Question: My practice employs both physicians as well as nonphysician practitioners (NPPs). We've had some issues where our claims from patient encounters with NPPs are getting denied from certain payers. What are we doing wrong? California Subscriber Answer: If that particular payer is UnitedHealthcare, you may have noticed that you've been having issues with successful claims for the past six months. All claims for evaluation and management (E/M) services dated on or after Sept. 1, 2017, require modifier SA (Nurse practitioner rendering service in collaboration with a physician) when these services are provided by nurse practitioners (NPs), physician assistants (PAs), and clinical nurse specialists (CNSs), said the UnitedHealthcare's June 2017 Network Bulletin. But don't forget one of the golden rules of billing: Each payer has different requirements. Make sure you check with each individual insurer as to what they require and when, especially as the use of a particular modifier may impact reimbursement. "The CPT® and CMS modifiers are generally well-known to the billing professionals of small and/or large practices," says Catherine du Toit, CPC, CPMA, CGIC of Clean Claims Coding Consultants. "If each insurance carrier is planning to add its own set of modifiers to indicate that NPs, PAs, and other clinical staff members performed E/M services in collaboration with the physician, things could get confusing."