Does ejection fraction (EF) vary depending upon altitude?

Are ejection fraction test results the same at 5000 feet, as compared to sea level??? I believe that my EF testing is in error, since it is always done in a cold lab at 5000 feet. I run, yes run, 4 miles every day, without effort, without SOB, and, yet, the EF is never more than 35%. Since I also run up hotel floors (12 or more) at sea level, I just wondered if I would have a different EF at sea level?

Submitted by Terry from Socorro, New Mexico on 08/23/2015