An integrated medical database system for the emergency medical transportation business. The system includes a dispatch and demographic module, a clinical module, an administration module and a billing module. Each module may communicate data with one or more of the other modules to form a system incorporating data sharing, thus achieving an end-to-end automation of emergency medical care accounting. Internal consistency checks are performed by the system to ensure that proper treatments are performed according to a chosen diagnosis. The system includes a billing modifier module operating on data from the dispatch and demographic module. In one embodiment, the billing modifier module applies Geographic Practice Cost Index (GPCI) and Metropolitan Statistical Area (MSA) billing modifiers based on modifiable computerized rules so as to provide a more accurate charge to the payer. The results of the billing modifier module are forwarded to the billing module.