There's lots and lots of samples being tested for flu. Is the theory then that there is some bias where the hidden cases don't get tested for flu at all and onl

There's lots and lots of samples being tested for flu. Is the theory then that there is some bias where the hidden cases don't get tested for flu at all and only mistakes are sent for testing? https://www.cdc.gov/flu/weekly/index.htm https://www.cdc.gov/flu/weekly/index.htm It says right on the page that Covid makes the data difficult to interpret, the thing I'm pointing to is the 900,000 samples tested.