We hear a lot about corona-testing these days! Currrently, the most used (and fastest) test is based on an assay, that is named PCR (Polymerase Chain Reaction).
With this technology, it is possible to detect the presence of COVID-19 in a patient sample by purification and amplification of specific gene sequences from the viral RNA (genetic material). These gene sequences were published by Chinese researchers shortly after the beginning of the outbreak.
This animation describes the principle of a PCR (more specific, a RT-PCR) reaction.
My friend Frédéric Eghiaian was so kind to make the music for this animation.