a person is antigen positive but the nucleic acid test is negative, he or she cannot be diagnosed with COVID-19 at present."

When encountering the above situation, Li Dongzeng pointed out that a positive antigen means that the possibility of infection is relatively high, and it should be reported to the community or unit in a timely manner, especially for those with fever and respiratory symptoms, who need to report as soon as possible.

03

Do ordinary families need to stockpile antigen testing reagents?

Proper reserves

Regarding whether antigen testing will play a greater role in epidemic prevention in the future , Li Dongzeng said: " I think it will be like this, and this is also what is being done abroad now. "

"When there are symptoms, the accuracy of antigen testing is still relatively high. When it is inconvenient to do nucleic acid testing, and you feel unwell and have symptoms such as fever, dry cough, sore throat, etc., you can do an antigen test first. If problems are found, you can take timely protection to avoid infecting people around you." Li Dongzeng said.

Do ordinary families need to stock up on some antigen test kits? Li Dongzeng suggested: "You can stock up appropriately and be aware of the situation." Winter is the season when respiratory diseases are most prevalent. In addition, the current national epidemic situation is also quite severe. In areas where the new coronavirus outbreak occurs, it is recommended to stock up on some antigen test kits at home.

Source: People's Daily Health Client Comprehensive Health Times, Beijing Release

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