Using a modifier incorrectly can cost you in terms of reimbursements and time. Carriers are closely scrutinizing medical billing claims for incorrect usage of modified 59. There are two main areas that you can concentrate on to avoid getting his with denials or pay backs and insure that you use the modifier correctly. A study of the OIG found a 40% error rate for modifier 59 and you can double check your billing. First of all, in order to use modifier 59 there must be services performed at separate regions. Fifteen percent of the OIG’s audited claims using modifier 59 had procedures that weren’t distinct because “they were performed at …