Question: Our nurse practitioner (NP) is often called upon to provide services to our patient. What is the best way to document this and make sure we receive the full reimbursement? Vermont Subscriber Answer: First, assuming that you are dealing with Medicare or a payer that follows Medicare guidelines, make sure you are following the Centers for Medicare and Medicaid Services (CMS) regulations for incident-to services. This means that: (Take a further look at the CMS incident-to policy at: https://www.cms.gov/Outreach-and-Education/Medicare-Learning-Network-MLN/MLNMattersArticles/downloads/se0441.pdf) Next, you need to make sure that these services are billed under the supervising physician's National Provider Identifier (NPI) number. This is critical, as Medicare and payers who follow Medicare guidelines will pay 100 percent when you bill this way; when you bill a service under the nonphysician provider's (NPP's) NPI, however, payment is only 85 percent of the amount otherwise paid to a physician. Finally, attach HCPCS Level II modifier SA (Nurse practitioner rendering service in collaboration with a physician) to the service when required, as Medicaid and payers using Medicaid guidelines require the modifier to be used whenever an NPP performs a service under the physician's NPI. So, if your NP provides a level three evaluation and management (E/M) service to an established patient, you would document 99213 (Office or other outpatient visitfor the evaluation and management of an established patient ...) along with the SA modifier.