Question: We have two oncologists in our multi-specialty group of 65 doctors. When one of us takes a vacation, the other physician covers. Should we document any special modifiers, such as -Q5 and -Q6? Typically, we submit charges based on the patient's physician rather than who was present in the office during the visit. Texas Subscriber Answer: Physicians who practice in a group usually bill their services under the group name and ID. You should list the rendering physician based on who was present and who provided the service. Therefore, you shouldn't append modifier -Q5 (Service furnished by a substitute physician under a reciprocal billing arrangement) when you submit claims under a group number. In addition, you should not attach modifier -Q6 (Service furnished by a locum tenens physician) because the modifier represents locum tenens billing. That is, the primary physician reimburses the substitute physician on a per-diem rate, because the substitute physician has the status of an independent contractor rather than an employee.