Which statement describes the master patient index?

• A. It is used to uniquely identify patients across multiple information systems
• B. It is a database of all tests
• C. It is used to schedule appointments
• D. It stores imaging data

Answer: (A)

The master patient index ensures unique identification of an individual across the organization’s different information systems, so all of that person’s records—whether in the electronic health record, labs, radiology, or other systems—can be linked to one patient. This supports a single, longitudinal view of the patient’s data and helps prevent duplicates or misattribution as information moves between systems. It relies on demographic data and matching logic to tie together records that belong to the same person, even when they appear in multiple databases.

This isn’t a database of all tests, nor is it used to schedule appointments, and it doesn’t store imaging data (which are kept in imaging-specific systems).