Covid 19 Virus Never Isolated

An FDA document says this:

Since no quantified virus isolates of the 2019-nCoV are currently available, assays designed for detection of the 2019-nCoV RNA were tested with characterized stocks of in vitro transcribed full length RNA (N gene; GenBank accession: MN908947.2) of known titer (RNA copies/µL) spiked into a diluent consisting of a suspension of human A549 cells and viral transport medium (VTM) to mimic clinical specimen.

See page 39 of CDC 2019 Novel Coronavirus ( 2019 nCOV) Real Time RT-PCR Diagnostic Panel.

Source: https://www.fda.gov/media/134922/download