Droplets of orange juice can break lateral flow tests and show a positive result .. Viral videos on TikTok have encouraged children across the UK to try the trend.. Schools have warned parents to be 'vigilant' when their children are tested .. Pupils have been using fruit juice to get false positive Covid-19 test results as schools warn parents to be 'vigilant'. When droplets of orange juice or fizzy drinks like coca-cola are placed on a lateral flow test it can produce a positive result because the acidity of the drink destroys the antibody proteins in the test. And although...