Although they are concerned about the transition to the COVID-19 test system, which adds the Antigen Rapid Test to the current PCR test, opinions are divided as they argue that this is only a concern. Unlike the initial virus that occurred in Wuhan two years ago, mutant viruses such as Omikron have a lot of detection in the body, so the Antigen Rapid Test can play a sufficient role, but they are still concerned.

According to the medical community on the 28th, concerns and expectations were simultaneously confirmed by the medical association over the government's transition to the COVID-19 test system. The COVID-19 test method includes PCR tests that amplify and test genes and Antigen Rapid tests that use the principle of antigen detection by immune responses after virus infection.

PCR (rRT-PCR, qRT-PCR), which collects secretions by inserting cotton swabs into the nostrils, has more than 98% accuracy and 100% specificity, and PCR through saliva reaches 92% sensitivity and 100% specificity. Although the accuracy is high, the results can be confirmed one to two days after the test, considering the time required for genetic testing and sample transfer.

On the other hand, the Antigen Rapid Test has a sensitivity of 90% or more and a specificity of 99%. The Antigen Rapid Test is used at a time when the amount of virus in the body is high to obtain more accurate results, and when used at a time when the amount of virus is low, false negative results are likely to be derived.

GCMS's Antigen Rapid Test "GENEDIA W COVID-19 Ag"

The sensitivity of 80% means that 80 out of 100 samples confirmed positive by genetic testing are tested positive, but 20 are incorrectly tested negative. However, the Antigen Rapid Test has the advantage of being able to determine whether or not to be infected immediately when rapid results are needed in the field.

The KSLM is concerned about the government's transition to the inspection system

Sung Heung-seop, director of infection control at The KSLM, said, "We have built up to 850,000 test capabilities a day with PCR, but it is difficult to understand why it was approved as a test method even though experts pointed out the low sensitivity of rapid antigen testing several times." He pointed out, "The fact that the accuracy of the rapid antigen test is more than 90% is the value when the virus emission is at its maximum level from 3 to 5 days after the onset of symptoms."

The argument that the test system needs to be changed is also convincing as antiviral drugs that are directly linked to the prognosis were introduced in the early stages of administration.

Unlike the early Wuhan virus, the late mutation that led to Delta and Omicron is characterized by strong propagation power due to the large amount of viruses. 99% of new confirmed patients in the U.S. are infected with Omicron, and more than 50% of them are currently infected with Omicron in Korea, and have already become the dominant species.

Kang Yoon-hee, a specialist in diagnostic testing, explained, "Before delta mutations, there were certainly not many detection of viruses in the body, but the situation changed rapidly due to mutations." Specialist Kang Yoon-hee explained, "The lower the Ct value, the higher the amount of virus emitted, the more sensitive the sample was 81%, and most of the ohmicron mutations were less than 23%."

Studies on the subject of changes in the sensitivity of antigen testing and relative accuracy with PCR are also accumulating.A comparative test of the Antigen Rapid Test and PCR conducted by researchers at Johns Hopkins Bloomberg School of Public Health (JHSPH) such as Andy Pekosz was released in November last year. The study compared the two test methods by collecting upper respiratory samples from 251 people 7 days after the outbreak of COVID-19.

As a result, the positive prediction value of the Antigen Rapid Test was 90%, higher than 70% of rt-PCR. Based on this, the researchers judged that "antigen testing can be a better factor for people with a high risk of having a highly contagious virus."