Medical Billing And Second Observation Day Coding Eventually, when you’ve done enough medical billing, you will run across the scenario when a patient is in the hospital on a three day stay, a common belief among medical billers is that the a “middle” day of observation should be billed on the medical billing form as an Outpatient Visit (99212-99215). Many Carriers and Medicare will not reimburse a middle day visit coded in this fashion. Even with documentation for the middle day visit included on the medical billing form. The AMA’s position on the medical coding for this situation is that you report the middle/second day of a three day stay …