Recommendation 16

A number of significant commentators, including the British Medical Association and British Medical Journal, have raised concerns about the effectiveness and risks of mass testing with LFD tests.55 A particular issue raised is the relative accuracy of LFD tests compared to PCR tests and the higher risk of false negatives.56 Published evidence indicates that LFD tests had a sensitivity of only 77% (broadly, if 100 people with the infection take the test, only 77 of them will return a positive result). NHST&T considers LFD tests a “very useful addition to our overall testing toolkit”.57 But the interim evaluation of the Liverpool mass testing pilot found that, when self-administered, LFD tests overall only detected 40% of positive cases detected by PCR tests. In the evaluation, LFD tests did detect a higher proportion of positive PCR tests—around two thirds—when individuals had a higher “viral load” and were more “substantially infectious”.58 While the authors of the Liverpool evaluation pointed out the benefits of LFD tests in identifying many infectious asymptomatic cases who would otherwise go undetected, they also stressed the need to communicate clearly that when people test negative, it does not provide assurance that they are not infectious.59