New crown antigen testing is generally inaccurate beyond 30 minutes. It is usually observed within 15 minutes of the test, preferably no longer than 30 minutes. If it takes longer than 30 minutes, the test will be invalid. New Crown Antigen tests older than 30 minutes may have false positive results in the T-zone due to air contamination or inactivation of antigens such as labeled immunoproteins. False positive results in the T-zone may be due to airborne contamination or inactivation of antigens such as labeled immunoproteins. Failure of the NeoCrown antigen test beyond 30 minutes may also be due to the quality of the test strip itself, which is not clinically diagnostic beyond the prescribed reading time. The new crown antigen test has an observation period of validity, after this time the test results will be inaccurate, so it is necessary to quickly determine the results, when it is too late to observe the results can be photographed to leave the results.