Antigen tests that detect the protein structures of SARS-CoV-2 work on a similar principle to pregnancy tests. To do this, a sample of a nasopharynx swab is applied to a test strip. If the SARS-CoV-2 virus is contained in the sample, the protein components of the virus react with the test strip and a discoloration on the test strip becomes visible. Advantages of antigen tests are the comparatively low costs and the prompt test results