Negative SARS-CoV-2 test data

[elsie-h]

I was planning to create a variable counting the number of SARS-CoV-2 tests (any result) during a period, but I noticed that on the COVID-19 test results documentation page it reads:

"Negative test data is unreliable — DO NOT USE"

Is this information up to date, and should I avoid deriving such variables?