Modifier 51 & clinic procedures

Our provider coded a 57455 (Colposcopy of cervix w/biop) and 58110 (Endometrial sampling/biop in conjuction w/Colposcopy. Dx 795.04 was given. It was done in the clinic. I billed it with a modifier 51 as 25 can't be used on procedures. As there was only one dx given I felt a modifier was needed. However, the Insurance denied it due to the Modifier 51 saying it was invalid. How would I bill this correctly?

re: Modifier 51 & clinic procedures

I would look at the NCCI EDITS and see if you need to add modif 59 seperate procedure.