The change to two bars in the new crown antigen assay over 30 minutes may be due to an increase in nonspecific binding as the reaction time increases. For the New Crown Antigen test, the reading time is usually 15-30 minutes after the sample is added to the droplet (varies by kit manufacturer and is based on the instruction manual), and the results are accurate if read within the reading time provided in the instruction manual, and results below or above the reading time are usually considered inaccurate. When the self-test for neocoronavirus antigen takes more than 30 minutes, the optimal time allowed for the reading is usually exceeded. At this time, two bars may appear due to the binding of non-specific proteins (not neocoronavirus surface proteins) to the antibodies on the test paper, which is not an accurate result.