Officials are urging anyone who develops COVID-19 symptoms to self-isolate, even if their COVID-19 tests produce negative results. The calls follow a string of reports highlighting disparities in accuracy between lateral flow and PCR tests. The UK Health Security Agency said it was investigating the matter, after a “stream of patients” who had initially received positive lateral flow tests, went on to receive negative PCR results.
The recent findings have once again thrown the accuracy of COVID-19 tests into question, prompting calls for the issue to be looked into “seriously” and “rapidly”.
Becky Reynolds, director of public health for Bath and North East Somerset Council, said the council was aware of the situation.
She explained: “It is confusing [for people]. I think we just need to bear with it while the investigation happens.
“The advice is also to think about your local situation, do an individual risk assessment… so what is the likelihood that even though the PCR is negative, that you may still have Covid.
“If thinking it through there is quite a chance you have Covid, even if the PCR is coming back negative, then regard it as Covid and self-isolate.”
Doctor Lucy Pocock, a GP from Cadbury Health Healthcare in south Gloucestershire, told BBC: “Myself and my colleague have seen a stream of patients with what we would consider very typical Covid symptoms.
“Several of these patients have done multiple lateral flow tests, all positive, and have then rightly gone on to do a PCR test, which has come back negative.
“The worrying thing here is that these people are all clearly symptomatic and with a very unexpected negative PCR result.”
Chief medical advisor for the UK Health Security Agency, Susan Hopkins, said: “We have been made aware of some areas reporting positive Lateral Flow Test results with subsequent negative PCR test and we are looking into the cause.”
Kit Yates, an adviser for the Scientific Advisory Group for Emergencies [SAGE], has called for a prompt investigation, arguing that it may not be practical for some to self-isolate.
He added that the mystery could have “huge implications” for our understanding of the pandemic.
The SAGE member told the I he had previously heard of a dozen separate instances of the issue.
“We haven’t experienced this before to such a degree and are investigating.”
While lateral flow tests occasionally produce a false negative result, false positives are much rarer.
A number of hypothetical explanations for the inaccurate test are circulating on social media, with some users suggesting a faulty batch could be behind the false-negative results.
Others have theorised that the tests might not be picking up a new variant of COVID-19.