How does testing work?
Generally speaking, Dr. Chatfield says, the test used to detect severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)—the virus that causes COVID-19—in animals is the same as that used in humans.
The real-time reverse-transcriptase polymerase chain reaction (PCR) test is not dependent on the subject being tested. “Rather, it’s dependent on the virus you’re looking for,” Dr. Chatfield says. “So, [the test] looks for a little piece of viral RNA in this case, because COVID-19 is an RNA virus, and amplifies the quantity of virus present to the point that it can then be detected with another test.”
It is important to keep in mind, Dr. Chatfield says, that just because a person or animal tests PCR positive does not mean they have the disease. “PCR indicates the presence of the viral material but not necessarily the viability of the virus itself.”