At least 4 different labs have claimed to have isolated the virus. So either they're all lying or covid does exist.

Here's the last paragraph of page 39, it's not doing much for me:

Test performance can be affected because the epidemiology and clinical spectrum of infection caused by 2019-nCoV is not fully known. For example, clinicians and laboratories may not know the optimum types of specimens to collect, and, during the course of infection, when these specimens are most likely to contain levels of viral RNA that can be readily detected.