https://www.cdc.gov/coronavirus/2019-ncov/php/reporting-pui.html
CDC meaning of “presumptive positive”:
“Presumptive Cases (persons with a positive test performed locally without CDC lab confirmation)”
“presumptive positive cases (individuals with at least one respiratory specimen that tested positive for the virus that causes COVID-19 at a state or local laboratory”
A case is only positive for COVID-19 when the CDC does the testing and confirms it.
Those numbers generated by tracking only the positive CDC cases are missing many cases and will miss more when more states begin testing.
NY
Vanderbilt U. student tests positive after coming home to Plainview NY from Spain: