Ask Dr. Z

Some radiology codes state that two studies should not be coded on the same day unless performed during "separate encounters", in which case modifier -59 should be applied.

The question is how is an encounter defined? What constitutes a different session? Separate reports? If times are the same or within a few minutes, is this a separate session? We always have two separate reports - two orders - but the images were done minutes apart (the patient certainly never left the scanner). Is there a specific amount of time that needs to pass for it to be a new encounter? We have this issue come up with our US abdomen studies.