Would some pathologist explain to me how they know it's the coronavirus?

[Dennis Donovan]

2. Not sure of the actual tests, but this was in the NYT piece yesterday about a potential pandemic:

Wuhan Coronavirus Looks Increasingly Like a Pandemic, Experts Say

<snip>

It’s unclear exactly how accurate tests done in overwhelmed Chinese laboratories are. On the one hand, Chinese state media have reported test kit shortages and processing bottlenecks, which could produce an undercount.

But Dr. Lipkin said he knew of one lab running 5,000 samples a day, which might produce some false-positive results, inflating the count. “You can’t possibly do quality control at that rate,” he said.

</snip>