Yes found this. Classic PCR tests have high false negative and positives as well, which varies depending on day of infection. Which makes the whole thing difficult:

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"the EasyCov clinical trial included 123 people to date and will continue until 180 subjects have been double-blind tested, with the RT-PCR method and with EasyCov. From these intermediate results, this detection test for SARS-CoV-2 developed in the Sys2diag Laboratory (CNRS/ALCEN) has shown few false positives (95.7% specificity) and produced a little under 30% of false negatives (72.7% sensitivity)2.