Same-day procedures don't mean the denial is appropriate -- verify before writing off the charges. As a biller, you may not actually assign the codes and modifiers to claims for your physician's services. But if the coding is the reason your claim gets denied, you'll need to do some investigative work. Modifiers are an area of coding that causes many claims errors, so even if you don't code physician services you should know which modifiers apply in which clinical situations. Things get even more complicated when the physician is reporting two procedures on the same date of service and you need to determine the most appropriate modifier to explain the clinical circumstances to the payer. Use this flowchart to quickly assess some of the most common modifier assignments before you start your appeals.