These rules govern reporting of beyond-guideline time Not sure how to get paid when you exceed the time allocated to an E/M service? Turn to modifier 21 or prolonged service codes. "Payment may be problematic," says Richard H. Tuck, MD, FAAP, a pediatrician at PrimeCare of Southeastern Ohio. But here's when each is appropriate. Rule 1: When the time spent on an E/M service goes less than 30 minutes past the typical time for the highest E/M code in a family (for office or other outpatient services 99205 and 99215; for hospital inpatient services 99223 and 99233), you may use modifier 21 (Prolonged evaluation and management services) on the E/M code. Rule 2: Use prolonged services in addition to the E/M service code when care is 30 minutes or more beyond the usual service of a time-based code, says Jeffrey F. Linzer Sr., MD, FAAP, FACEP, associate medical director for compliance and business affairs at EPG in Egleston, Ga. The time does not need to be continuous. "I can spend 10 minutes with the patient, go away and come back later," he says. Rule 3: Count the cumulative time you spend providing that patient either direct (face-to-face) or without direct services (+99358, Prolonged evaluation and management service before and/or after direct [face-to-face] patient care [e.g., review of extensive records and tests, communication with other professionals and/or the patient/family]; and +99359, ... each additional 30 minutes) on that given date. Before or after face-to-face services include: Rule 4: Choose the direct prolonged service code based on the site of service. For outpatients use: Inpatient codes include: