we had a pt come in with low pelvic pain, this pt also has history of gallbladder cancer. He saw our NP who in turn consulted the PA, due to the MD being out of the office. The PA suggested doing a post void US. The pt was then sent to the Surgical Oncology clinic where the RN performed the post void US. Would I code out the E/M along with the 51798 but attach a modifer 25 to the E/M? Also are we able to bill the 51798 due the RN performing this US?