Unlike conventional PCR tests, rapid antigen tests do not search laboriously for the genetic material of the virus in swab samples, but for molecules that are characteristic of the virus. The quick tests are comparatively easy to carry out: As a “lateral flow test” it works on a similar principle to the pregnancy test. But there are some differences. In the rapid antigen test, a sample is taken from the nasopharynx and tested for the presence of the antigen specific for Sars-CoV-2 – the nucleocapsid protein, a protein from the virus core. During the pregnancy test, the urine is examined for the pregnancy hormone HCG. Both tests are similar in the way they display their results. Two colored strips (test and control strips) indicate a positive result, one strip indicates a negative result (the control strip) and no strip indicates that the test is invalid. The results are usually available within 15 minutes.