Should I test for Radon if there is only a crawlspace in my home or I am in a 2nd floor unit?

Radon levels above the EPA’s Action Limit (the concentration limit that should never be exceeding in a home) have been found on second floor dwelling units.  The Surgeon General and EPA both recommend testing for radon an any level below the 3rd floor.  The 3rd floor is defined as the third floor level from the ground.

Read more here: https://www.epa.gov/sites/production/files/2015-05/documents/hmbuygud.pdf