All mastering engineers have perfect 20-20k hearing.
Anybody here get tested regularly? I've been bad. it's been a few years for me. I should schedule a cleaning and a test. Also, to get a reading above speech frequencies, you need to request an extended range test. Not everybody offers these, and they require some extra time which is why you need to let them know when making the appointment.
Then again, I guess if you don't know, you can continue along in blissful ignorance. You'd be surprised at some of the guys able to do good work that are lucky to be able to hear 15k. I know of one guy who can only hear up to 12k and keeps an RTA on all the time. I always think his stuff is too bright though.