
Modifiers
Ai – Principal Physician of Record Modifier
Principal physician of record. Commonly appended to admitting physician claims. Helps avoid denials via duplicate billing error.
Signals to payers (like Medicare) which doctor is in charge, allowing patient’s same-day consulting specialists to bill their own E/M codes without the claim being rejected as duplicate billing.
For use with codes exclusively to initial hospital care (99221–99223) or initial nursing facility care (99304–99306)
Billing Provider Role
Clearly define who is the admitting or attending physician responsible for managing the patient’s comprehensive care.
Standard Record Documentation
- Initial admitting orders
- comprehensive plan of care written, signed, or verified by that principal physician.
Scenario: A patient is admitted to the hospital with acute heart failure and severe chronic obstructive pulmonary disease (COPD) exacerbation. Two physicians examine the patient on the initial day of admission and document comprehensive medical decision-making (MDM).
- Cardiologist: Admitting physician who manages the overall inpatient stay.
- Pulmonologist: Consulting specialist called in to manage the acute COPD.
Cardiologist’s initial note explicitly states: “Patient admitted under my service for acute heart failure management. Initial plan of care established…”
Coding Solution:
- Cardiologist submits: CPT code 99223 with modifier -AI appended (99223-AI).
- Pulmonologist submits: CPT code 99223 without the modifier
The payer processes and pays both high-level initial claims on the same day because the -AI modifier successfully identifies cardiologist as the principal physician, preventing Pulmonologist consulting claim from being rejected as a duplicate billing error.