"Since no quantified virus isolates of the 2019-nCoV were available for CDC use at the time the test was developed and this study conducted, assays designed for detection of the 2019-nCoV RNA were tested with characterized stocks of"

Source of quotation

CDC Pamphlet downloadable at FDA

Archived on the way back machine or webdotarchive dot org at the following link at that specific time period

http://web.archive.org/web/20210901224937/fda.gov/media/134922/download

No Covid 19 virus has been found see this CDC pamphlet on FDA website