Question: We have a coder who puts modifier 51 (Multiple procedures) on almost all claims for procedures. However, our MAC told us that they’ll automatically apply it when required. Is this accurate or should we keep using it? Wisconsin Subscriber Answer: You should most likely stop using it, depending on which payers you’re billing. “Medicare does not recommend reporting Modifier 51 on your claim,” said Part B MAC WPS Medicare in its Modifier 51 Fact Sheet. “The processing system has hard-coded logic to append the modifier to the correct procedure code.” Here’s why: If you bill multiple surgical procedures on the same date of service, the payer’s system has to determine how to price all of those procedures, so it ranks them by the fee schedule amount. The service allowed at the highest amount is paid at 100 percent, but the second through fifth procedures performed on the same date are reduced down to 50 percent. If the services that you bill apply to multiple procedure pricing, the system will add that modifier, so it could cause the payer to cut your pay by another 50 percent if you also append the modifier to your claims. Worse yet, your question suggests that your coder is applying this modifier even when you’re only billing one surgical procedure. This is another way that Medicare contractors have found practices to be shorting their reimbursement. One Medicare Quarterly Provider Compliance Newsletter edition indicated that “When only one surgical procedure is performed and modifier 51 is claimed, the reimbursement is inappropriately reduced by 50 percent … It is inappropriate to use multiple procedure modifiers when there is no second procedure performed.” Therefore, you should consider halting use of modifier 51 in general unless your payer instructs you otherwise. If so, get the insurer’s guidance in writing to ensure that you use the modifier correctly and continue to collect appropriate reimbursement. However, in that scenario if a separately identifiable E/M service is documented, append modifier 25 (Significant, separately identifiable evaluation and management service by the same physician on the same say of the procedure or other service) on the E/M code but leave the procedure unmodified.