My Best Friend Has Had An Echogram Recently, Showing An

My best friend has had an echogram recently, showing an EF of less than 30% ... however, he felt the technician 'lift' the transducer from close-contact with his skin, and he is able to run up a flight of stairs, go for a three mile walk and exercise without difficulty, dizziness or breathlessness. Is it at least possible that the ejection fraction is in error? And should he have the Echocardiogram re-done?