Ask Dr. Z

Code G0365 confuses me. Code 93971 is a complete upper or lower extremity study. For code G0365 to be used on the same day it has to be a different site. That would have to be a different extremity, correct? It says code G0365 may only be utilized in patients who have not had a prior hemodialysis access prosthetic graft or autogenous fistula and is limited to two times a year. Then it says, if code G0365 is performed on the same date of service as 93990, append modifer -59 to code G0365. Does the second statement mean that if the graft/fistula becomes unusable then the first statement does not apply and code G0365 can be used on a site away from the graft?