Rapid antigen testing is generally referred to as neocoronavirus antigen testing and may have a purple line if the test result is positive or negative. If the test result is invalid, no purple line will appear. After a tester takes the Neocoronavirus antigen test, a purple line or a red line will appear in the C and T areas on top of the test card if the Neocoronavirus antigen test result is positive. If the test result is negative for Neocoronavirus antigen, a red or purple line will appear in the C-zone and no color will be shown in the T-zone on the top of the test card. If the Neocoronavirus antigen test result is invalid, no purple or red line will appear in the C section on the top of the test card, and the T section will not show any color, regardless of whether a color bar appears or not, indicating that the result is invalid. It is recommended that if a purple or red line appears in the C or T zone after the new coronavirus antigen test, the patient needs to consult a doctor for nucleic acid testing in a timely manner, and isolation treatment is also required.