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When the medical system tailored to Omicron is expanded nationwide, many people will first check for infection with a rapid antigen test instead of a diagnostic test. However, if we test positive there, we have to undergo a diagnostic test again. In the United States and the United Kingdom, based on the results of the rapid antigen test, we immediately classify them as confirmed cases.



Cho Dong-chan, a medical reporter, examined which method is better.



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Since the rapid antigen test is not accurate, it is the policy of our quarantine authorities to confirm it with a more accurate PCR test if it is positive.



However, in 20 countries around the world, including the United States, the United Kingdom, and Australia, if the rapid antigen test is positive, treatment begins immediately.



When the number of confirmed cases increases, PCR testing alone cannot handle it.



If there are 10,000 confirmed cases per day, 500,000 actual tests are performed, and if the number of confirmed cases is 30,000, 1.5 million tests are performed.



Domestic PCR tests are limited to 850,000 per day.



If more than 30,000 cases occur per day, PCR testing is delayed and medication is delayed.



If you look at the red line, the amount of virus in Omicron starts to increase on the 3rd day of infection, and decreases on the 8th day.



Let's do a PCR test. The line below is the positive test standard, and it catches a relatively small amount well.



On the other hand, the rapid antigen test is an upper level test, but it is positive when the amount of virus is high to a certain extent.



So, if the rapid antigen test is positive, the PCR will also be positive.



A recent Canadian study found this probability to be 99.95%.



If the US, Canada, and UK test positive for rapid antigen, the drug is administered immediately without PCR test.



But let's look at A and B.



At this time, PCR is positive, but rapid antigen test is negative.



If you have been in contact with someone or have symptoms, it will be a false negative.



In this case, it is necessary to repeat the test after a day or two or PCR test to be positive.



So, if you look at the US guidelines, if the rapid antigen test is positive, you are infected, but if you are negative, it is not necessarily an infection.



Professor Oh Myeong-don of the Central Clinical Committee for Emerging Infectious Diseases emphasizes that rapid antigen testing can be more useful to effectively use a treatment drug that must be administered within 5 days of symptom onset.



False negatives can be supplemented with repeated tests, auscultation by a doctor, or X-rays.



(Video coverage: Hwang In-seok, video editing: Kim Byeong-jik, CG: Ryu Sang-soo, Kang Ryu-ra, Shim Su-hyeon)