An explaination why positive test results from RT-PCR tests are more than likely to be wrong – and why, if you’ve had a positive test result, you should make sure you’re re-tested. If compulsory self-isolation following a positive test result has a major negative impact on your work or other aspect of your life, you should think about demanding multiple re-tests.
Concerns about false positives become ever more real if you're trying to push towards millions of tests daily, as the UK government is with its Operation Moonshot. Leaked documents reveal that “new types of test [non-PCR] are likely to be less accurate [than PCR], introducing some [additional] level of risk.”, raising even greater concern.

Source:
https://www.anhinternational.org/news/why-your-positive-test-result-is-likely-wrong/?fbclid=IwAR2Givd61ZhmzqbqCGah0w38vyXAazaaHgAtbmvfnrTQZs-XPl5leS2alP4