I have not researched this heavily, but the tests do not seem to be very good. It seems like RT-PCR is more sensitive than the IgM/IgG antibody test for mild,

I have not researched this heavily, but the tests do not seem to be very good. It seems like RT-PCR is more sensitive than the IgM/IgG antibody test for mild, moderate and normal group.¹ And a negative result of a RT-PCR test a few days past the peak would reduce our estimate of the relative probability that a case patient was infected by only 3%.² [1] https://www.researchgate.net/publication/343570266_Comparison_of_real-time_reverse_transcriptase-polymerase_chain_reaction_RT-_PCR_and_IgM_and_IgG_antibody_test_for_the_diagnosis_of_SARS-CoV-2_infection https://www.researchgate.net/publication/343570266_Compariso... [2] https://www.acpjournals.org/doi/10.7326/M20-1495 https://www.acpjournals.org/doi/10.7326/M20-1495