Ask Dr. Z

I would appreciate some clarification regarding the use of modifier -50 in vessel catheterizations. My understanding of modifier -0 is that it is for “pairs” of left and right. Can I use modifier -50 with the CPT 3624X series when left and right are different vessels but are of the same order? Example: on the left, 3rd order catheterization of the obturator artery. On the right, 3rd order catheterization of the internal pudendal artery. We have left and right 3rd order catheterizations, but they are not the same vessels. Eligible for modifier -50?