united kingdom children are always going to find cunning ways to bunk off school and the latest trick is to fake a positive covid19 lateral flow test lft using soft drinks so how are fruit juices cola and devious kids fooling the tests and is there a way to tell a fake positive result from a real one ive tried to find out first i thought it best to check the claims so i cracked open bottles of cola and orange juice then deposited a few drops directly onto lfts sure enough a few minutes later two lines appeared on each test supposedly indicating the presence of the virus that causes covid19 its worth understanding how the tests work if you open up an lft device youll find a strip of paperlike material called nitrocellulose and a small red pad hidden under the plastic casing below the tline absorbed to the red pad are antibodies that bind to the covid19 virus they are also attached to gold nanoparticles tiny particles of gold actually appear red which allow us to see where the antibodies are on the device when you do a test you mix your sample with a liquid buffer solution ensuring the sample stays at an optimum ph before dripping it on the strip the fluid wicks up the nitrocellulose strip and picks up the gold and antibodies the latter also bind to the virus if present further up the strip next to the t for test are more antibodies that bind the virus but these antibodies are not free to move they are stuck to the nitrocellulose as the red smear of goldlabelled antibodies pass this second set of antibodies these also grab hold of the virus the virus is then bound to both sets of antibodies leaving everything including the gold immobilized on a line next to the t on the device indicating a positive test gold antibodies that havent bound to the virus carry on up the strip where they meet a third set of antibodies not designed to pick up covid19 stuck at the c for control line these trap the remaining gold particles without having to do so via the virus this final line is used to indicate the test has worked acid testso how can a soft drink cause the appearance of a red t line one possibility is that the drinks contain something that the antibodies recognise and bind to just as they do to the virus but this is rather unlikely the reason antibodies are used in tests like these is that they are incredibly fussy about what they bind to theres all sorts of stuff in the snot and saliva collected by the swabs you take from the nose and mouth and the antibodies totally ignore this mess of protein other viruses and remains of your breakfast so they arent going to react to the ingredients of a soft drink a much more likely explanation is that something