"Do I Not Need a PCR Test?"... Self-Test Kits Cause Anxiety Even When Results Are 'Negative'

109,831 New Cases on the 18th... Weekly 'Doubling' Continues
Citizens Anxious Amid Surge of False Negatives in Self-Test Kits

COVID-19 Self-Test Kit. [Image source=Yonhap News]

[Asia Economy Reporter Heo Midam] As the number of new COVID-19 cases continues to hit record highs daily, controversy persists over the accuracy of self-test kits (rapid antigen tests). This is because there have been numerous cases where the results of self-test kits and polymerase chain reaction (PCR) tests differ. For example, a 'negative' result on a self-test kit but a 'positive' result on a PCR test.

Given this situation, many are concerned that the number of confirmed cases could increase further due to false negatives (false negative reactions) from self-test kits. Some are calling for lowering the threshold for PCR testing.

On the 18th, the number of new COVID-19 cases exceeded 100,000 for the first time. According to the Korea Disease Control and Prevention Agency (KDCA) Central Disease Control Headquarters (CDCH) tally, the number of new confirmed cases as of midnight that day was 109,831.

The number of new confirmed cases, which was 18,337 on the 1st, rose to the 20,000s from the 2nd, 30,000s from the 5th, 40,000s from the 9th, 50,000s from the 10th, 90,000s on the 16th, and surged to 100,000s on the 18th. In particular, the 'doubling' phenomenon, where cases double every week, continues.

On the 18th, when the number of new COVID-19 cases exceeded 100,000 for the first time in history, citizens lined up to get tested at the screening clinic of Songpa-gu Public Health Center in Seoul. Photo by Mun Ho-nam munonam@

Earlier, the government decided it could no longer maintain the existing PCR testing system due to the surge in cases caused by the Omicron variant and switched the quarantine system on the 3rd. The strategy is to focus resources on managing high-risk groups. As a result, PCR tests are currently only available for ▲elderly aged 60 and above ▲those requested for close contact testing by public health centers ▲those with medical opinions ▲workers in infection-vulnerable facilities ▲and those who test positive on rapid antigen tests or emergency screening tests.

Others must first use self-test kits at screening clinics or receive professional rapid antigen tests at local respiratory clinics. Only if the result is 'positive' can they receive a PCR test. Self-test kits and professional rapid antigen test kits are essentially the same product. The difference lies in whether the test is self-administered or conducted by a professional, with the latter being considered more accurate. Professionals collect specimens by inserting the swab deep inside the nasal cavity.

However, it has been found that many people remain anxious despite multiple 'negative' results from self-test kits. This is because cases where self-test kit results and PCR test results differ have been occurring repeatedly.

Musical actor Kim Junsu took a total of five rapid antigen tests, all of which were negative, but was finally confirmed positive through an additional PCR test. Kim Junsu had completed a Moderna vaccine booster shot. Broadcaster Jeon Hyunmoo also tested negative three times consecutively on rapid antigen tests but tested positive on the fourth test. He was later confirmed positive through a PCR test.

Given this situation, many question the accuracy of self-test kits. A job seeker in their mid-20s, who recently tested positive for COVID-19, said, "I had a sore throat and felt weak, so I used a self-test kit three times, all negative. But since the Omicron symptoms were similar to mine, I took the self-test kit once more just in case, and it came out positive." They added, "The PCR test result was also positive."

They continued, "It seems the accuracy is significantly low. Many people might unknowingly go around even if they are infected. It only causes confusion," they criticized.

On the 18th, when the number of new COVID-19 cases exceeded 100,000 for the first time in history, citizens are taking rapid antigen tests at the testing center of Songpa-gu Public Health Center in Seoul. Photo by Moon Honam munonam@

Self-test kits detect the presence of the virus using specimens collected from the nose, allowing results to be confirmed within 30 minutes. However, if the viral load is low, there is a high possibility of errors such as diagnosing a positive case as negative. On the other hand, PCR tests require a gene amplification process and take about six hours but have the advantage of detecting even very small amounts of the virus.

Previously, the Korean Society for Laboratory Medicine also pointed out that the sensitivity of rapid antigen tests is below 50% even when performed by medical personnel and below 20% when self-administered. This means that out of 10 infected individuals, only 5 test positive when tested by medical personnel, and only 2 test positive when self-tested. Sensitivity refers to the probability of correctly identifying COVID-19 patients as positive.

Some suggest lowering the threshold for PCR testing or replacing the less accurate rapid antigen tests with 'rapid PCR tests.'

Rapid PCR tests analyze specimens immediately on-site after collection and can confirm positivity within about an hour. However, the number of tests that can be processed at once is limited, making it difficult to apply in large-scale outbreaks. Currently, they are only used in emergency rooms where patients need urgent surgery or in some local governments.

The quarantine authorities also maintain that rapid PCR tests cannot currently replace rapid antigen tests. On the 15th, Son Youngrae, head of the Social Strategy Division at the Central Disaster and Safety Countermeasures Headquarters, responded to a question at a COVID-19 regular briefing about whether rapid antigen tests could be replaced with rapid PCR tests, saying, "Rapid PCR tests are used in emergency rooms, but there are significant limitations in increasing their quantity, so expansion is not easy."

This content was produced with the assistance of AI translation services.