What if a 'False Negative' Appears Despite Actual Infection... Low Accuracy Rapid Antigen Tests Raise Concerns Over Worsening Spread

'Rapid Antigen Test' Introduced Nationwide from Today (3rd)
Health Authorities: "Low Probability of Positive Cases Testing Negative"

On the 30th of last month, when the number of new COVID-19 cases reached a record high for the sixth consecutive day at 17,532, citizens visiting the COVID-19 screening clinic at the Jongno-gu Public Health Center in Seoul conducted rapid antigen tests using self-test kits. If the test result is positive, they immediately move to the adjacent PCR testing site for a PCR test. Photo by Kim Hyun-min kimhyun81@

[Asia Economy Reporter Yoon Seul-gi] Rapid antigen tests were introduced nationwide from the 3rd to respond to the spread of the COVID-19 Omicron variant, but controversy continues due to their lower accuracy compared to polymerase chain reaction (PCR) tests. Concerns are growing that the rapid antigen tests could negatively impact the spread of COVID-19, as it has been confirmed that 'false positives' account for 24%, with cases where individuals tested positive on rapid antigen tests but negative on PCR tests.

According to the Central Disaster and Safety Countermeasure Headquarters on the 3rd, among 84,000 rapid antigen tests conducted from the 26th to the 31st of last month at 41 screening clinics in four regions including Gwangju, Jeonnam, and Pyeongtaek and Anseong in Gyeonggi Province, 687 cases (0.8%) were confirmed positive. The rapid antigen test is conducted using self-test kits to respond to the spread of the highly transmissible Omicron variant. Results can be confirmed within a maximum of 30 minutes, enabling rapid testing.

After a positive rapid antigen test, a linked PCR test must also be positive for a final confirmed diagnosis. Among the PCR tests conducted following positive rapid antigen tests, 523 cases were positive. The remaining 23.9% (164 cases) tested positive on the rapid antigen test but were ultimately negative on the PCR test. Approximately one in four people who tested positive on the rapid antigen test were actually not infected, representing 'false positives.'

At the screening clinic of Anseong City Public Health Center in Gyeonggi Province, where the Omicron quarantine system began, an official is preparing a rapid antigen test negative confirmation on the morning of the 26th.
[Image source=Yonhap News]

Given this situation, concerns about rapid antigen tests are increasing. Their accuracy is lower than PCR tests, so there is a possibility of false negatives even in actual confirmed cases. If a false negative occurs, individuals may not undergo additional testing and continue daily activities, increasing the risk of further infection spread.

The government explained that when a rapid antigen test result is negative, it is considered negative despite some possibility of false negatives because the accuracy is relatively high. Son Young-rae, head of the Social Strategy Division at the Central Accident Response Headquarters, said, "Due to the nature of rapid antigen tests, accuracy is lower when the result is positive, so it is confirmed again with a PCR test afterward. When the result is negative, it shows a considerable level of accuracy," adding, "The probability of a positive case testing negative is low."

However, Son added, "For the general population who are not priority test subjects, there is a possibility that the confirmation rate may decrease somewhat during the PCR diagnostic process following the rapid antigen test due to reduced accuracy."

Park Young-jun, head of the Epidemiological Investigation Team at the Central Disease Control Headquarters, explained, "When a rapid antigen test is positive, the probability that this result is truly positive is about 76.1%. However, when the result is negative, it is necessary to confirm with a PCR test whether it is truly negative, but realistically it is difficult to conduct this, so it is hard to know the specificity (negative predictive value)."

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