Contradictheory: What's with the different tests for Covid-19?

While experts still debate the efficacy of the different types of test kits available to detect Covid-19, Malaysia’s Health Ministry recently reversed itself and added the antibody test kit to its testing regime, to be used ‘under certain conditions’. — AFP

A few weeks ago, Malaysia's Health Ministry put out an infographic that showed the differences between the different ways of testing people for the Covid-19 virus. One is the RT-PCR test (or just PCR) that the government is currently using to test patients; the second is a Rapid Test Kit Antigen (RTK Antigen) test that is being considered; and the third is a Rapid Test Kit Antibody (RTK Antibody) test.

The infographic was wordy but the most prominent phrase was “the Rapid Test Kit Antibody CANNOT be used to detect Covid-19” (translated from Malay).