Beware of modifier 51 for add-on procedures. Add-on codes can augment your payment for additional procedures that your surgeon does; if you're omitting or adding these improperly, chances are you're losing deserved pay with every claim. Read on for a refresher on reporting the base code and accurately documenting the indication and the procedure for add-ons to unblock jammed payment. . Don't Overlook Primary Procedure Remember that an add-on code cannot be a standalone code. You will need an accompanying primary procedure code. An add-on code hence is indicative of an additional intraservice work that your clinician does in a single session or patient encounter. An example is the add-on code +29826 (Arthroscopy, shoulder, surgical; decompression of subacromial space with partial acromioplasty, with coracoacromial ligament [i.e. arch] release, when performed [List separately in addition to code for primary procedure]) for shoulder arthroscopy. Some common arthroscopic primary procedures include the arthroscopic distal clavicle excision, arthroscopic rotator cuff repair, and arthroscopic debridements. "The add-on code +29826 is allowed with CPT® codes 29806 (Arthroscopy, shoulder, surgical; capsulorrhaphy) " 29825 (Arthroscopy, shoulder, surgical; with lysis and resection of adhesions, with or without manipulation), 29827 (Arthroscopy, shoulder, surgical; with rotator cuff repair) and 29828 (Arthroscopy, shoulder, surgical; biceps tenodesis)," says Kristi Stumpf, MCS-P, CPC, COSC, ACS-OR, owner, Precision Auditing and Coding, senior orthopedic coder & auditor, The Coding Network, Washington. Exception: Avoid Modifier 51 You should never append modifier 51 (Multiple procedures) to an add-on code that you are reporting. "Do not add the 51 (Multiple procedures) modifier to an add-on code," says Stumpf. Example 1: CPT® clearly specifies "All add-on codes found in the CPT book are exempt from the multiple-procedure concept." Example 2: Example 3: (Allograft, morselized, or placement of osteopromotive material, for spine surgery only (List separately in addition to code for primary procedure) - +20938 (Autograft for spine surgery only [includes harvesting the graft]; structural, bicortical or tricortical [through separate skin or fascial incision] [List separately in addition to code for primary procedure]). Spinal bone grafts are add-on procedures associated with a definitive spine surgery. "Bone graft codes are modifier -51 exempt because they are add-on codes and need to be reported with the arthrodesis codes," says Jennifer Schmutz, CPC, health information coder at the Neurosurgical Associates, LLC in Salt Lake City, Utah. Earn Your Deserved Payment Make sure your payment is in accordance to the fee schedule rate. Note that the fee schedule amounts assigned to add-on codes already reflect their status as "additional procedures." The logic of reduction of payment for the second and other following procedures when the surgeon does multiple procedures does not apply to the add-on procedures. You can go ahead and appeal your claims if your payment has been reduced or denied for an add-on code. You can cite in support the CPT® definition of add-on codes as 'additional procedures exempt from modifier 51 rules.' "The CPT® definition of add-on codes can be found in the Introduction section of the CPT® Manual and a complete list of add-on codes is found in Appendix D," adds Stout.