Modifier AG: Primary Physician in a Scarcity Area
Modifier AG identifies a primary physician and is a Medicare informational modifier tied to physician scarcity area reporting. Usage and placement.
When to Append Modifier AG
Append AG to identify the service as that of a primary physician, in the Medicare context associated with primary care delivered in a designated physician scarcity area.
Source: HCPCS Level II official descriptor
Modifier AG in Detail
Modifier AG identifies the service as that of a primary physician. It is a Medicare-only informational modifier associated with primary care delivered in a designated physician scarcity area, where Medicare has historically applied incentive payments to improve access in underserved geographies.
Because it is informational rather than pricing-related, AG does not change how the procedure itself is priced. It is reported after any other applicable modifiers, and it sits alongside standard Medicare billing requirements for primary care practices. Shortage area designations are a Medicare billing rule, and the full set is listed in the billing modifiers library. Modifier use is a compliance matter as much as a billing one, covered in medical billing compliance.
Using Modifier AG Correctly
When to Apply
Apply this modifier only when the clinical circumstances described in the modifier definition are present and documented in the medical record.
Procedure Code Compatibility
Confirm this modifier is applicable to the procedure codes being billed. Not all modifiers are valid with all CPT codes.
Documentation Support
Ensure the medical record supports the modifier's use. Auditors will review documentation to confirm the modifier is appropriate.
Payer Acceptance
Verify that the payer accepts this modifier and understand how it affects reimbursement before submitting the claim.
Modifier AG Reference
| Field | Details |
|---|---|
| Modifier | AG |
| Official Description | Primary physician. |
| When to Use | Append AG to identify the service as that of a primary physician, in the Medicare context associated with primary care delivered in a designated physician scarcity area. |
| Modifier Type | Informational. It does not alter the pricing of the procedure code it accompanies. |
| Placement on the Claim | Because it is informational, AG is reported in the last modifier position, after any modifiers that affect pricing or describe the service itself. |
| Who It Applies To | Primary care physicians, typically general practice, family practice and general internal medicine, rather than specialists. |
| Before Using It | Confirm the designation currently applies to the practice location and that the payer still recognises the modifier, since scarcity area designations and associated incentive programmes are revised over time. |
Source: HCPCS Level II official descriptor
Related Billing Resources
Modifier AG, Frequently Asked Questions
Append AG to identify the service as that of a primary physician, in the Medicare context associated with primary care delivered in a designated physician scarcity area.
Having Trouble With This Code?
Our billing specialists can help you resolve denials, improve coding accuracy, and reduce claim rejections.
Sign up for our newsletter to receive updates, industry news, and articles about medical billing and revenue cycle management.