If your billing for the physician, you will use a 1500, ASC needs to be on the UB-04, you can actually go on line and type in how to fill out a UB-04 and it should tell what specifics you need on each line. You could also maybe get help from your clearinghouse ? I hope this helps, you have to make sure your referring doctor is there and the billing address of the facility, I think in box 32a. Not sure what your questions are ?