A widely shared post on Facebook claims that lateral flow tests are “a big farce” because pouring some diluted cordial onto one appeared to give a positive Covid-19 result. The poster also claims this means they would falsely test positive after drinking.
As we have written many times before, the acidity in some foods and drinks can break a test and cause a second line to appear, as if the test were positive.
This does not mean that the tests are unreliable when used correctly, and it does not mean that the foods and drinks used to break the test are really positive for Covid-19.
Lateral flow tests are unlikely to give a false positive result if used correctly.
To avoid the risk of consumed food or drink affecting the result of a lateral flow test, government guidance states: “Do not eat or drink for at least 30 minutes before doing the test to reduce the risk of spoiling the test.”
We have previously fact checked similar claims about ketchup, oranges, kiwi fruit and Coca-Cola.
Using food and drinks on lateral flow tests has been in the news after reports that pupils are attempting to get time off school by using liquids like lemon juice to create false positive results.