echo help!

I'm having trouble finding guidelines on the frequency for echocardiograms. I need to know if a patient is in the hospital and multiple echoes are done can the doctor bill as complete echoes(93303) or all of the following studies after the initial test follow ups(93304)?

The hospital bills as follow up studies(93304) but my doctors say the test are read by them as complete studies. Can they bill different from the hospital charge?

Thanks,

Christina Davis, CPC

echo help!