Implementing outpatient order entry to support medical necessity using the patient's electronic past medical history.

Physician order entry is difficult to implement, both in inpatient and outpatient settings. Such systems must integrate conveniently into clinical workflows, and provide sufficient benefit to offset the burden of system use. For outpatient order entry, significant advantages can accrue when systems incorporate medical necessity guidelines - improved billing and adherence to governmental policies. The authors developed and implemented an outpatient order entry system that utilizes an electronically accessible history of patient, provider, and clinic-related diagnoses in assisting providers (when possible and appropriate) to select compliant justifications for tests and procedures. The pilot implementation site, active for more than six months, has been the Vanderbilt University Page Campbell Cardiology Clinic, with 34 providers.