Antigen self-test generally refers to the new coronavirus antigen test, the antigen test result has dark and light indicating that the antigen test result is weakly positive. Antigen test strips can be divided into two zones, a C zone, which is the quality control line, and a T zone, which is the detection line. Whether the test result is positive or negative, a red or purple line will appear in the C zone. After the antigen test paper is tested, if the C area appears to be colorful and the T area also appears to be colorful, it means that the test paper is working properly. If the red bar in the C area is darker and the red bar in the T area is lighter, this would be a weak positive result, and if the red bar in the C area is darker and the red bar in the T area is darker, it means that the result is a strong positive. A weak positive result could be a low viral load or a false positive result. It needs to be retested or reviewed with a nucleic acid test.