https://www.fda.gov/media/134922/download
Page 39: Performance Characteristics
“Since no quantified virus isolates of the 2019-nCoV are currently available...”
The key word in that sentence is “quantified.”
They are trying to determine how many coronaviruses must be present in a micro-liter sample for the PCR test to show positive.
They would prefer to use quantified “live” virus samples - in other words, samples with a known number of live viruses in each sample.
However, they do not have such samples, which most likely would be very expensive to make and would require extreme safety procedures.
Instead, they reproduce just the RNA in the lab, and count how many copies of the RNA are in each micro-liter so they can certify the PCR test.
If they know how to reproduce the RNA in the lab, they have to have a sample of a live virus some place, even if it is not the coronavirus.
...even if it is not the coronavirus.
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If it’s not coronavirus, how can it be a coronavirus isolate?
Also: don’t they utilize amplification to get enough viral fragments to test?
I’d be happier if test results were accompanied by the information of how many cycles of amplification were used when they report a positive test.
I’d say the language is opaque.