Hint: Only append modifier AS in certain circumstances. Along with ICD-10-CM and CPT® codes, modifiers are an integral part of your medical claims. If you append the incorrect modifier or forget to append a modifier, your claim will be denied. So, you must know in which situations you should append modifiers and which modifiers you should use. For example, if your cardiologist acts as an assistant surgeon during a procedure, you should be familiar with the three types of assistant surgeon modifiers. Know Why Cardiologist May Act as Assistant Surgeon A primary surgeon may use an assistant surgeon for several reasons, such as a particularly complex procedure or patient condition. In this case, the assistant surgeon works under the direct supervision of the principal surgeon. Medicare requires the primary surgeon to list the assistant surgeon in the operative report and to make some notation within the procedure description regarding how the assistant was involved. Sometimes the surgeon you code for might act as the primary surgeon on the case, and sometimes he might act as the assistant surgeon, which will impact your coding. The primary surgeon should bill the procedure without a modifier, while the assistant surgeon must append the appropriate modifier to the same procedure code. Definition: According to Medicare guidelines, “an assistant at surgery must actively assist when a physician performs a Medicare-covered surgical procedure. This necessarily entails that the assistant be involved in the actual performance of the procedure, not simply in other, ancillary services.” Medicare guidelines continue: “Since an assistant would, thus, be occupied during the surgical procedure, the assistant would not be available to perform (and thus, could not bill for) another surgical procedure during the same time period.” Discover Assistant Surgeon Modifiers CPT® provides the following three assistant-surgeon modifiers: As you can see, the distinction between modifiers 80 and 81 lies in whether the assistant surgeon participates during the entire procedure or just a portion of it. Modifier 82: You should reserve modifier 82 for cases in a teaching hospital when a qualified resident is not available, so an assistant surgeon participates in the entire procedure. Medicare defines “qualified resident not available” to mean the following circumstances: Remember to Append Modifier AS for Specific Cases Medicare will only pay for a surgical assistant when the procedure performed is authorized for an assistant, and the person performing the service is a physician, physician assistant (PA), nurse practitioner (NP), or a clinical nurse specialist (CNS). When a PA, NP, or a CNS assists at surgery, you should append modifier AS (Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery) to the surgical code along with modifier 80. Without modifier AS, modifiers 80, 81, and 82 indicate that a physician was the surgical assistant. So, claims you submit that include modifier AS without modifier 80, 81, or 82 will be returned to you. Caution: Many commercial insurers follow Medicare’s rules, but not all do. Be sure to query each of your payers to find out their policies on billing for surgical assistants. They may want only the modifier AS, or they may not recognize it at all. Research Assistant Surgery Indicators Before you bill for an assistant at surgery under the Medicare Physician Fee Schedule (MPFS), you should always double-check the ASST SURG column to verify that the procedure(s) allows an assistant. Payers will not reimburse you for assistants at surgery in all cases, regardless of the modifier(s) you attach to the claim. For Medicare, assistant at surgery services are eligible for reimbursement only when national claims data indicates the procedure would require an assistant in at least 5 percent of the claims based on a national average, according to Medicare guidelines. Look for these designations in the ASST SURG column: Example: Code 93656 (Comprehensive electrophysiologic evaluation including transseptal catheterizations, insertion and repositioning of multiple electrode catheters with induction or attempted induction of an arrhythmia including left or right atrial pacing/recording when necessary, right ventricular pacing/recording when necessary, and His bundle recording when necessary with intracardiac catheter ablation of atrial fibrillation by pulmonary vein isolation) has a “0” ASST Surg designation, so Medicare will only allow payment for an assistant at surgery if you submit supporting documentation that establishes medical necessity.