The basic unit of payment in the inpatient PPS is a hospital admission while the basic unit of payment in the OPPS is an outpatient visit. However, unlike the inpatient system that assigns a patient to a single DRG, multiple APCs can be assigned to one outpatient record. If a patient has multiple outpatient services during a single visit, the total payment for the visit is computed as the sum of the individual payments for each service.
Variation is attributable to rounding error of the computing platform.
Accuracy also varies with the currency of the hospital specific factors being used in the computation, as Medicare can make updates at any time. Us Copyright 2001, Micro-Dyn Medical Systems, Inc.