What does the Master Patient Index (MPI) primarily identify?

The Master Patient Index (MPI) primarily identifies all patients admitted to a health care facility for treatment. The MPI serves as a critical database used by healthcare organizations to maintain accurate and comprehensive patient records. It ensures that each patient has a unique identifier, which helps avoid duplications and discrepancies in patient information. This is especially important in the context of admissions, as it allows healthcare providers to manage and track all aspects of a patient’s care from the moment of admission to discharge.

The other options focus on specific groups within the patient population. While it is possible for all patients treated, discharged, or seen in outpatient settings and emergency rooms to be part of the MPI, the index's primary function relates specifically to those admitted for treatments, ensuring that the continuity of care is tracked accurately throughout the hospital stay.