A very light line on the T of the new crown antigen test may be caused by a wrong test procedure, a weak positive result, a false positive result, and so on. 1. Incorrect testing procedure: The new crown antigen test requires the sample swab to be rotated several times in the nasal cavity, then left for 30 seconds, and then pressed on the swab head across the sampling tube for more than 5 seconds after removal, so as to elute the sample. If the test procedure is not correct, it is possible to have a very shallow line at the T position of the antigen test. 2. Weakly positive result: If the antigen test has two bars, with a clear line at the C position and a very light line at the T position, this may indicate a weakly positive result. 3. False-positive results: When doing antigen testing, if you are interfered by your own and environmental factors, there may also be a very shallow line at the T position of the antigen test, resulting in a gap in the test results and thus a false-positive result. When performing the new crown antigen test, it is necessary to standardize the operation according to the instructions in order to ensure the accuracy of the experimental results, and if any abnormality occurs, it is necessary to consult the doctor in time, improve the nucleic acid test, and treat reasonably under the guidance of the physician.