"Why Are Self-Test Kit Results Different Between Nasal (Negative) and Throat (Positive) Samples?"

At a domestic screening clinic, citizens are showing positive reactions on self-test kits.
[Image source=Yonhap News]

[Asia Economy Reporter Hwang Sumi] "The self-test kit showed a negative result, but when I swabbed my throat, it immediately showed positive."

Recently, claims have been circulating online that COVID-19 self-test kits yield more accurate results when used on the throat rather than the nose. Users have shared experiences where samples taken from the nose showed negative results, but samples from the throat tested positive.

According to the Korea Policy Broadcasting Corporation (KTV) on the 11th, experts dismissed this as a phenomenon caused by the varying locations of COVID-19 symptom onset at different times.

The coronavirus typically begins replicating in the oropharynx, where the uvula is located, then moves to the nasopharynx and spreads into the nasal cavity. Therefore, experts say that in the early stages of infection, the virus load is higher in the throat, making positive results more likely there, while later on, positive results are more likely in the nose. The difference in results depends on when the test is taken, and it cannot be concluded that throat samples are more accurate.

Experts actually state that nasal samples have higher accuracy because the amount of virus present in the nose during COVID-19 infection is greater. For this reason, even in polymerase chain reaction (PCR) testing, swabs are inserted into the nasal cavity to collect samples from the nasopharynx.

Additionally, experts warn that using self-test kits, which are approved by the Ministry of Food and Drug Safety for nasal use, on the throat can be quite dangerous.

Just as inserting a finger into the throat can trigger gagging, inserting a swab into the throat can cause a gag reflex, which may lead to the swab breaking and entering the lungs. This can cause aspiration pneumonia due to the intrusion of foreign substances other than pathogens. Moreover, there is a high risk of scratching or injuring the inside of the throat during the test.

In this regard, the Korea Disease Control and Prevention Agency recommends using products approved by the Ministry of Food and Drug Safety and following the conditions specified in the product approval.

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