Amid the many tests in development for Covid-19, Luminostics believes that it has a new approach in the shape of a smartphone-based self-test – and has hooked Sanofi as a partner. This involves a respiratory sample being taken by the patient at home and processed using nanoparticles that bind to the coronavirus’s genetic material. The test is run in an adaptor that clips onto a phone; if viral RNA is present a chemical reaction results in a luminous signal detected by the phone’s camera in 30 minutes, the companies say. To say that this tech is unproven is an understatement: it does not appear to include an RNA amplification step like PCR; the sensitivity of phone cameras varies; and patients’ sampling skills will vary even more. Luminostics claims that its tests can detect molecules at low femtomolar levels, but Leerink says some sort of amplification will be necessary – perhaps an isothermal process similar to that used in Abbott’s ID Now platform. But Abbott’s test has itself run into accuracy questions. It might eventually be possible to have a self-testing system for Covid-19 antibodies, similar to a pregnancy test, but one for viral RNA is a much harder ask.